January 2009

Check out the New Animated Underfloor Heating Website at:

www.qpl.ie/ufh/video

table of contents

Quality Plastics Limited 05Foreword 05Background 06Guarantee and products 08

Overview 09

Floor Materials 10Screed 10Concrete 10Insulation 11Damp Proof Membrane 13

Floor Structures – Standard 14Screed above sub-floor 14Thin screed above sub-floor 16

Floor Structure – Pre-cast Slab 18Screed above pre-cast slab (pre-formed insulation) 18

Screed above pre-cast slab (multi-reflective insulation) 20

Floor Structure – Suspended Timber Floor 22Suspended timber (dry method) 22

Suspended timber (wet method) 24

Floor Finishes 26Carpet 26Tile 27Timber 27

-Hardwood Floor 28-Moisture Content 28

Installation procedure of Pipe work 29Installation 29

Damage to pipe 30Pipe in-transit 30Proximity to other services 30

Boiler Consideration 31Boiler pipe work and distribution system 31

Primary / secondary pipe work and distribution system 31

index 03

index04

System Components 34Manifolds 34• description 34• location 34

Mixing valve 35• 22mm 35• 28mm 35

Floor Mixing Unit 36

Pump 36

Typical System Layout 37

System Control 38Standard Components 38• Room thermostats 38• Programmable room thermostats 38• Wet area probe and sensor 38• Wiring Centre 38• Actuators 39• Time Clock 39• Heating Control Panel 39

Radio Frequency 40• RF room thermostats 40• RF Programmable room thermostats 40• RF Wiring centre and receiver 40

System operation and guidelines 41Suggested cable sizes 41Time control and temperature setback 41

System Commissioning 42Filling 42Flow meter adjustment 42Flow meter cleaning 43System set up 43System start up 43System water treatment 44Maintenance 44

Guidelines for Homeowners 44

Design Considerations 45

Trouble Shooting Guide 46

Frequently Asked Questions 47

Notes 49

foreword 05

foreword

Quality Plastics Limited (QPL) has been in the business of producing quality goods forthe Plumbing, Construction and Agricultural sectors for nearly forty years, specialising inthe extrusion of polyethylene pipe for these applications. The product range has evolvedover this time to the latest generation of Qual-PEX thermoplastic pipes which can carryHot and Cold Water.

Qual-PEX crosslinked polyethylene barrier pipe from QPL is truly a first in thisgeneration of thermoplastic pipes – being the first PEX pipe ever to have been approvedto the BS 7291 kitemark and also holding WRc and Irish Agreement Board approvals.In addition, Qual-PEX pipe is fully approved in France and the USA, where it is inwidespread use in Underfloor/Radiant Heating systems.

As well as being a leading edge manufacturer of pipe for the Plumbing and HeatingIndustry, QPL has developed a true expertise in the design of heating systems tomaximize the potential of Qual-PEX pipe. Many systems are straight-forward and aresimply adapted from traditional metal pipe plumbing systems, but new methods ofheating buildings are now being opened up with the use of thermoplastic pipe inapplications such as wall heating, ceiling heating and most especially UnderfloorHeating.

QPL has a design team second-to-none specialising in Underfloor Heating systems.These engineers have extensive experience in Heating system design, CAD packagesand Building Services which they apply to each individual project to produce a uniquesystem design specification for the client.

As this industry grows so does the expertise and the experience of the design team inQPL. This manual has been produced to encapsulate some of the current knowledgeand thinking behind the Qual-PEX Underfloor Heating System Design for the benefit ofthe specifiers and installers of Underfloor Heating Systems.

This manual does not purport to address all design, installation and safetyconsiderations associated with the use of Qual-PEX Pipe for Underfloor Heating. It isthe responsibility of the user of this manual to determine the viability and safety of eachindividual application and ensure its compliance with local building regulations. Shouldmore information be required, please contact the first class design team at QPL, whowill be more than happy to assist.

GARRY D HORGANCHAIRMAN, QUALITY PLASTICS LTD

Quality Plastics Ltd (QPL) was established in 1970 as a pipe extruding company. Over the years thecompany has gone from strength to strength and now employs over 100 people in both Ireland (QualityPlastics Ltd) and the UK (Qual-Plumb (UK) Ltd). The range of products supplied by QPL is continuing toexpand through an ongoing programme of product research and development. One of the many productsmanufactured by QPL is Qual-PEX cross linked polyethylene barrier pipe, which is used widely forplumbing and heating systems. In addition to the markets in Ireland and the UK, Qual-PEX barrier pipe isalso distributed to France, Spain, Norway and the USA.

In 1996, the Qual-PEX Underfloor Heating department was set-up and has grown to a work force of 6dealing with quotations, queries, design and technical support both in-house and on-site. The serviceprovided by this department includes design and supply of the underfloor system (via a Qual-PEX pipestockist). The key feature of this quality underfloor heating system is Qual-PEX 15mm Barrier pipe, whichis BS 7291, Class S approved and carries a 25 year guarantee.

Design Service

At QPL, the heating engineers design a system to meet the client’s requirements by working inconjunction with them. By entering in the key factors to a specialist software package, QPL’s specialistengineers can determine the heat requirement for each room / zone to produce optimum comfort levels.The QPL underfloor heating department have been working hard implementing constructive changes inline with the QPL continual development plan and have come up with a new combination of materials andcontrols which will provide a reliable and cost effective control at a very competitive price. In making thesechanges the design time has been improved and QPL now provides the most technically advancedsystems at a very competitive price.

The QPL design engineers produce a pipe layout drawing for every individual project showing theconfiguration of each of the loops and the position of the manifold. A typical pipe layout drawing is shownon the following page.A full design specification is produced detailing the design criteria and guidelines from the initial processof installing the pipe to the commissioning of the system and controls layout. This design is alwaysproject specific and each design is tailored to suit the client’s requirements.

To obtain a quotation simply forward a good quality set of drawings to Quality Plastics Limited, eitherdirectly or via a plumbing contractor / Qual – PEX stockist.

QPL Ireland White’s Cross • Cork• Ireland T: +353-21-4884700 • F: +353-21-4884706E-mail: qpl@qpl.ie • Web: www.qpl.ie

Pipelife UK Depot 13 Saxon Way East • Oakley Hay Industrial Estate •Corby • Northants • NN18 9EY.Tel: 0845 2419 490 • Fax: 0845 2419 491Email: info@pipelife.co.uk • Web: www.pipelife.co.uk

Quality Plastics Ltd. - background

quality plastics ltd. - background06

EVOH OxygenBarrier Layer

Outer Layer of Crosslinked Polyethylene

Adhesive Layers

Inner Layer of Crosslinked Polyethylene

QUAL-PEX BARRIER PIPE COMPRISES 5 LAYERS:-inner and outer layers of crosslinked polyethylene (PEX)- two thin polymer adhesive layers- central EVOH (Ethylene Vinyl Alcohol polymer) barrier

layer

07

guarantee & products08

ContractQPL accepts full responsibility for the design ofthe system and the specification and supply ofmaterials. As an added re-assurance, for thecustomer, QPL carries professional indemnityinsurance to cover all designs.

The responsibility for system installation,commissioning and ultimate system functionrests with the Heating Contractor/Installer.

SubmittalsProduct Data: Quality Plastics Ltd will providerelevant data for manufactured products andassemblies including installation recommendationsand diagrams. Operating and MaintenanceInstructions: Includes manufacturer's descriptiveliterature, operating instructions, maintenanceand repair data, and parts description.

WarrantyQuality Plastics Ltd, provides a twenty-five (25)year manufacturer's warranty for Qual-PEX pipewhen used in underfloor heating systems andone (1) year manufacturer's warranty forancillary components supplied by QPL providedthe system has been installed and tested perQPL instructions.

Quality assuranceGeneral Requirements: Materials shall bedelivered in their original, unopened packages tothe Qual-PEX stockist.Installer's Qualifications: Installation ofQual-PEX UFH System shall be by a competentinstaller, ideally approved by Quality PlasticsLtd.

Materials:QPL supplies a complete radiant heating systemwhich includes : Distribution manifolds containing supply andreturn outlets with balancing adjustment andflow meters for each circuit.

Pipe: Underfloor circuits shall be installed using15mm Qual-PEX barrier cross-linkedpolyethylene. Qual-PEX is manufactured byQPL and is to be installed in complete accordwith manufacturer's instructions.Qual-PEX barrier pipe is manufactured with aninternal EVOH oxygen diffusion barrier allowingno more oxygen permeation than 0.1 gram percubic meter, per day (0.1g/m3/d).

