Potterton Promax SL series Installation and maintenance instructions

CompNo5121908Iss164/13
Youcanrelyon
Installation&ServiceInstructions
PromaxSLRange
CondensingCentralHeatingBoiler
TheseinstructionsincludetheBenchmarkCommissioningChecklistandshouldbeleftwiththeuserforsafekeeping.
©BaxiHeatingUKLtd2013
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NaturalGas
PottertonPromax12SL
G.C.No4159179
PottertonPromax15SL
G.C.No4159187
PottertonPromax18SL
G.C.No4159180
PottertonPromax24SL
G.C.No4159188
PottertonPromax30SL
G.C.No4159189
TheBenchmarkScheme
Benchmarkplacesresponsibilitiesonbothmanufacturersandinstallers.Thepurposeistoensurethatcustomersareprovidedwiththe
correctequipmentfortheirneeds,thatitisinstalled,commissionedandservicedinaccordancewiththemanufacturer'sinstructionsby

competentpersonsandthatitmeetstherequirementsoftheappropriateBuildingRegulations.TheBenchmarkChecklistcanbeusedto
demonstratecompliancewithBuildingRegulationsandshouldbeprovidedtothecustomerforfuturereference.
Installersarerequiredtocarryoutinstallation,commissioningandservicingworkinaccordancewiththeBenchmarkCodeofPractice
whichisavailablefromtheHeatingandHotwaterIndustryCouncilwhomanageandpromotetheScheme.Visit
www.centralheating.co.ukformoreinformation.
©BaxiHeatingUKLtd2013Allrightsreserved.Nopartofthispublicationmaybereproducedortransmittedinanyformorbyany
means,orstoredinanyretrievalsystemofanynature(includinginanydatabase),ineachcasewhetherelectronic,mechanical,
recordingorotherwise,withoutthepriorwrittenpermissionofthecopyrightowner,exceptforpermittedfairdealingunderCopyrights,
DesignsandPatentsAct1988.
Applicationsforthecopyrightowner'spermissiontoreproduceormakeotheruseofanypartofthispublicationshouldbemade,giving
detailsoftheproposeduse,tothefollowingaddress:
TheCompanySecretary,
BaxiHeatingUKLimited,
BrooksHouse,
CoventryRoad,
Warwick.
CV344LL
Fullacknowledgementofauthorandsourcemustbegiven.
WARNING:Anypersonwhodoesanyunauthorisedactinrelationtoacopyrightworkmaybeliabletocriminalprosecutionandcivil
claimsfordamages.
BuildingRegulationsandtheBenchmarkCommissioningChecklist
BuildingRegulations(England&Wales)requirenotificationoftheinstallationofaheatingappliancetotherelevantLocalAuthority
BuildingControlDepartment.From1April2005thiscanbeachievedviaaCompetentPersonsSelfCertificationSchemeasanoptionto
notifyingtheLocalAuthoritydirectly.SimilararrangementswillfollowforScotlandandwillapplyinNorthernIrelandfrom1January2006.
TheHealth&SafetyExecutiveoperatesthe‘GasSafeRegister’,aselfcertificationschemeforgasheatingappliances.
ThesearrangementsrepresentachangefromthesituationwherebycompliancewithBuildingRegulationswasacceptedasbeing
demonstratedbycompletionoftheBenchmarkLogbook(whichwasthenleftonsitewiththecustomer).
WiththeintroductionofSelfCertificationSchemes,theBenchmarkLogbookisbeingwithdrawn.However,asimilardocumentinthe
formofacommissioningchecklistandserviceintervalrecordisincorporatedatthebackoftheseinstructions.
ThiscompanyisamemberoftheBenchmarkinitiativeandfullysupportstheaimsoftheprogramme.Itsaimistoimprovethe
standardsofinstallationandcommissioningofcentralheatingsystemsintheUKandtoencouragetheregularservicingofallcentral
heatingsystemstoensuresafetyandefficiency.
BuildingRegulationsrequirethatinstallationsshouldcomplywithmanufacturer'sinstructions.Itisthereforeimportantthatthe
commissioningchecklistiscompletedbytheinstaller.TherelevantsectionofBuildingRegulationsonlyrelatestodwellings.Therefore
thechecklistonlyappliesiftheapplianceisbeinginstalledinadwellingorsomerelatedstructure.
TheflowchartbelowgivesguidanceforinstallersontheprocessnecessarytoensurecompliancewithBuildingRegulations.
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InstallerNotificationGuidelines

