Fig.13b
page19
7.8CondensateDrain
FAILURETOINSTALLTHECONDENSATEDISCHARGEPIPEWORKCORRECTLY
WILLAFFECTTHERELIABLEOPERATIONOFTHEBOILER.
CAREFULCONSIDERATIONMUSTBEGIVENTOTHEPOSSIBILITYOFTHEPIPEWORKBEING
SUBJECTTOFREEZINGCONDITIONSANDAPPROPRIATEMEASURESTAKENTOPREVENTBLOCKAGE.
CORRECTINSTALLATIONINACCORDANCEWITHTHISSECTIONWILLCONSIDERABLYMINIMISE
THELIKELIHOODOFBLOCKAGEANDSUBSEQUENTBOILERLOCKOUT.
ACONDENSATEDISCHARGEPUMPANDPIPE'TRACEHEATING'AREAVAILABLEASACCESSORIES
seeparagraph7.8.12to7.8.15forfurtherdetails.
ThecondensatedischargepipeMUSTNOTRISEatanypointalongitslength.
ThereMUSTbeafallofATLEAST2.5°(50mmpermetre)alongtheentirerunEXCEPTwhenemployinga
suitablecondensatepumpinbasementandcellarorsimilarapplications.
Theboilercondensatetrapincorporatesasealof75mm,thereforeitisunnecessarytoinstallanairbreak
andtrapinthedischargepipework.
1.Thecondensateoutletwillaccept21.5mm(3/4in)plasticoverflowpipe.Itisstronglyrecommendedthatthisdischargesinternallyintothehouseholddrainage
system.Wherethisisnotpossible,dischargeintoanoutsidedrainispermissibleprovidingeverypossibleprecautionistakentopreventfreezing.
2.Ensurethedischargeofcondensatecomplieswithanynationalorlocalregulationsinforce.BS6798&PartH1oftheBuildingRegulationsgivefurtherdetailed
guidance.
3.Thedischargepipeshouldberuninaproprietarydrainpipemateriale.g.PVC,PVCU,ABS,PVCCorPP.
4.MetalpipeworkisNOTsuitableforuseincondensatedischargesystems.
5.Thepipeshouldbeaminimumof21.5mmdiameterandmustbesupportedusingsuitablyspacedclipsofthecorrectdesigntopreventsagging.
6.Itisadvisablethatthefulllengthofcondensatepipeisruninternallyandpreferablybelessthan3metres.
7.Internalrunsgreaterthan3metresorrunsincoldareasshoulduse32mmwastepipe.
8.ExternalrunsMUSTbeaMINIMUMof32mmandfullyinsulatedwithmaterialsuitableforexternaluse.
9.Iftheboilerisfittedinanunheatedlocationtheentirecondensatedischargepipeshouldbetreatedasanexternalrunandsizedandinsulatedaccordingly.
10.Inallcasesdischargepipemustbeinstalledtoaiddisposalofthecondensate.Toreducetheriskofcondensatebeingtrapped,asfewbendsandfittingsaspossible
shouldbeusedandanyburrsoncutpiperemoved.
Examplesareshownofthefollowingmethodsoftermination:
i)toaninternalsoil&ventpipe
ii)viaaninternaldischargebranch(e.g.sinkwaste)downstreamofthetrap
iii)toadrainorgully
iv)toapurposemadesoakaway
v)pumpedintoaninternaldischargebranch(e.g.sinkwaste)downstreamofthetrap
vi)pumpedintoanexternalsoil&ventpipe
vii)toadrainorgullywithextendedexternalrun&traceheating
Itisstronglyrecommendedtodischargeinternallyintothehouseholddrainagesystem.Ifconnectingtoarainwaterdrain,thatdrainMUSTdischargeintoafoul
drain.
i)Terminationtoaninternalsoilandventpipe