Controls: QPL also supply the thermostaticmixing valve and pump required for an UFHsystem and full system control including digitalroom thermostat, actuator heads and wiringcentres.

Pipe Fixing System: QPL also provide variousfixing systems to cater for different methods ofpipe installation.

Primary boiler loop and circulating pump: Primary circulating loop (products) shall besupplied by others with sufficient system waterflow to provide boiler supply temperaturebetween 60.0ºC to 82.2ºC with an 11ºCmaximum temperature drop between primaryloop supply and return piping.

Floor Structure: It is the responsibility of theBuilding Project Manager/ Floor screedContractor to ensure that all floor structurescomply with standard codes of practice andBuilding regulations.

Quality Plastics reserves the right to changecomponents without prior notice.

guarantee & products

overview 09

Modern underfloor heating systems are clean,comfortable, and economical to run, virtuallymaintenance free and offer tremendous energysaving potential.

Conventional heating systems (using convectorradiators) provide warmth within a space orbuilding by heating the air in the room. Bycomparison, UFH transfers heat from a verylarge surface area, which is only slightly warmerthan the room. Floors are warmer and the floorto ceiling temperature and humidity levelsremain more constant producing a morecomfortable environment for occupants. Theheated floor operates at low temperatures andwill not cause convection drafts or circulation ofdust within the room.

The floor surface temperature required isusually quite low and very close to the actualroom temperature and always below 29ºC inoccupied areas to achieve an acceptabledegree of comfort. It is essential however, thatfloor coverings do not provide too great adegree of insulation or the heat in the UFHsystem may not be able to raise the roomtemperature to its design level.

The basic operation of a water-based underfloorheating system is pipe embedded within aconcrete screed with warm water circulatingthrough the pipe work allowing for the gradualheating of the screed and eventual emitting ofheat from the floor into the room. The heat isconcentrated where it is most needed for humancomfort and energy efficiency.

It is quite common to have a mixed system inone building where underfloor heating is usedthroughout the ground floor and radiators areused in the upper floors / bedroom areas, whereonly sporadic heat is required. Both systems canbe operated off one boiler, but will need differenttime controls due to the different responsetimes. The only exception to this is where UFHis required for a single room. In this case QPLhave a special pump / control unit availablewhich allows a single underfloor heating circuitto be connected to a radiator heating system.

overview

The major benefits of a Qual-PEX underfloorheating system are:

• Comfortable, even temperature throughout

• Efficient on fuel due to lower operating temperatures

• Healthier environment with less dust being circulated

• Safer—no hot panels or dangerous hard edges

• No restrictions on interior design layout

• Low maintenance

• Maximum usable floor spaces

• Excellent value for money

floor construction materials10

With any solid floor construction, the followingfloor materials need to be used andincorporated to construct a solid and effectivefloor for the laying of any underfloor heatingsystem.

ScreedA screed is used as a non-structural finish to aconcrete floor. It is not a hardwearing finish andmust have a floor finish on top of it. The purposeof the screed is to provide a flat level surface.

Pre-mixed screed.Pre-mixed screeds have in-built retarders toallow the whole day to lay the screed and fiberre-inforcement, which will increase the strengthof the screed.

Pumped ScreedsThese fall into 2 categories

Semi-dryHere the pre-mixed semi-dry screed is pumpedalong a flexible pipe to be discharged into theroom - saving the barrowing, and possibility ofdamage. Very useful if screeding upstairs.

Liquid screedHere the screed is pumped in full liquid form -making it very easy to move around. It is a quick system to lay, but there is morepreparation, to make sure there are no leakagepoints at the edges.

ConcreteWhat is concrete?A mixture of a cement, gravel and sand, gaugedwith water, which may contain admixtures.

How long should it take to set?Dependent on temperature and mixspecification 2-4 hours for initial set, 24 for finalset depending on the cement type, and thepresence of retarders or accelerators;approximately 90% of final strength will beachieved within 28 days.

What are the mixes?Typical mix is 1:3:6 of cement, sand, aggregate. The size of aggregate is important - too big andall the voids means more cement is needed, toosmall and strength reduces.A stronger mix would be 1:2:4

Proportions are by volume not by weight.

AdditivesThere are many additives that can be used withMortar, screed or Concrete, the most usefulones being:

Retarder Used to delay the on set of first set by up to 12hours

Rapid Hardener This will bring on the first set in less than anhour; this is useful in frosty weather when youneed the first set to happen before frost arrives.

A typical screeded floor structure will consist ofthe following:

• Floor finish• Screed or concrete layer• Edge insulation• Underfloor heating pipe• Floor insulation• Floor slab or sub floor

floor construction materials

floor construction materials 11

Insulation The most important energy saving measure onecan make during the design of a new home is toallow for large levels of insulations enclosing theenvelope of the building (floors/walls/roof).Insulation is expensive but saves money in thelong term. Floor insulation is usually positionedabove a layer of hard core and below theconcrete slab and floor screed as can be seenbelow.

For underfloor heating this insulation layershould be placed directly below the screedcontaining the underfloor pipes and above thehard core and concrete slab as can be seenbelow.

The insulation required is dictated by BuildingRegulations (Minimum standards). In recenttimes these standards have changed severaltimes in an effort to improve the energyefficiency in new dwellings. The most recentchange (01-07-08) has improved efficiency by40 % from previous standards; it is alsoexpected to be further improvement by 20 % in2010. This improvement of 40 % is a wholebuilding assessment and takes into accountbuilding fabric, heating system, and renewabletechnologies.

According to these regulations the maximumfloor U-Value required for underfloor heating is0.15 W/m2K (an improvement from 0.25 W/m2Kon previous standards). These regulations onlyapply to the ground floor. The thickness ofinsulation required to achieve this combinedU-Value will vary depending on the floorstructure/area/perimeter and the thermalconductivity of the insulation.

floor construction materials12

The graph below shows how the insulationthickness varies relative to it’s thermalconductivity and the ratio of the dwellingsexposed parameter to its area (P/A). This graphhas been compiled assuming a standard slabon ground floor construction with a total U-Valueof 0.15 W/m2K.

Given the P/A ratio and either the thermalconductivity of the insulation or the thicknessavailable for floor insulation the unknownquantity can be determined.

Thermal Conductivity example:

Area A = 150 m2Perimeter P = 45 mThermal conductivity 0.023 W/mK

First calculate the P/A ratioP/A = 45/150 = 0.3

The remaining unknown can be determinedfrom the graph

Thickness = 106mm

Thickness Available example:Area A = 150m2Perimeter P = 75 mThickness available 100 mm

First calculate the P/A ratioP/A = 75/150 = 0.5

The remaining unknown can be determinedfrom the graph

Thermal Conductivity = 0.019 W/mK

On average from between 100mm and 120mmof insulation with a thermal conductivity valueof 0.022 W/mK will suffice (P/A range between0.3 – 0.6).

As mentioned previously further improvementswill be made to the building regulations in 2010,however Quality Plastics expects the combinedU-Value for floors with underfloor heating toremain the same.

160

140

120

100

80

60

40

20

0

P/A 0.1 P/A 0.2 P/A 0.3 P/A 0.4 P/A 0.5 P/A 0.6 P/A 0.7 P/A 0.8 P/A 0.9 P/A 1.0

0.018 0.019 0.02 0.021 0.022 0.023 0.024 0.025

Insulation Thermal Conductivity (W/mK)

P/A RatioLarge House Small Extension

Insu

lati

onTh

ickn

ess

(mm

)

Insulation Thickness = 100mmP/A = 0.5

Conductivity 0.019 W/mK

Conductivity = 0.023 W/mKP/A = 0.3Insulation Thickness ≥ 106 mm

Thermal Conductivity / Thickness

floor construction materials 13

Insulation Installation

• The insulation board is simply laid loose over the concrete sub floor. Board joints should be tightly butted, staggered, and laid to a break-bonded pattern.

• Good practice would be to tape the board joints together to prevent any screed seepingthrough and “floating” the insulation boards. The floor slab should be uniformly flat withoutany steps or gaps to provide continuous bearing support to the insulating board.

• The use of 25mm edge insulation is also recommended. The edge insulation is laid along any external wall and should be of sufficient height to accommodate the total depth of screed to be poured.

• Edge insulation prevents any heat escaping into the wall and thermal bridging occurring.