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Legislation

IMPORTANTInstallation,Commissioning,Service&Repair
Thisappliancemustbeinstalledinaccordancewiththemanufacturer'sinstructionsandtheregulationsinforce.Readtheinstructions
fullybeforeinstallingorusingtheappliance.
InGB,thismustbecarriedoutbyacompetentpersonasstatedintheGasSafety(Installation&Use)Regulations.
Definitionofcompetence:ApersonwhoworksforaGasSaferegisteredcompanyandholdingcurrentcertificatesintherelevantACS
modules,isdeemedcompetent.
InIE,thismustbecarriedoutbyacompetentpersonasstatedinI.S.813"DomesticGasInstallations".
NOTE:Theadditionofanythingthatmayinterferewiththenormaloperationoftheappliancewithoutexpresswrittenpermissionfromthe
manufacturerorhisagentcouldinvalidatetheappliancewarranty.InGBthiscouldalsoinfringetheGasSafety(InstallationandUse)
Regulations.
WarningChecktheinformationonthedataplateiscompatiblewithlocalsupplyconditions.
AllGasSaferegisteredengineerscarryanIDcardwiththeirlicencenumberandaphotograph.Youcancheckyourengineeris
registeredbytelephoning08004085500oronlineatwww.gassaferegister.co.uk
TheboilermeetstherequirementsofStatutoryInstrument"TheBoiler(Efficiency)Regulations1993No3083"andisdeemedtomeet
therequirementsofDirective92/42/EEContheenergyefficiencyrequirementsfornewhotwaterboilersfiredwithliquidorgaseous
fuels:
TypetestforpurposeofRegulation5certifiedby:
NotifiedBody0087.

Product/Productioncertifiedby:
NotifiedBody0086.
ForGB/IEonly.

Thiscompanydeclaresthatnosubstancesharmfultohealtharecontainedintheapplianceorusedduringappliance
manufacture.
TheapplianceissuitableonlyforinstallationinGBandIEandshouldbeinstalledinaccordancewiththerulesinforce,and
onlyusedinasuitablyventilatedlocation.
InGB,theinstallationmustbecarriedoutbyaGasSafeRegisteredInstaller.Itmustbecarriedoutinaccordancewiththerelevant
requirementsofthe:
GasSafety(Installation&Use)Regulations.
TheappropriateBuildingRegulationseitherTheBuildingRegulations,TheBuildingRegulations(Scotland),BuildingRegulations
(NorthernIreland).
TheWaterFittingsRegulationsorWaterByelawsinScotland.
TheCurrentI.E.E.WiringRegulations.
Wherenospecificinstructionsaregiven,referenceshouldbemadetotherelevantBritishStandardCodeofPractice.
InIE,theinstallationmustbecarriedoutbyacompetentPersonandinstalledinaccordancewiththecurrenteditionofI.S.813
'DomesticGasInstallations',thecurrentBuildingRegulationsandreferenceshouldbemadetothecurrentETCIrulesforelectrical
installation.
Allsystemsmustbethoroughlyflushedandtreatedwithinhibitor(seesection6.2).
CodesofPractice,mostrecentversionshouldbeused
InGBthefollowingCodesofPracticeapply:
Standard Scope
BS6891 GasInstallation.
BS5546 Installationofhotwatersuppliesfordomesticpurposes.
BSEN12828 Heatingsystemsinbuildings.
BSEN12831 Heatingsystemsinbuildingscalculationsofload
BSEN14336 Installation&commissioningofwaterbasedheatingsystems.
BS6798 Installationofgasfiredhotwaterboilers.
BS5440Part1 Flues.
BS5440Part2 Ventilation.
BS7074 Expansionvesselsandancillaryequipmentforsealedwatersystems.
BS7593 Treatmentofwaterindomestichotwatercentralheatingsystems.
InIEthefollowingCodesofPracticeapply:

Standard Scope
I.S.813 DomesticGasInstallations.
ThefollowingBSstandardsgivevaluableadditionalinformation;
BS5546 Installationofhotwatersuppliesfordomesticpurposes.
BSEN12828 Heatingsystemsinbuildings.
BSEN12831 Heatingsystemsinbuildingscalculationsofload
BSEN14336 Installation&commissioningofwaterbasedheatingsystems.
BS7074 Expansionvesselsandancillaryequipmentforsealedwatersystems.
BS7593 Treatmentofwaterindomestichotwatercentralheatingsystems.
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SafeManualHandling
General
Thefollowingadviceshouldbeadheredto,fromwhenfirsthandlingtheboilertothefinalstagesofinstallation,andalsoduring
maintenance.
Mostinjuriesasaresultofinappropriatehandlingandliftingaretotheback,butallotherpartsofthebodyarevulnerable,particularly
shoulders,armsandhands.Health&SafetyistheresponsibilityofEVERYONE.
Thereisno'safe'limitforonemaneachpersonhasdifferentcapabilities.TheboilershouldbehandledandliftedbyTWOPEOPLE.
Donothandleorliftunlessyoufeelphysicallyable.
WearappropriatePersonalProtectionEquipmente.g.protectivegloves,safetyfootwearetc.
Preparation
Coordinatemovementsknowwhere,andwhen,youarebothgoing.
Minimisethenumberoftimesneededtomovetheboilerplanahead.
Alwaysensurewhenhandlingorliftingtherouteisclearandunobstructed.Ifpossibleavoidsteps,wetorslipperysurfaces,unlitareas
etc.andtakespecialcareonladders/intolofts.
Technique
Whenhandlingorliftingalwaysusesafetechniqueskeepyourbackstraight,bendyourknees.Don'ttwistmoveyourfeet,avoid
bendingforwardsandsidewaysandkeeptheloadasclosetoyourbodyaspossible.
Wherepossibletransporttheboilerusingasacktruckorothersuitabletrolley.
Alwaysgriptheboilerfirmly,andbeforeliftingfeelwheretheweightisconcentratedtoestablishthecentreofgravity,repositioning
yourselfasnecessary.Seesection8.3oftheseinstructionsforrecommendedliftpoints.
Remember
Thecircumstancesofeachinstallationaredifferent.Alwaysassestherisksassociatedwithhandlingandliftingaccordingtothe
individualconditions.
IfatanytimewheninstallingtheboileryoufeelthatyoumayhaveinjuredyourselfSTOP!!DONOT'workthrough'thepainyoumay
causefurtherinjury.
IFINANYDOUBTDONOTHANDLEORLIFTTHEBOILEROBTAINADVICEORASSISTANCEBEFOREPROCEEDING!!
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Contents
1.0Introduction
2.0GeneralLayout
3.0ApplianceOperation
4.0TechnicalData
5.0DimensionsandFixings
6.0SystemDetails
7.0SiteRequirements
8.0FlueOptions
9.0PlumeDisplacement

10.0Installation
11.0Electrical
12.0CommissioningtheBoiler
13.0FittingtheOuterCase
14.0ServicingtheBoiler
15.0ChangingComponents
16.0ShortPartsList
17.0FaultFinding
BenchmarkChecklist
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1.0Introduction
1.1Description
1.ThePottertonPromaxSLrangearegasfiredroomsealedfanassistedcondensingcentralheatingboilers.
2.ThemaximumoutputofthePottertonPromax12SLis40,330Btu/hr,15SLmodelis52,000Btu/hr,18SLmodelis60,770Btu/hr
and24SLmodelis75,000Btu/hr.Themaximumoutputofthe30SLmodelispresetat75,000Btu/hrbutcanbesetto100,000
Btu/hr(seesection10.8).Allboilersautomaticallyadjusttheiroutputsaccordingtothesystemload.
3.ItisdesignedforuseonNaturalGas(G20).
4.Theboilerissuitableforfullypumpedopenventedcentralheatinganddomestichotwatersystemsandsealedsystems.
5.Alabelgivingdetailsofthemodel,serialnumberandGasCouncilnumberissituatedontherearofthelowerdoorpanel(Fig.1).

Fig.1
6.Theboilerdatabadgeispositionedontheairboxdoor(Fig.2).