Reasons for insulationA house that is properly and sufficiently insulated:• Is more energy-efficient, and therefore,

saves the homeowner money. • Does not need extra effort and expense to

keep it comfortable – insulation is permanent and usually does not require maintenance.

• Has warmer floors and temperatures are more uniform throughout the house.

Damp Proof membrane

When using a damp proof membrane the following points should be adhered to:

• The DPM is usually positioned between thehardcore and sub-floor with a sandblind to protect the membrane from damage.

• Where DPM is laid below concrete, it should be at least 1200 gauge material laid with joints sealed.

• Avoid sharp projections and damage to the membrane

• Take care not to damage the DPM at the junction with the wall DPC when power floating the slab.

floor structures - types14

It should be possible to install an underfloorheating system into any normal floor withoutrequiring significant changes to the floorstructure. However, there are some basicrequirements that need to be adhered to:

• The temperature within the floor structure must not be raised to a level at which the strength and characteristics of the floor are adversely affected.

• Insulation of adequate thickness and U - value must be provided to limit the downward heat losses from the floor.

floor structures - standard

screed above sub-floor (tile finish)

• The floor finish must have a sufficiently low resistance to the passage of heat to enable the heat to be emitted into the room or space above.

• Consideration must be given to any other services contained within the floor structure that may be affected by the increased temperature.

The three most common type of floor construction are:• Screed above sub-floor• Screed above pre-cast slab• Suspended Timber Floor (joist)

where to use

15floor structures - screed above sub-floor

Screed above a Sub-Floor

• The hardcore should be well compacted and finished with not less than 25mm of sand to protect the DPM.

• This DPM is positioned on top of the sand which combines with the DPC to prevent moisture infiltration.

• Next a concrete sub-floor is poured to engineering specifications and allowed to dry.

• An insulating layer must be installed below the plane of the pipe. Edge insulation must be installed around the perimeter or external walls up to finished floor level. Edge insulation permits the free expansion of the floor screed.

• Insulation boards should conform to currentbuilding regulations. On average from between 100mm and 120mm of insulation with a thermal conductivity of 0.022W/mK will suffice (P/A range between 0.3 - 0.6). See page 12 for further details.

• The insulation must be laid in a staggered format, any joints taped together to preventscreed slipping into the cracks and care must be taken not to damage the boards during installation.

• The rapid rail lengths are laid at 90º to the direction of the pipe and are fixed in position using the red fixing clips. Fixing clips are used at 400mm centers along the length of rapid rail.

• The rail is installed at approximately 1000mm intervals and should span the width of the zone.

• The rail can be snapped to length when required.

• Pipe spacing is easy to maintain using rail as pipe grooves are all 25mm apart.

• 60mm green clips are also used to fix the pipe directly to the insulation layer at bends in the loop pattern.

• Alternatively, the pipe may be cable tied to a steel mesh laid over the insulation.

• A normal floor screed (4:1) sand and cement may be used with underfloor heating. The minimum depth of screed above insulation is 65mm and the practicable maximum is 100mm. Care should be taken that the screed is laid from planking to protect the pipe from damage. If ready mix concrete is being used then it should be mixed with a 10mm pea gravel base.

• To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand (during the pour) until second fixing.

• The finished floor covering should not be fitted until the screed has completely dried out. As a rule of thumb, allow a minimum of 1-week drying time per 25mm screed.

floor structures - screed above sub-floor16

thin screed method above sub-floor (solid wood finish) where to use

floor structures - screed above sub-floor 17

Solid wood floor above a sub floorusing 50mm screed.

• Where an underfloor heating system is to be installed below solid wood flooring, special design considerations should be taken into account for the floor structure. The surface of the floor structure should beflat and even. The concrete sub-floor should be set and cured.

• 100mm -120mm x 50mm battens should belaid on top of the sub floor at 400mm centers.

• 100mm -120mm high-density polyurethane insulation should be cut to fit in-between the battens (see page 12).

• The 100mm -120mm x 50mm battens are then counter battened with 50mm x 50mm battens at 400mm centres. These battens should stop short to allow the pipes turn.

• Qual-PEX 15mm barrier pipe is fixed between the counter battens at the correct spacing using fixing rail and clips.

• To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-barand allowed stand (during the pour) until second fixing.

• A lean mix of 8:1 sand and cement is installed between the counter battens, and finished flush with the top of the battens.

• The mix should be just wet enough to reactand bond, but dry enough to minimise the additional load on the structure.

• The screed is allowed to dry out completelybefore the finishing floor deck is installed using the battens as fixing points. (allow 1– 2 weeks drying time).

floor structures - screed above pre-cast slab18

screed above pre-formed insulation (tile finish)Only to be used in intermediate floors such as apartment developments on pre-cast concrete slabs

Heating and Domestic Hot Water Systems for dwellings-Achieving compliance with (TGDL) Part L 2008.

Section 7. Underfloor heating systems page 57.

“Intermediate floors with heated rooms below, complying with both Part L and Part E of the Regulations, should have aseparating layer of system thermal insulation where the minimum thermal resistance is given as not less that R = 0.5 m2 K/W (U-Value of total floor = 1.33W/m2K)”

where to use

floor structures - screed above pre-cast slab 19

Screed above pre-formedInsulation

• The pre-cast slab must be swept clean andbe free from dirt and debris before any work is carried out.

• Edge insulation must next be installed around the perimeter or external walls up tofinished floor level. Edge insulation permits the free expansion of the floor screed.

• Place the pre-formed Insulation board down. This board contains “noggins” which hold the underfloor pipe in place.

• The insulation must be laid in a staggered format, any joints must be taped together toprevent screed slipping into the cracks and care must be taken not to damage the boards during installation.

• Pipe spacing is easy to maintain using pre-formed insulation as pipe grooves are all 200mm apart.

• A normal floor screed (4:1) sand and cement may be used with underfloor heating. The minimum depth of screed above insulation is 65mm and the practicable maximum is 100mm. If ready mix concrete is being used then it should be mixed with a 10mm pea gravel base.

• To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-barand allowed stand (during the pour) until second fixing.

• The finished floor covering should not be fitted until the screed has completely dried out. As a rule of thumb, allow a minimum of 1-week drying out time per 25mm screed.

floor structures - screed above pre-cast slab20

screed above multi-reflective insulationOnly to be used in intermediate floors such as apartment developments on pre-cast slabs

where to use

Heating and Domestic Hot Water Systems for dwellings-Achieving compliance with (TGDL) Part L 2008.

Section 7. Underfloor heating systems page 57.

“Intermediate floors with heated rooms below, complying with both Part L and Part E of the Regulations, should have aseparating layer of system thermal insulation where the minimum thermal resistance is given as not less that R = 0.5 m2 K/W (U-Value of total floor = 1.33W/m2K)”

floor structures - screed above pre-cast slab 21

Screed above multi-reflectiveInsulation

• The surface of the slab should be swept clean and free from any debris.

• A suitable layer of thin multi-reflective insulation is installed over the whole surface area.

• The insulation is turned up at the perimeter to act as edge insulation and separate the screed from the wall.

• A steel mesh of grade A 142 or similar is laid on top of the insulation and the Qual-PEX 15mm barrier pipe is fixed to the mesh using cable ties.

• To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-barand allowed stand (during the pour) until second fixing.

floor structures - suspended timber22

floor structures - suspended timber

Underfloor heating in suspendedtimber floors

Underfloor heating systems may be installedsuccessfully under suspended timber floorsprovided that the floor is constructed to suit theapplication. Therefore it is essential that planning begins at an early stage in the project

dry method (diffuser plate method for suspended timber)

and the building contractor is informed of theconstruction requirements for the underfloorheating. The main consideration is the additional structural load.

There are two main methods of this type offloor construction:

• dry method• wet method

where to use

floor structures - suspended timber (dry) 23

Dry Method (Aluminum Diffuserplates)

• This method can be used in projects wherethe added weight of a thin slab is undesirable. The response time of this type of system is comparable with radiator systems, however good levels of insulation directly beneath the diffuser plates are essential for efficient operation.

• Aluminum double plates measuring 1000mm x 400mm are used to spread the heat evenly across the underside of the floor deck.

• The insulation required will depend on the floor level. For ground floor level a U-Value of 0.15 W/m2K (see page 12) is required, resulting in between 100mm and 120mm ofinsulation. For intermediate floor levels the U-value of 1.33 W/m2K (see page 18) is required resulting in only a thin layer being used.

• Fix the diffuser plates on one side only of the joist to allow the plates to expand freelywhen the floor deck is laid on top.

• The plates are fabricated to ensure the Qual-PEX pipe is tightly encapsulated only after the deck is laid.

• There should be a gap of approximately 15mm - 20mm between the individual plates.

• The line of the plates should terminate 300mm from the end wall of the zone to allow the Qual-PEX pipe to be returned at aradius of 200mm.

• The joints should be notched at each end of the room to allow access for the underfloor pipe.

• To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-barand allowed stand until second fixing.

• If required a thin plywood sub-floor is laid above the diffuser plates to allow for the fixing of a floating floor (tile or carpet).

floor structures - suspended timber (wet)24

wet method 30mm -50mm screed where to use

25floor structures - suspended timber (wet)

Wet Method

• Note that this method of using a biscuit screed (8 : 1 sand and cement) will add considerable weight to the structure, particularly before it dries out. Ensure that your engineer is aware of the added weight on the floor joists so that they may take intoaccount the design of the floor structure.

• Attach a set of 50mm x 50mm battens to the side of each joist running the same direction as the joist.

• Cut a light layer of 10mm – 15mm plywood to fit on top of these battens to allow a layerof insulation to be fitted.

• The insulation required will depend on the floor level. For ground floor level a U-Value of 0.15 W/m2K (see page 12) is required, resulting in between 100mm and 120mm of insulation. For intermediate floor levels the U-value of 1.33 W/m2K (see page 18) is required resulting in only a thin layer being used.

• The rapid rail fixing system is now cut and placed between the joist at 1m intervals.

• The joist should be notched at each end of the room to allow access for the underfloor pipe.

• To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand until second fixing.

• A lean mix of sand and cement (8:1) is poured between the joist and finished off flush with the top of the joist. The mix should be wet enough to react andbond, but dry enough to minimise the additional load on the structure.

• The screed is allowed to dry out completely before the finished floor deck is installed, (allow 1 – 2 weeks drying out time).

• If required a thin plywood sub-floor is laid above the diffuser plates to allow for the fixing of a floating floor (tile or carpet).

floor finishes26

Most floor finishes are able to cope with an UFHsystem if the underside of the floor is wellinsulated. However the maximum temperaturelimits, specified by the floor manufacturer mustbe checked against the maximum design floorsurface temperatures for a given room or space.Some finishes which are considered to be veryhard wearing are actually quite temperaturesensitive and have similarly low surfacetemperature limits. Many vinyl tiles and plasticfloor coverings fall into this category.

floor finishes

Carpet Flooring

Most fitted carpets can be good transmitters ofheat. It is important however to make sure thatthe underlay is suitable for UFH and has a lowTOG value. The TOG values of carpets and underlaysshould be available from the respectivemanufacturers. The TOG rating of an underlayshould not exceed 0.5. The maximum TOGvalue of carpet should be 1.0 – 1.5.

Although there are many synthetic types ofcarpet underlay, only rubber types should beused over underfloor heating systems. Rubberunderlays come in two types: slab or waffle. Thequality of the rubber is important, the cheaperproducts use fillers and have oily compoundsthat can leach out over time when heat isapplied resulting in an underlay that will degradeover time. A good quality underlay will usuallyhave a lifetime warranty. Such underlays aregenerally quite satisfactory with underfloorheating.

Tog Value

0.0

0.5

1.0

1.5

Thermal Resistance

0.0 m2K/W

0.5 m2K/W

0.10 m2K/W

0.15m2K/W

Typical Examples

Ceramics, stone, slate, marble

Synthetic blocks, linoleum, laminates

Carpets, underlays, 13mm hardwood, parquet

Deep pile carpets, 22mm hardwoods and laminates

A typical TOG / R-value chart is shown below:

floor finishes 27

Tiled Floor

Ceramic tile floors work well with UFH as theyprovide minimal resistance to heat. To preventany cracking occurring it is always advisable touse a suitable tiling adhesive that is specificallydesigned to work with underfloor heating.

Timber floorings

Underfloor heating installed below a finishedwood floor can provide both a comfortable andefficient heating system. However, warmingwood flooring can present certain unique designand installation considerations in order tominimise possible shrinkage of the flooring.With few exceptions, the maximum designsurface temperature below wood flooring shouldnot exceed 29ºC (always check with the timbermanufacturer if this limit is sufficient).

Hardwoods (e.g. oak, maple) are a better choiceover softwood (e.g. pine) as they have lowerresistance values and therefore do not suppressthe heat rising from the slab below.Pre-finished floating wood floor systems orfloating floors are an excellent alternative to traditional wood flooring, because of simplerfloor construction and ease of installation.

Where possible use boards narrower than70mm. The narrower the board the lessshrinkage that will occur. If wider boards aredesired, lower surface temperatures should bemaintained, while ensuring that the resultinglower heat outputs can provide the room heatingrequirement.The best way to minimise changes in woodmoisture content is to ensure that the wood isproperly acclimatised to the conditions that it willsee in service, and finish the wood floor with alow permeability coating.

28 floor finishes

Hardwood Flooring

Hardwood flooring has many advantages,healthier, easier to clean, but it is expensive andcan be prone to scratches.

There are 4 main types of hardwood flooring

• Solid wood • Veneer• Laminated construction solid wood• Laminate

Solid Wood Generally these should be fixed down securely,the neatest way being by setting battens into thescreed and then screwing the individual woodenplanks to this batten. No air gaps are allowed.

VeneerHere the substrate is typically MDF or similar,with a thin veneer of hardwood. These are fullyfinished and although inexpensive, areunsuitable for areas of heavy wear, as theycannot be re-sanded.

Laminated Construction solid woodConsists of floor strips where the base is madeof layers of a multi-cross core, topped with awear layer of expensive hardwood. These wearlayers can be up to 7mm thick, which gives thesame number of re-sanding operations as a onepiece solid wood construction.Generally these are not fixed, and are laid asfloating floors.

LaminateThere are several versions, based on a print orphotographic film being stuck onto the surface ofa composite board such as MDF.Due to the thinner section, typically around13mm, they are particularly useful for overunderfloor heating.*note:Wood floors expand and shrink accordingto moisture conditions.

Moisture content

High humidity or moisture levels must beprevented before, during and after a wood floorinstallation. The concrete floor must be fullycured prior to any wood flooring installation andthe heating should be operational for one weekprior to the installation. This will help to establishboth temperature and moisture at or nearoccupancy levels.

The installation of the wood flooring should notproceed until the buildings moisture content isbelow 10%. The flooring material (approx 8%kiln dried) should be placed in the room in whichit is to be installed for a minimum of 2 weeks atconditioned temperature and moisture levels tofully acclimatise it to its environment. If system operation has been used to achieverequired room temperature and moisture levels itmust be turned off during the flooring installationand temporary heat provided as necessary. Theheating system should not be turned on againuntil the floor staining and sealing materials arefully dried, typically 5 – 7 days.

29installation procedures for the pipe loops

installation procedure for the pipe loops

• Start by mounting the manifolds in the chosen location and installing the rapid rail fixing system over the insulating layer.

• For each zone refer to the zone list which gives details about pipe circuit lengths and flow rates. Also refer to the pipe cutting list to establish the precise cut to make from each coil of pipe. One end of the pipe coil is connected to the manifold and the installer begins by working towards the zone.

• If possible two people should carry out the installation work, one uncoiling the pipe while the other clips it to the fixing rail or onmesh. Alternatively a pipe un-coiler may be used which allows one man to lay the pipe.

• The flow pipe is fixed to run around the outside wall at approx 100mm from the perimeter.

• The loop is installed according to the custom designed pipe spacing and pattern back to the manifold.

• Although the design spacing of the pipes may produce a bend radius which is less than the minimum bend radius

recommended for Qual – PEX (6-8 times the pipe diameter) this minimum radius should be maintained by forming a keyhole shape bend where necessary.

• On completion of the circuit, the end of the loop is connected to the return port on the manifold, and is clearly labelled.

• When all the loops are installed, visually inspect the pipe work for any possible damage that may have occurred during the installation procedure.

• To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand (during the pour) until second fixing.

• This pressure test should be maintained while the screed floor is being poured and should be checked at regular intervals to ensure that no damage has been caused tothe pipe loops

• *Never leave a pressure test running on an exposed site where there is a risk of freezing conditions. In such circumstances use air or nitrogen gas to pressure test the system.

installation procedures for the pipe loops30

Damage to the pipe during installation : Repair

If you have damaged the pipe and need to makea repair to it, follow the step by step instructions:

• Cut out the damaged section of pipe (approximately 50mm at either side of the damaged pipe). QPL recommends the use of a pipe cutter specifically designed for plastic pipe.