Fig.2
7.Theboilerisintendedtobeinstalledinresidential/commercial/lightindustrialE.M.C.environmentsonagovernedmetersupply
only.
8.Theboilermustbeinstalledwithoneofthepurposedesignedfluessuchasthestandardhorizontalfluekit,partno236921.
1.2ImportantInformation
Manmademineralfibre
Somecomponentpartsofthisappliance(insulationpads,gasketsandropeseals)aremanufacturedfrommanmademineral
fibre.
Prolongedorexcessiveexposuretothismaterialmayresultinsomeirritationtotheeyes,skinorrespiratorytract.
Itisadvisabletoweargloveswhenhandlingtheseitems.
Irritantdustwillonlybereleasedfromtheitemsiftheyarebrokenuporsubjectedtosevereabrasion.Intheseinstancesa
suitabledustmaskandgogglesshouldbeworn.
Alwaysthoroughlywashhandsafterinstallation,servicingorchangingcomponents.
Whendisposingofanyitemsmanufacturedfrommanmademineralfibrecaremustbeexercised.
Ifanyirritationoftheeyesorsevereirritationoftheskinisexperiencedseekmedicalattention.
1.3ContentsofPack
Thepackcontains:
Boiler
WallPlate
Template&'QuickFit'Guide
LiteraturePack
FittingsPack
page7
2.0GeneralLayout
2.1Layout(Figs.3,4,5&6)


1. WallPlate
2. FlueElbow
3. HeatExchanger
4. Burner

5. AirBox
6. FanProtectionThermostat
7. FanAssembly
8. CondensateTrap
9. PCBHousingAssembly
10. GasTap
11. Gas/AirRatioValve
12. FlowPipeConnection
13. ReturnPipeConnection
14. FlowTemperatureSafetyThermostatBlack
15. FlowTemperatureThermistorRed
16. FlowSwitch(dryfireprotection)
page8
3.0ApplianceOperation
3.1
1.SwitchedLiveOn:Whentheswitchedliveswitchesoniftheflowtemperatureislessthanthesetpointthenpumpoverrun
occurs.Whentheswitchedliveswitchesoniftheflowtemperatureisgreaterthanthesetpointthenpumpoverrunoccurs.
2.PumpOn:Thepumpisonwhilethefan,sparkgeneratorandgasvalveareoff.After10secondsiftheflowswitchhasmade
thenfanprepurgeoccurs.After10secondsiftheflowswitchhasnotmadethenanticycleoccurs.
3.FanPrePurge:Thepumpandfanareonwhilethesparkgeneratorandgasvalveareoff.After5secondsignitionoccurs.
4.Ignition:Thepump,fan,sparkgeneratorandgasvalveareon.Ifaflameisdetectedthenburneronoccurs.Ifaflameisnot
detectedwithin5secondsandlessthan5ignitionattemptshavebeenmadethenfanpurgeoccurs.Ifaflameisnotdetected
within5secondsand5ignitionattemptshavebeenmadethenignitionlockoutoccurs.
5.BurnerOn:Thepump,fanandgasvalveareonwhilethesparkgeneratorisoff.Flowtemperatureiscontrolledbyvaryingthe
fanspeed(andtherebythegasrate)toachieveoptimumoperation.Iftheflowtemperatureisgreaterthanthesetpointorthe
TRVsallshutdownthenfanpostpurgeoccurs.
6.FanPostPurge:Thepumpandfanareonwhilethesparkgeneratorandgasvalveareoff.After5secondsiftheTRVsarenot
shutdownthenpumpoverrunoccurs.After5secondsiftheTRVsareshutdownthenanticycleoccurs.
7.PumpOverrun:Thepumpisonwhilethefan,sparkgeneratorandgasvalveareoff.After1minuteanticycleoccurs.
8.Anticycle:Thepump,fan,sparkgeneratorandgasvalveareoff.After3minutesiftheflowtemperatureislessthantheset
pointthenpumponoccurs.After3minutesiftheflowtemperatureisgreaterthanthesetpointthenpumpoverrunoccurs.
9.IgnitionLockout:Thepump,fan,sparkgeneratorandgasvalveareoff.Theboilercanonlyberesetbymanuallyusingthereset
button.

page9
4.0TechnicalData
ApplianceType C13 C33 C53
ApplianceCategory CATI2H
HeatInput(Q) (Gross) Max Min
12model kW 13.34 10.2
 Btu/hr 45,518 34,840
15model kW 16.88 10.2
 Btu/hr 57,600 34,840
18model kW 20.18 10.2
 Btu/hr 68,850 34,840
24model kW 24.50 10.2
 Btu/hr 83,600 34,840
30model kW 33.76 10.2
(seenote) Btu/hr 115,200 34,840
HeatOutput(P)

(NonCondensing70°CMeanWaterTemp)
  Max Min
12model kW 11.82 9.14
 Btu/hr 40,330 31,180
15model kW 15.24 9.14
 Btu/hr 52,000 31,180
18model kW 17.81 9.14
 Btu/hr 60,770 31,180
24model kW 22.00 9.14
 Btu/hr 75,000 31,180
30model kW 30.18 9.14
 Btu/hr 102,980 31,180
HeatOutput(P)
(Condensing40°CMeanWaterTemp)
  Max Min
12model kW 12.81 
 Btu/hr 43,400 
15model kW 16.49 10.1
 Btu/hr 56,260 34,520
18model kW 19.27 
 Btu/hr 64,898 
24model kW 23.8 10.1
 Btu/hr 81,200 34,520
30model kW 32.61 10.1
 Btu/hr 113,280 34,520
MaxGas
Rate (2HG2020mbar)
(After10
Mins)     
 (12) (15) (18) (24) (30)
Btu/hr 40,950 52,000 61,400 75,000 102,980
m3/hr 1.34 1.64 1.94 2.31 2.95
ft3/hr 47.3 52.1 68.5 83.3 104.2
Injector(NaturalGas)
 6.5mmDiameter
NoxClass 5 
Horizontal
FlueTerminal Diameter 110mm
Dimensions Projection 150mm
Connections
GasSupply  ½inBSPT
CentralHeatingFlow  22mm
CentralHeatingReturn  22mm
CondensateDrain  1inBSP
OutercaseDimensions
OverallHeightIncFlueElbow  750mm
CasingHeight  600mm
CasingWidth  390mm
CasingDepth  280mm
Clearances
(ForunventilatedcompartmentsseeSection7.2)
BothSides 5mmMin
AboveCasing 200mmMin
BelowCasing 50mmMin
Front(ForServicing) 500mmMin
Front(InOperation) 5mmMin

Weights kg
PackagedBoilerCarton 36.2
PackagedFlueKit 3.6
InstallationLiftWeight 26.0
CO/CO2Ratio Uptoamaximumof0.004
CO2Level 9%±1%

ElectricalSupply 230V~50Hz
(Appliancemustbeconnectedtoanearthedsupply)
PowerConsumption 80W
ExternalFuseRating 3A
InternalFuseRating(BS4265)
 Fuse 3.15AT(PCB)
ElectricalProtection IPX2
WaterContent
 litres 2.6
 pints 4.6
StaticHead
 max 30metres(100ft)
 min 1metre(3.25ft)
LowHead 0.2m(8in)min
SystemDetail
fullypumpedopenvented&sealedsystems
GasConnection
 G½"B.S.P.Thread
Controls
boilerthermostat,safetythermostat,flowswitch,electronicflame
sensing,temperatureprotectionthermostat&condensateblockage
sensor
InletPressureatGasValve(NaturalGas)
 Min 18.1mbar
 Max 22.5mbar
 (seeSection12.1)
FlowTemperature(adjustable)
 55°Cto78°C(±5°C)
RecommendedSystem
TemperatureDrop
 Condensing 20°C 36°F
NOTE:Alldatainthissectionarenominalvaluesandsubjecttonormalproductiontolerances

NOTE:Themaximumoutputofthe30modelisfactorysetat22.0kW(75,000Btu/hr).
Thiscanbealteredto30.18kW(102,980Btu/hr)seesection10.8.