• Push the Qual-PEX 15mm support insert into the pipe—it will assist in re-rounding the pipe after the cutting action. The insert will support the pipe in the joint.

• Connect the pipe work together using a suitable 15mm compression or push-fit fitting.

• Put some fine sand underneath the pipe work to act as bedding.

• Wrap the completed fitting in gauze to ensure a tight seal, to prevent the screed from coming in contact with the fitting.

• Lay the fitting on the sand and cover with screed.

Pipe in transit to other heatedareas

Such pipe runs deserve special attention, asthey rarely form part of the heating to the roomthrough which they pass, and can distorttemperature control considerably. For thisreason pipes are usually spaced 50mm apart, togive the least floor surface area and are locatedbeside the skirting board for the least impact. Itis also recommended to use corrugated ductingand to sleeve every second pipe to reduce theheat output in areas where pipes may bebunched together i.e., to reduce hot spots.

Qual-PEX should be sleeved in ducting whenpassing through walls, expansion joints andwhere it enters and exits floor screeds. The useof ducting is also recommended to limit thermalexpansion in areas where the pipe runs are veryclose together such as near manifold positionsand to prevent excessive hotspots in this area.Ducting may also be used in areas where pipesare running under kitchen units or other fixtureswhere heat emission is not desired.

Proximity of UFH pipe work toother servicesModern service systems can include servicepipes run in flexible conduits within the insulationlayer beneath the floor to travel relatively greatdistances uninterrupted. It is necessary toensure that the UFH system does not adverselyaffect the other services within the dwelling.Where service pipes are run in conduit below anunderfloor heating system, protection of coldwater pipes is mandatory.Electrical power cables and conduits must alsobe protected against overheating.Provision shall be made, where necessary toallow for expansion and contraction of the buriedpipe eg., where gas pipes are laid close to heat-ing system pipes. Good practice is to lay the gaspipe beneath the underfloor insulation prior toany screed being poured.

boiler considerations 31

Boiler noise : boilers with high efficiency usuallyhave a low water content and require aminimum flow rate to be maintained through theheat exchanger to ensure that the heat can beremoved quickly enough. Small systems whichdo not require a high circulator duty, canoccasionally cause noise problems if the boilerrequirement for a minimum flow rate isoverlooked. In such cases, an automatic bypassvalve should be fitted so that the minimum waterquantity can flow through the boiler withoutrelying on circulation through the radiators. Inthese circumstances the circulator must becapable of satisfying the duty on both thesystem and bypass.

• After the room by room heat loss calculations has been performed, the first component to be considered is the boiler. The boiler must be sized so that the output is marginally greater than the calculated total heat loss. Auxiliary loads such as domestic hot water, radiators and supplementary heating (towel rail etc) must be considered and added to the boiler load.

• Ensure that the boiler is sized to meet the requirements of the highest seasonal loads of the building.

• It is recommended that multiple boilers be used in larger systems. This will improve overall efficiency by permitting the shutdown of boilers when full heat output is not required. Multiple boilers also provide back-up capacity in case one of the boilers fail.

• Boiler efficiency is greatly affected by boilerwater temperature. High water temperatureincreases the opportunity for on cycle and off cycle losses. With high water temperature on cycle losses occur becausethe heat is transferred from the flue gases to the water. This means that more heat willescape up the chimney. Furthermore, a higher water temperature increases boiler jacket and distribution pipe losses in off-cycle.

boiler considerations

• Most boiler manufactures specify a minimum return water temperature, flow rate and temperature rise. In a boiler, whenfuel is burned, water vapor, carbon dioxide and heat are produced.

• If the flue side surface of a cast iron boiler drops below the dew point (45ºC - 50ºC) the low return water temperature will causewater vapor to condense on the surface of the cast iron. Start-up condensation is common and usually presents no problems.However continuous condensation will cause the surface of the boiler to corrode. This will significantly shorten the service lifeof the boiler. Therefore the system pipe work should be configured to maintain a high back end temperature at all times. In addition to the potential problems of corrosion, low back-end temperatures will significantly reduce the efficiency of the boiler by requiring it to be on for long periods of time to heat the return water back up to the supply water temperature.

Primary/Secondary Distribution System

There are many different pipe layouts used incentral heating systems, but the most practicaland efficient piping system for multi-zonedunderfloor heating systems is the primary/secondary system. This type of installation hasbeen standard practice in commercial buildingsfor many years and offers great versatility interms of efficient operation, ease ofmaintenance, controllability, and easyinstallation. This system will ensure high backend temperatures at all times.

The system operates in the following way:

• A boiler circulates water around the primaryloop whenever the boiler is switched on. The primary pump ensures a continuous and constant flow rate through the boiler irrespective of the overall demand.

boiler considerations32

Because the secondary circuits have been connected using closely coupled tees the primary pump will not cause circulation to occur in the secondary circuits (the water will always take the shortest route back to the primary pump inlet).

• The secondary circuits are also individually pumped(zone pumps) and the operation of any of these zone pumps will have no effect on the other circuits. All this makes it easy to plan and install the distribution system using domestic size pipe and equipment.

• Secondary circuits requiring different water flow temperatures can be linked into the primary loop but it is important to connect the circuits requiring the hottest supply water upstream of the lower temperature circuits.

Pipe sizing and layout:

• The primary pump will be designed to deliver the sum of all individual flow rates inthe secondary zone against the head loss in the primary circuit.

• The diameter of the primary pipe work will be (at least) one size larger than the diameter of the secondary connections. All necessary safety equipment will be connected to the primary circuit and the relevant positions of these basic components will ensure that the system operates without any air related problems. The flow and return connections to the secondary circuits will be spaced at a distance of not more that 15cm C/C with a minimum of 20cm of straight pipe upstreamand downstream of these connections.

Position of Primary pump and Expansionvessel/feed:

These components have an importantrelationship to each other in a well-designedheating system. The connection betweenexpansion vessel and the system piping is thepoint of no pressure change (neutral point) andits pressure remains constant regardless ofwhether or not the pump operates. When theneutral point is located close to the suction sideof the pump then the pump suction pressure isfixed and the differential pressure will appear asan increase above the static.

Therefore the system operates under a positivepressure which provides the best possiblecondition to eliminate air. The neutral point alsoprovides the best location to connect the makeup water for the system as it is the only place inthe system where the pump operation does notaffect system pressure. A pump fitted on the flowfrom the boiler provides a point of low solubilitybetween boiler and pump, the optimal locationfor an air eliminator where all the air will beeliminated to ensure the system will be air free.

boiler considerations 33

The main advantages of the system are:

1. On/Off control to zones using zone circulators (pumps).

2. Allows independent time and temperature control of different zones.

3. Permanent by-pass circuit ensures continuous flow through the boiler, maintaining a high back-end temperature at the boiler.

4. The relative positions of the circulators and the feed and pressure vessel ensure a positive pressure on the system at all times. This will assist with air elimination and protect the pumpsfrom problems of cavitation.

5. Allows pumps and controls to be located in one area, simplifying installation.

The figure shows a typical primary/secondary system for an installation with aradiator circuit, a domestic hot water circuit and an underfloor heating circuit.

system components34

Manifolds

Quality Plastics manifolds provide the flexibilitynecessary to design and commission theoptimum system for any given project. Thepressure drop across the manifold will limit thenumber of loops a single manifold can serve toa maximum of 12. All manifold distributionheaders and accessories are nickel plated.Thepre assembled manifold comes complete with :

• Lockshield valves with individual flow meters

• Thermostatically controllable valves with protection caps on the return

• 2 no. blanking plugs with o-ring sealing gasket

• 2 no. water drain valves• 2 no. bleed valves• 2 no. metal brackets• 2 no. temperature gauges to observe

supply and return water temperatures.

system components

Location of Manifold

• Locate and mark all different zones on site. To comply with building regulations separate temperature control of living areasand sleeping areas is necessary. This may require the use of separate manifolds.

• Decide on all manifold locations. Manifolds may be split to provide better access within the zone area and reduce any piping congestion in front of the manifold.

• Locate the manifold in a central position within the zone area. Choosing a central location will save on the amount of pipe andmanifold ports to be used.

• Make sure that the manifold will be accessible after construction is complete. Manifolds are often under counters and stairs, in utility rooms or in the hot press / airing cupboard.

• Manifolds should be positioned 300mm to 450mm above the finished floor surface. They can be mounted on walls or studs. If no wall exists simply mount the manifold on a temporary structure during the construction phase.