SEDBUKDeclaration
For12modelTheefficiencyis90.5%
For15modelTheefficiencyis91.3%
For18modelTheefficiencyis90.4%
For24modelTheefficiencyis90.9%
For30modelTheefficiencyis90.9%
ThisvalueisusedintheUKGovernment'sStandard
AssessmentProcedure(SAP)forenergyratingofdwellings.
Thetestdatafromwhichithasbeencalculatedhasbeencertifiedby0087.

page10
5.0DimensionsandFixings

DIMENSIONS
A
600mm
B
280mm
C
390mm
D

150mmØ
Min.
E
162.5mm
F 96mm
The1.5°fallprovidedbytheelbowistoallowcondensatetorunbacktotheboiler,fordisposalthroughthecondensatedischargepipe.
Fig.7
SIDEFLUE(leftandright)
Forevery1mofhorizontalfluelength,theclearanceabovethetopoftheflueelbow
shouldbe27.5mmtoincorporatethe1.5°fallinthefluefromtheterminaltotheelbow.
Fluelength(Y) Clearance(X)
upto1m 27.5mm
1m2m 55mm
2m3m 82.5mm
Fig.8
page11
6.0SystemDetails
6.1WaterCirculatingSystems
1.Theapplianceissuitableforusewithopenventfullypumpedsystemsandsealedsystems.
Thefollowingconditionsshouldbeobservedonallsystems:
Thestaticheadmustnotexceed30m(100ft)ofwater.
Theboilermustnotbeusedwithadirectcylinder.
Draincocksshouldbefittedtoallsystemlowpoints.
Allgasandwaterpipesandelectricalwiringmustbeinstalledinawaywhichwouldnotrestricttheservicingoftheboiler.
Positionisolatingvalvesasclosetocirculatingpumpaspossible.
Itisrecommendedthatthereturnpipeisfittedwithanautomaticairventasclosetotheboilerasispractical.
6.2TreatmentofWaterCirculatingSystems
Allrecirculatorywatersystemswillbesubjecttocorrosionunlessanappropriatewatertreatmentisapplied.Thismeansthatthe
efficiencyofthesystemwilldeteriorateascorrosionsludgeaccumulateswithinthesystem,riskingdamagetopumpandvalves,
boilernoiseandcirculationproblems.
Whenfittingnewsystemsfluxwillbeevidentwithinthesystem,whichcanleadtodamageofsystemcomponents.

Allsystemsmustbethoroughlydrainedandflushedoutusing,forexample,SentinelX300orX400orFernoxF3.Theyshouldbe
usedfollowingtheflushingagentmanufacturer'sinstructions.
Systemadditivescorrosioninhibitorsandflushingagents/descalersshouldcomplytoBS7593requirements,e.g.SentinelX100
andFernoxMB1whichshouldbeusedfollowingtheinhibitormanufacturer'sinstructions.
Fullinstructionsaresuppliedwiththeproducts,forfurtherinformationcontactSentinel(08003894670)orFernox(08708700362)
Failuretoflushandaddinhibitortothesystemwillinvalidatetheappliancewarranty.
Itisimportanttochecktheinhibitorconcentrationafterinstallation,systemmodificationandateveryserviceinaccordancewith
themanufacturer'sinstructions.(Testkitsareavailablefrominhibitorstockists.)
ForinformationoradviceregardinganyoftheabovecontactTechnicalEnquiries.
page12
6.3Pipework
1.Thesizesofflowandreturnpipesfromtheboilershouldbedeterminedbynormalmethods,accordingtotherequirementsofthe
system.Theconnectionsontheboilerare22mm.
2.A20°C(36°F)dropintemperatureacrossthesystemisrecommendedforcondensingboilers.Existingradiatorsmaybe
oversizedandsoallowthis,butwhereradiatorsizingismarginalitmaybeadvisabletoretainasystemtemperaturedropof11°C
(20°F).
NOTE:On30models28mmpipeshouldbeusedtoconnect
totheboilerflowandreturn.
3.InsystemsusingnonmetallicpipeworkitisnecessarytousecopperpipefortheboilerFlowandReturn.Thecoppermustextend
atleast1metrefromtheboilerandincludeanybranches(Fig.9).