• The manifold is now in position and ready to be connected to the flow and return from the boiler and the underfloor heating circuits.

• A set of self adhesive labels and tags are provided to identify each circuit on the manifold.

• The flow meter on each port of the manifoldgive a clear indication of the flow through each circuit.

system components 35

Mixing Valves

Thermostatic mixing valves are used if either thetemperature or flow rate of the incoming streamfrequently changes. This valve reacts totemperature changes of the incoming fluids byopening or closing its inlet ports as necessary tomaintain a fixed outlet temperature. Underfloorheating systems require lower temperaturewater (typically 38ºC - 45ºC).The valve supplied by QPL is either a 22mm or28mm Heat guard® UFH Blending Valve. Botharea high flow thermostatic blending valves forunderfloor heating applications.

Features and Benefits

• High flow rates:- 22mm suitable for systems up to 200 sqm. - 28mm suitable for systems up to 300 sqm.

• Superb temperature control. • Quick reaction to supply temperature

changes. • User adjustable between 30°C and 60°C. • Compression type connections for ease of

installation. • Lockable temperature adjustment

mechanism.

22mm mixing valve 28mm mixing valve

system components36

Description :Thermostatic blending valve available with22mm / 28mm compression connections.Suitable for blending the supply and return toachieve a stable system temperature inunderfloor heating systems up to 200 / 300square meters.The 22mm valve comes factory set at 43ºC sothis does not have to be adjusted unless diffuserplates are being used in which case it will haveto be reset to approx. 60ºC. The 28mm versionis set at 30ºC, so it will need to be adjusted formost UFH systems.

Floor Mixing Unit

The Pre-assembled mixing unit (Fig. 1) ismounted on a set of brackets and consists of amixing valve, drain valve, bypass/bypass valve,air vent, and temperature gauge. It is designedto fit directly on to any existing underfloormanifold and allows a standard 6 meter headpump to be fitted (Fig. 2). The unit savesroughly two hours labour during the plumbing ofthe manifold due to only a flow and return pipework been required (no complicated elbows).

Operation:Hot water from the boiler enters the unit from thetop left and is drawn through the mixing valve bythe pump. The mixed water (both boiler andreturn water) is then pumped through the flowmanifold (bottom right). The majority of the water

returned from the underfloor circuits will flowback into the mixing valve, the remainder ofwhich will flow through the bypass and return tothe boiler. The lower section of this unit isdivided into two isolated sections; mixed waterwill be pumped into the flow manifold out of theright section while the return water from thebypass will flow out of the left section back to theboiler, there is an internal divide to the right ofwhere the bypass enters the bottom section.

Circulating pump

There must always be a circulating pumpinstalled between the mixing valve and the flowmanifold. This pump ensures fast delivery of themixed hot water to the whole floor area whenrequired. Accurate calculation of the pump dutyis necessary to ensure a correct water flowthough the manifold and pipe circuits. Thestandard pump is a 6m head pump.

Fig. 1

Fig. 2

typical system layout 37

typical system layout

system control38

system control

All heating systems must have proper andcorrect controls to maintain and achievecomfortable living conditions, energy efficientoperation and comply with current buildingregulations.

To get the best results from your underfloorheating system QPL recommends individualroom control. A room thermostat controls theactuator heads that open or close the pipecircuits specific to that area. The roomthermostat system also takes into account allother heat sources including sunshine, bodytemperature and ancillary heat sources (cooker,stove).

There are various types of controls availablefrom boiler controls to air temperature controlsto wireless control. Some controls offer variousadditions such as night setback facility, separatetime and temperature controlled thermostats(i.e. programmable), wet area thermostats.Centralised wiring centre units are also includedto provide complete system control to includeboilers, radiators and domestic water.

Quality Plastics provides a comprehensiveproduct range of these types of controls.

Standard Components

Room / Air Temperature Control.Electronic room thermostat with night reductionmode. Can be used to regulate either the floor(with the addition of a sensor) or roomtemperature or combined. Room thermostatsrequire a 4 core electrical cable for supply.

Programmable room thermostatsFull digital thermostat with 4 user programmesand 9 fixed programmes, powered by 3 batteries(supplied), high accuracy, easy to install andprogramme. They require a 2 core electricalcable for supply.

Wet area probe and sensor boxThe sensor is supplied with 3m of cable andallows the room thermostat to be installedoutside the wet area. Removal of the coverallows the sensor to be used as a floortemperature sensor if preferred.

Hard wired Master modular 4 zone wiringcentreThe master 4-zone wiring centre is a connectingbox with all the main connections for anunderfloor heating system. This is Din rail or wallmounted close to the manifold and connectsroom thermostats to their correspondingactuators. Actuator states (open/closed) areindicated by green LED’s; boiler and pumpstates (on/off) by red LED’s. Includes a volt freecontact to connect to an external power supply.It is possible to add more zones by plugging inSlave connecting boxes.

system control 39

4/6 Zone Slave Wiring CentreThis 4 or 6 zone slave unit is an additionalconnecting box which needs to be connected toa master 230 V wiring centre to add more zonesin order to connect more thermostats and moreactuators.

ActuatorsThe electrothermic actuators are used forON/OFF control of the opening and closing of aparticular underfloor heating circuit on themanifold, (through a switch live by a roomthermostat.) When the blue indicator is visible,the actuator is fully open. Allow approx 2.5-3minutes to energise from the fully closedposition to the fully open position.

4 channel time clockFour switches operated by a clock to control 4separate heating systems independently. Theuser can choose one or more on or off cycles,daily and even weekly cycles depending on userpreference.

Heating Control PanelThis multi-functional panel with L.E.D. lightindicators can incorporate the underfloor heatingsystem for both ground and first floor (ifrequired), domestic hot water and a radiatorsystem. It is extremely versatile due to the factthat it has a 3 or 4 zone capability, priority to hotwater, connection for boiler and primary pump,boiler interlock provision, motorized valvecontrol, connection for time clock and individualzone control provision. It is suitable for pumpedzone systems and has provisions for roomthermostats, thermoelectric actuators andexternal wiring centre units. Quite simply, all theheating system control electrical connections arein one box.

system control40

This whole unit can be placed near the manifoldand the only hard wired connections to it are theactuators and power supply.

RF digital thermostatsThese stats can be used specifically with theradio frequency receiver. Digital displayindicates all temperature and different modes.Controls to receiver by radio transmission.

RF programmable room thermostatsThese stats can be used specifically with theradio frequency receiver to provide separatetime and temperature control for a particularzone. Digital display indicates all temperatureand different modes. Controls to receiver byradio transmission. Also the added benefit ofhaving a time control similar to the time clock :Weekly, daily, hourly.

RF Master modular 4 zone Wiring CentreThe master 4 zone is a connecting box with allthe main connections for an underfloor heatingsystem. Similar in function to the standard hardwired unit.

RF Slave 4/6 Zone Wiring CentreThis 4 or 6 zone slave unit is an additionalconnecting box which needs to be connected tothe master 230 V wiring centre to add morezones and to connect more thermostats andactuators.

RF Single Zone ReceiverThere is also the option of a single zonereceiver, which is designed for use with one RFthermostat only. Ideal for a single zoneapplication.

Wireless / Radio Frequency (RF)Control System

The advantage of using an RF controlled systemis that there is no need for any cables to beinstalled to accommodate any individual roomthermostat. It is ideal for retro-fitting in a buildingor simply for the speedy installation of anunderfloor heating control system. Every radio frequency controlled room requiresits own individual RF thermostat. Each RFthermostat is then allocated an individualfrequency to communicate back to the RFmaster wiring centre. This unit has a distributionrange of approx 50m and the signal is receivedthrough an attached antenna. This antennareceives the signal from the RF room thermostatand opens or closes the thermoelectric actuatorsaccordingly.

system control 41

System Operation and Guidelines :

Once installation is complete, set the thermostatto the desired room temperature and / orsetback mode. The thermostat in any particularroom / zone must then be connected (usingcables or RF signals) to every pipe circuit in thatroom / zone, through thermoelectric actuatorssited on the return side of the underfloor heatingmanifold.

Some guidelines to the positioning of roomthermostats :

• Room thermostats be installed at a height of 1.5m in occupied spaces and at least 50cm away from any adjacent walls.