Fig.9
6.4LowHeadInstallation
1.Usingaclosecouplearrangementtheminimumheadisasshowninthediagrams(Figs.10&11)subjecttothefollowing
conditions:
a)Thepumpbeingadjustedtogivea20°Cdropacrosstheboiler.
b)Thepumpmustbefittedontheflow.
c)Thepumpmustbefittedinaccordancewiththepumpmanufacturer'sinstructions.
d)Theopenventpipemustbetakenupfromateeinahorizontalsectionoftheflowpipe.
AnalternativeLowHeadInstallation(Fig.12)


TypicalLowHeadInstallation
Fig.10

Fig.11
IfConditionsRequire,ThisSystemPossible
AlternativeLowHeadInstallation
Fig.12
2.Forheadsbelow400mmthenacombinedventandfeedpipemaybeconnected.Thismustbeaminimumof22mmdiameter.It
isrecommendedthatanairseparatorisfittedwhenusingacombinedfeedandventpipe.
6.5Pump
1.Providingthatthecoldfeedandopenventpipearepositionedcorrectly(e.g.thesystemisnotpronetopumpingover,air
entrainmentetc.)thepumpmaybefittedontheprimaryreturnpipe.

page13
Keytocolours
b Blue
br  Brown
w White
o Orange
gr  Grey
g/y  Green/Yellow
YPlan,RoomThermostatSystem,CHInterlockedByRoomThermostat
AtleasttheRadiator(s)neartheRoomThermostatnotTRV'd
PumprunfromSwitchedLive
BypasspermittedbutnotrequiredforPartL1compliance
SPlan,RoomThermostatSystem,CHInterlockedByRoomThermostat
AtleasttheRadiator(s)neartheRoomThermostatnotTRV'd
PumprunfromSwitchedLive
BypasspermittedbutnotrequiredforPartL1compliance

YPlan,FullyTRV'dSystem,CHInterlockedByBoilerFlowSwitch
RoomThermostatshouldnotbefitted
PumpmustberunfromBoilerP/FconnectionforPartL1compliance
Bypassnotpermitted(mustbevalvedoff)forPartL1compliance
SPlan,FullyTRV'dSystem,CHInterlockedByBoilerFlowSwitch
RoomThermostatshouldnotbefitted
PumpmustberunfromBoilerP/FconnectionforPartL1compliance
Bypassnotpermitted(mustbevalvedoff)forPartL1compliance
6.6SystemControls
Thisboilerdoesnotrequireabypass.
Thisboilerdoesnotrequireapermanentlive.
ThepumponlyneedswiringdirectlytotheboilerforfullyTRV'dsystems.
1.TocomplywithPartL1oftheBuildingRegulationstheheatingsystemintowhichtheboilerisinstalledshouldincludethe
following:
a)zonecontrols
b)timingcontrols
c)boilercontrolinterlocks
2.Suchasystemneedstobefullypumpedandmustprovideindependenttemperatureandtimecontroltoboththeheatingandhot
watercircuitsandhaveaboilerinterlock.

3.Theboilershouldbecontrolledsothatitoperatesondemandonly.Whereitisproposedtoeffectcontrolbythermostaticradiator
valves,aroomthermostat(orotherdevicesuchasaflowswitchaflowswitchisintegraltothisboiler)shouldalsobeprovided
toswitchofftheboilerwhenthereisnodemandforheatingorhotwater.
4.TheinterlockfortheCHcircuitcanbeprovidedbyeitheraRoomThermostatorafullyTRV'dsystemwiththepumpwiredbackto
theboilerwithoutabypass.ConnectiondiagramsforbothoptionsforYandSplansystemsareshown.
page14
6.7SealedSystems(Fig.13)

MaxBoilerFlowTemp=82°C
Fig.13
1.SAFETYVALVEAsafetyvalvecomplyingwiththerequirementsofBS6750Part1mustbefittedclosetotheboilerontheflow
pipebymeansofahorizontalorverticallyupwardconnectionwithnointerveningvalveorrestrictionsandshouldbepositionedto
facilitatetesting.Thevalveshouldbepresetandnonadjustabletooperateatapressureof3bar(45Ibf/in2).Itmustbearranged
todischargeanywaterorsteamthroughapipetoasafeoutletposition.
2.PRESSUREGAUGEApressuregaugeofminimumrange04bar(060Ibf/in2)withafillpressureindicatormustbefittedtothe
system,preferablyatthesamepointastheexpansionvesselinaneasilyvisibleposition.
3.EXPANSIONVESSELAnexpansionvesselcomplyingwiththerequirementsofBS4814mustbefittedtothesystemby
meansofaconnectionclosetotheinletsideofthecirculatingpumpinaccordancewiththemanufacturersinstructions,the
connectingpipebeingunrestrictedandnotlessthan15mm(½in)nominalsize.Thevolumeofthevesselshouldbesuitablefor
thesystemwatercontentandthenitrogenorairchargepressureshouldnotbelessthanthesystemstatichead(SeeTable.1).