• The stat should be located in the area it controls

• The stats must not be exposed to direct solar radiator

• Avoid external walls

• Avoid recesses and alcoves

• Do not install near lamps or above radiators

• Avoid chimney walls

• Do not install directly adjacent to doors

• Do not install behind curtains

• Do not fit to walls concealing hot water pipes

Both room thermostats and actuators can bewired directly into the master (or slave) wiringcentre. The underfloor heating pump can also becontrolled by the wiring center. If any onethermostat calls for heat, it powers thesecondary underfloor heating pump as well asthe boiler and primary pump (via the relay – notsupplied). Once all the thermostats are satisfiedthe secondary underfloor heating pump shutsdown, hence shutting down the boiler andprimary pump.

The heating control panel may also be used asthe overall controller and this unit contains all thenecessary relays to energise the pumps andboiler as well as control for the underfloorheating and if desired, radiator and domestic hotwater circuits.

Suggested cable sizes to be used :

• Main UFH system pump : 3 core cable – 1.5mm / 5 amp

• Digital room thermostat : 4 core cable – 1.5mm / 5 amp

• Programmable room thermostat : 2 core – 1.5mm / 5 amp

• 4 channel time clock / programmer : 3 core – 1.5mm / 5 amp

• Fused spur to control : 4 core – 1.5mm / 5 amp

• Heating control Panel : 4 core – 1.5mm / 5 amp

Time control and temperature setback

For mixed heating systems it is advisable to usean independent time switching service fordifferent emitter circuits e.g. radiators andunderfloor heating. An underfloor heating systemwill respond relatively slowly when compared tothe traditional radiator heating system, and willtherefore benefit from an offset in timing. Theresponse of the under floor heating system isdependant on the amount of heat energy storedin the floor. To improve response times it isadvisable to setback the room temperatures byapprox 3ºC during periods where rooms areunoccupied. This can be achieved by using theset back facility on the room thermostat, with anadditional wire required for this time switchconnection. This method of control usually hasthe additional benefit of improving the energyefficiency of the heating system.

system commissioning and setup42

Pre-liminary check

• Floors should be dry before beginning commissioning.

• The building work should be complete with all external doors and windows closed. If doors and windows are open or solar gain isaffecting some rooms, the commissioning will not be accurate.

• All safety checks relating to boiler operation,system controls, wiring and water connections should have been performed before hand.

• A routine check on all aspects of the systemshould be carried out, even though some items may have been installed by others.

• It is important to know that the boiler is operating, water is flowing towards the system and that electricity is connected.

Filling

• All other heating zones (radiators / primary hot water) should be turned off and isolated.

• The isolating valves fitted on the underfloor heating zone should be turned off.

• Connect a temporary mains water supply to the supply manifold and an open hose to drain on the return manifold header.

• Ensure that all built-in valves are turned off.• Turn on the water supply and open the built

in valves to the first circuit. Allow water to flow through the circuit and out to drain.

• When you are satisfied that all the air has been purged from the circuit (the water is flowing full bore), close off the built-in valvesto that circuit.

• Repeat this operation for each circuit.• Disconnect the temporary water supply and

drain hose, open the isolating valves and allow the manifold headers to fill. Finally open all the supply manifold valves.

• Check all joints for leaks.

system commissioning and setup

Flow MetersFlow regulation and interception device with setcalibration memory and regulated flow displaysystem. Simple, direct calibration by means of anindicator which displays the circuit flow. Thespecial design also makes it possible to clean thewindow or replace the entire measurementcomponent without draining the system.

To adjust the flow meter to achievecorrect flow in each circuit :

• Adjust the flow meters as described to balance the system.

The adjustment operation is carried out in thefollowing way.

1. Turn the ring nut, A, anti-clockwise, until thelock shield is completely open.

2. Lower the ring nut, A, and calibrate using the adjuster, B, until the correct flow is reached (directly indicated by the loading capacity measure)

3. Raise the ring nut, A, until it clicks, indicating that it is in the correct (locked) position.

It is also possible to seal the ring nut into thisposition using a lead seal and the holes in thevanes (C) to fasten it:

• directly to the manifold, preventing any tampering.

• to the flow meter, making it possible to intercept the flow without changing the set calibration for maximum opening.

system commissioning and setup 43

Cleaning the window

• Turn the ring nut, A, clockwise, until the lock shield is completely closed

• Remove the window by unscrewing the adjuster, B

• Clean the window and screw it back on with the adjuster, B

• Turn the ring nut, A, anti –clockwise, until the lock shield is completely open

System setup

• The supply water temperature is correctly set on the mixing valve for the maximum required temperature.

• The system is proportionally balanced.

• Each circuit is balanced to give the design flow rate.

• The system is allowed to operate for a period in excess of 36 hours, to ensure proper circulation to all circuits.

• Check the required surface temperature is achieved in each zone. If the temperature is too low, increase the flow rate. If the temperature is too high, reduce the flow rate.

Note :Remember that heat changes slowly inunderfloor heating systems and it will take somehours before the result of any adjustments willbe noticed. Therefore, take note of eachadjustment and the effect on the system forfuture reference.When the final floor coverings are laid, thesystem flow rates may need to be re-adjusted.

System Start up

• Ensure the boiler and boiler pipe work is filled; check for and repair any leaks.

• Ensure the distribution system (underfloor loops) are correctly filled and purged of air. This is usually done one manifold at a time.It is recommended that circuits are filled and purged individually.

• System should be cleaned and flushed.• Flow meters are set as specified, settings

checked.• Set the desired supply water temperature

on the mixing valve to achieve the design supply water temperature for each zone.

• Set pressure differential bypass valve if used.

• Start and operate the boiler or heat source.• Proper and safe operation of boiler verified,

(refer to the boiler manual) venting system, controls and safety devices.

• After running the system for 24 hours verifythat there is a normal temperature difference between the system supply and return. Typical 5°C-10°C.

• With zones running under load, the boiler should cycle. If not: re-purge, check circulator operation, check control valves, and check boiler operating temperature.

guideline for homeowners44

System Water Treatment

Although Qual-PEX barrier pipe virtuallyeliminates the permeation of oxygen through thepipe wall, there are other points in the systemwhich can potentially allow oxygen into thesystem, e.g. shut-off valves, vents etc and thiscan have a detrimental effect on ferrous parts inthe system. For this reason a corrosive inhibitorshould be used and QPL recommends thefollowing :

• A silicate based corrosion inhibitor in concentration of 0.95 liter per 190 liters of water.

• A borate – nitrate corrosion inhibitor in concentration of 1400 ppm / 0.95 liter treatment per 95 liters of water.

MaintenanceAs with all types of heating systems, the movingparts associated with UFH may needmaintenance from time to time.

• The boiler should be serviced annually by an approved technician. The manifold should be checked to ensure that there are no leaks on unions or valves.

• All mixing valves, pumps (both primary andsecondary), room thermostats, thermoelectric actuators etc should be inspected visually at least once a year.

guidelines for homeowners

1. Turn the system on at the start of the heating season and allow it to operate continuously throughout.

2. On / off time switching of the system is a false economy and will lead to poor control and reduced fuel efficiency.

3. Where the controls are suitable the system may be switched to setback conditions if and when desired.

4. Room thermostats should be set to maintain the required room temperature and not used as manual switches. With underfloor heating systems it is usual to feel quite comfortable at lower room air temperatures (18oC) than normally requiredwith radiators (21oC).

5. Underfloor heating systems have a high thermal mass and therefore will respond slowly to a call for heat after a period of inactivity.

design considerations 45

• When installing any under floor heating

system, there are a number of factors

which affect its efficiency.

• In cases where the design specification is

not strictly adhered to, high fuel bills may

result leading to call-backs to a particular

job and changes to the system.

• This has also in the past lead to false

speculation that under floor heating

systems are troublesome and inefficient.

• When installed correctly, a Qual-PEX ‘Cosy

Home’ under floor heating system will work

out more efficient in terms of running cost

and will be of superior comfort over

conventional heating systems.

Ultimately this benefits everybody. It is vital that

the following points are strictly adhered to:

Primary Loop:

• The boiler schematic contained within this

specification shows the recommended

method of installing distribution pipe work

between the boiler and manifold.

• This method of installation will prevent low

temperature water being circulated through

the boiler which will significantly reduce the

efficiency of the boiler by requiring it to be

on for long periods of time to heat the

return water back up to the supply water

temperature.

design considerations

Boiler size:

• The commissioning sheet contained within

this specification details the boiler size

required for the underfloor heating only.

• The load for any additional radiators and

domestic hot water will need to be added to

this, to give the final boiler size required.

• It is vital that this boiler size is strictly

adhered to, as over sizing will lead to

wasted energy and hence increased fuel

bills.

Running times:

• Under floor heating systems operate more

efficiently on the basis of continuous

operation.

• On/Off time switching of the system will

result in fluctuating floor temperatures and

hence an additional load on the boiler.

• The setback facility of the controls supplied

should be utilised.

trouble shooting guide46

All rooms are cold :

• Check time clock

• Check thermostat setting

• Check boiler operation

• Check the supply water temperature is

correct

• Check all valves are open

• Check pump operation

Individual rooms are cold

• Check thermostat setting and location

• Check thermostat is operating the relevant

actuator head

• Check actuator is operating properly. The

actuator opens when energized.

• Check system is correctly balanced

• Check circuit valves are open

• Purge air from circuit

• Check circuits are not cross connected

All rooms are hot

• Check thermostat setting

• Check position of indictor of mixing valve

• Check pump speed. Too high or low?

• Check the supply water temperature is

correct

If the system is noisy

Check :

• That there is no air in the system

• That all pipes are firmly clipped in place and

the manifold brackets are tight

• That excessive pressure from another pump

in the system is not interfering with the

underfloor system.

trouble shooting guide

If running costs are high

Check :

• That the underfloor heating system is

correctly electrically connected to the boiler

to prevent short cycling and to ensure that

the boiler is not running when it is not

required.

• That the temperature in the rooms and the

thermostat settings are as specified.

• For any open windows. It is not unknown

for windows to be opened in cold weather

as the internal comfort remains constant

with thermostatic controls.

• That the boiler is operating correctly.

• That the floor has been properly insulated

at the construction stage.

Flow rates:

• The attached commissioning sheet (in the

design specification brief) details

the calculated flow rates for each individual

circuit. These circuits can be balanced by

setting the flow meters on the supply mani

fold to correspond to these flow rates.

• Greater flow rates than those required will

lead to an additional load on the boiler,

resulting in it being on for longer periods of

time, thereby reducing efficiency.

frequently asked questions 47

frequently asked questions

Why would I put underfloor heating in myhouse?• Comfortable even temperature throughout• Efficient on fuel due to lower operating

temperatures• Healthier environment with less dust being

circulated• Safer—no hot panels or dangerous hard

edges• No restrictions on interior design layout• Low maintenance• Maximum usable floor spaces• Excellent value for money• Independent temperature control for

all rooms.

What is the maximum area that can be covered?The is no maximum area that can be covered. The possibilities are endless.

What comes in a standard underfloor kit?The Qual-Pex Cosy Home kit comprises :• A number of coils of 15mm Qual-PEX pipe• Manifold(s) as required• Zone circulating pump(s)• Mixing valve with temperature setting• Room thermostat (s)• Thermo-electric Actuators (to control each

circuit)• A wiring centre for ease of electrical connection• Heating control panel (overall system control)• Options on various fixing systems and

insulation.

What is not included in the underfloor heating kit?Insulation, concrete screed, supply and return pipe toconnect to boiler and / or existing heating system andboiler are not included.

Can the underfloor heating be run from myboiler as a separate system ?YES. This is the best method for running theunderfloor system as it will operate as a separatezone system with direct boiler control. It can then becontrolled separately from the rest of the heatingsystems in the house.

Can the underfloor heating system be runfrom my existing radiator system ?NO. The underfloor heating is designed as a separateheating system and is best left as an independentsystem run directly for the boiler. The only exceptionto this is when a conservatory / extension UFH kit isused which allows a single room to be underfloorheated off the main radiator circuit.

What type of boiler can I use in conjunctionwith the under floor heating system?This type of heating system may be used inconjunction with any oil or gas fired boiler or even ageo-thermal heat pump system. It is notrecommended however to run the system from a solidfuel heat source.

When should I install the underfloor system?The underfloor heating can be installed during thebuild process of the dwelling on top of the sub floorand a layer of insulation.

What type of insulation is to be used ?The insulation may be either 60mm Foil-BackedPolyurethane or 100mm High Density Polystyrene.

Where do you install Edge insulation ?25mm edge insulation should be installed around allthe perimeters of each room. This is often installedby the builder.

How do I fix the underfloor pipework down ?Rapid rail and clips are used to hold the pipe in placebefore the screed is poured. Alternatively, wire meshand cable ties may be used to secure the pipe.

What pipe size shall I use ?15 mm Qual-PEX Barrier pipe is used for theunderfloor heating circuits. This pipe is supplied aspart of the kit from QPL.

What is the guarantee on the pipe ?The pipe is guaranteed for 25 years and has a lifeexpectancy of over 50 years.

Is the pipe approved ?Qual-PEX 15mm Barrier Pipe is BSI Kitemarkapproved for use under the service conditions listed inBS 7291 : Part 1 : 1990 Class S : 12 bar at 20ºC - 4bar at 82ºC - 3 bar at 92ºC with a short term overloadtemperature of 114ºC.

frequently asked questions48

What is the maximum loop length ?The maximum loop length for 15mm Qual-PEX is 100m.It is not advisable to make the loops longer than 100mbecause the pump used is only capable of pressurisingwater through 100m of pipe.

What are the lengths of the pipe loop ?The length of the circuit depends on the area covered,and is detailed in the design specification. The pipe ismarked every meter making it easy to cut to length.

How do you lay the pipe ?Always lay the pipe in order of heat output importance,for example;

1. Cold spots first. (External walls).

2. Inner walls (Internal wall).

3. Follow the standard diagram provided in the instructions

What is the distance between pipe andperimeter walls ?The pipe distance from walls should be 100 mm.

What is the minimum and maximum depth ofscreed to cover the pipe work ?The minimum depth of screed above the insulation is65mm and the maximum is 100mm

What is the drying out time for the concretescreed ?The screed drying time can be 4 to 6 weeks before theunderfloor heating system is operated. A good rule ofthumb is 1 week per 1” / 25mm of screed. The mixingvalve needs to be set at minimum temperature whencommissioning the system. Increase the temperature by2 to 3 degrees everyday. This will avoid the screedcracking.The screed must be allowed to dry out fullybefore the system is commissioned

What is the heat up time of the underfloor slab?The heat up time will take several hours from initial startup of the system to achieve satisfactory floor surface temperatures of approx 25ºC to 29ºC.

What is the cool down time of the underfloorslab ?The slab will take several hours to cool down once thesystem is fully switched off. This time may differdepending on the screed depth and the duration of thesystem running

What is the water flow temperature ?The mixing valve has a temperature setting range ofbetween 30ºC and 60ºC and should be set to ensurethat the floor surface temperature should neverexceed 29ºC.

What is the maximum temperature difference ?The system is designed to work with a temperaturedifference between the flow and the return of 7ºC -10ºC.

What are the best types of floor finishes tosuit underfloor heating ?• Tile, carpet and timber are all suitable floor

coverings. There are a few design considerations to be adhered to :

• Tile : Use special adhesive suitable for undefloorheating

• Timber : Use timber that has been kiln dried to approx 8%.

• Carpet : Always use a good quality thin carpet and a good quality underlay.

• Always consult your flooring provider before youlay a finished floor on top. They will provide you with the best advice on choosing a floor covering most suitable for underfloor heating

Is it More Expensive Than Radiators toInstall? The initial investment is higher than a radiator system but the end result is lower running costs, abetter form of comfort and a hidden heating system

Is it a complicated system to install?All QPL underfloor heating systems are relativelyeasy to install. Simply follow our AutoCAD designdrawing for the pipe patterns and loop lengths. A fulldesign specification goes out with each projectdetailing zone layouts, commissioning details, systemsetup and operation and of course all mechanical andelectrical diagrams and data sheets.

Are we confined to just underfloor heating?Not at all. You can incorporate underfloor heating witha radiator system and domestic hot water can also beaccommodated from the primary circuit. This allowsyou to have individual control over the three systems.

Will I have control over each zone?Yes. Individual room thermostats are supplied foreach room or zone allowing you to have acompletely independent zone-by-zone system.

notes 49

notes50

QPL Ireland P.O. Box 29 • White’s Cross • Cork • IrelandTel: +353-21-488 4700 •Fax: +353-21-488 4706Email: qpl@qpl.ie Web: www.qpl.ie

Pipelife UK Depot 13 Saxon Way East • Oakley Hay Industrial Estate •Corby • Northants • NN18 9EY.Tel: 0845 2419 490 • Fax: 0845 2419 491Email: info@pipelife.co.uk • Web: www.pipelife.co.uk