MethodofdeterminingminimumvalveofexpansionvesselvolumeforsealedsystemsusingPottertonBoilers
VesselCharge
Pressure(Bar)
InitialSystem
Pressure(Bar)
MultiplyTotal
WaterContentOf
SystemBy(Litres)
0.5
0.5
1.0
1.5
2.0
0.067
0.112
0.207
0.441
1.0
1.0
1.5
2.0
0.087
0.152
0.330
1.5 1.5
2.0
0.125
0.265
Example: SystemVolume=75litres
VesselChargePressure=1.0bar
InitialSystemPressure=1.5bar
Then: 75x0.152=11.4litres
ExpansionVesselVolume
NOTE
Whereavesselofthecalculatedsizeisnotobtainablethenthenextavailablelargersizeshouldbeused.
Table.1

FurtherdetailsofsealedsystemdesigncanbeobtainedfromBS5449andtheBritishGaspublicationentitled'Specificationsfor
DomesticWetCentralHeatingSystems'.
4.FILLINGPOINTAfillingpointconnectiononthecentralheatingreturnpipeworkmustbeprovidedtofacilitateinitialfillingand
pressurisingandalsoanysubsequentwaterlossreplacement/refilling.Thesealedprimarycircuitsmaybefilledorreplenished
bymeansofatemporaryconnectionbetweentheprimarycircuitandasupplypipeprovideda'Listed'doublecheckvalveorsome
othernolesseffectivebackflowpreventiondeviceispermanentlyconnectedattheinlettothecircuitandthetemporary
connectionisremovedafteruse.Thefillingmethodadoptedmustbeinaccordancewithallrelevantwatersupplyregulationsand
useapprovedequipment.
Yourattentionisdrawnto,forGB:GuidanceG24.2andrecommendationR24.2oftheWaterRegulationsGuide.forIE:thecurrent
editionofI.S.813"DomesticGasInstallations".
5.MAKEUPSYSTEMAmethodofreplacingwaterlostfromthesystemshouldbeprovidedeitherbymeansofamakeupvessel
ofnotmorethan3litres(5pints)capacity,mountedabovethehighestpointofthesystem,orbyrepressurisationofthesystem.
6.VENTINGAmethodofventingthesystemduringfillingandcommissioningmustbeprovidedbyfittingautomaticairventsorby
ventingmanually.
7.HOTWATERSTORAGEThehotwaterstoragevesselmustbeoftheindirectcoiltype.Allcomponentsusedinthesystem
mustbesuitableforoperationat110°C(230°F)andatthepressureallowedbythesafetyvalve.
Fig.14
page15
7.0SiteRequirements
7.1Location
NOTE:Duetothehighefficiencyoftheboileraplumeofwatervapourwillbedischargedfromtheflue.
Thisshouldbetakenintoaccountwhensitingtheflueterminal.
1.Theboilermaybefittedtoanysuitablewallwiththefluepassingthroughanoutsidewallorroofanddischargingtoatmospherein
apositionpermittingsatisfactoryremovalofcombustionproductsandprovidinganadequateairsupply.Theboilershouldbe
fittedwithinthebuildingunlessotherwiseprotectedbyasuitableenclosurei.e.garageorouthouse.(Theboilermaybefitted
insideacupboardseeSection7.2).
2.Iftheboilerissitedinanunheatedenclosurethenitisrecommendedtoincorporateanappropriatedeviceforfrostprotectionin
thesystemcontrols.
3.IftheboilerisfittedinaroomcontainingabathorshoweritMUSTNOTBEfittedinzone0,1or2,ONLYwithintheshadedarea
(Figs.A&Bshowszonedimensionsforabathtub.ForotherexamplesrefertotheCurrentI.E.E.WiringRegulations)reference
mustbemadetotherelevantrequirements.InGBthisisthecurrentI.E.E.WiringRegulationsandBuildingRegulations.InIE
referenceshouldbemadetothecurrenteditionofI.S.813"DomesticGasInstallations"andthecurrentETCIrules.
