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shouldbeused.Inordertopreventthe
buildupofscaleandcorrosiona
suitableinhibitorshouldbeused.The
systemmustbecorrectlyventedas
showninFigs.5and6.Theheight
differentialbetweentheheadertank
andtheappliancemustnotexceed
15.2metres(50feet).
Ifallfourboilertappingsareused
then,ifpossible,diagonalpairsshould
beconnectedfordomestichotwater
andcentralheating.Whereacommon
returnisusedaninjectorteemustbe
incorporatedintothesystemasshown
inFig.7.Thiswillensurethatagood
domestichotwatersupplyis
maintainedwhenthecentralheating
pumpisoperating.
Thesystemmustincorporateagravity
circuitwhichwillnormallyheatthe
domestichotwaterandanunvalved
radiatorwithanoutputofatleast1
kW.Whentheapplianceisnot
connectedtoadomestichotwater
systemtheunvalvedradiator(s)onthe
gravitycircuitmusthaveanoutputof
atleast1.25kW.Thisistoprevent
boilingincaseofpumpfailure.All
pipeworkintheprimarycircuitmust
be28mmdiameterandthegravity
flowpipemustrisecontinuouslyfrom
theboilertotheopenvent.Two
typicalsystemsareshowninFigures
5.and6.
Iftheapplianceisusedtoheatasmall
centralheatingsystemthentheheat
outputtotheroomfromthefirewill
bereduced.Fig.4.showstheratioof
spaceheatingtowaterheatingwhich
canbeexpected.
Fittingaradiatorinthesameroomas
thefireisrecommendedasitwill
allowgreaterflexibilityintheway
thatthesystemisoperatedaswellas
ensuringthatthereissufficientheat.
Connecttheheatingsystemtothe
boilerensuringthattheprimaryflow
piperisescontinuouslyfromthe
appliancetothevent.Fillthesystem
withwaterandcheckforleaks.
Thecirculatingpumpmaybe
controlledbymeansoftimeswitches,
roomthermostatsoroutdoor
thermostats.Radiatorsmaybeeither
manuallyorthermostatically
controlled.Thesecontrolswillall
workinconjunctionwiththe
thermostatontheapplianceandthe
lowlimitpipethermostat.
Werecommendfittingapipe
thermostatontothegravityreturnto
SYSTEMCONTROLS
Page6
Country14B09/03
CentralHeatingFlow
CentralHeatingReturn
DrainCockatLowestPoint
DrainCock
IndirectHotWaterCylinder
ColdWaterTank
Overflow
FeedandExpansionTank
22mmOpenVents
GravityRadiator
CirculatingPump
CentralHeatingReturn
DrainCockatLowestPoint
DrainCock
IndirectHotWaterCylinder
DomesticHotWaterDrawOff
ColdWaterTank
Overflow
Overflow
FeedandExpansionTank
22mmOpenVents
GravityRadiator
CirculatingPump
InjectorTee
MinimumReturnThermostat
GravityReturn
(28mmPipe)
CentralHeatingReturn
CommonReturntoBoiler
CentralHeatingFlow
MinimumReturn
Thermostat
(28mmPipe)
Overflow
DomesticHotWaterDrawOff
Fig.7.InjectorTee.
Using4BoilerTappings
Using3Tappings
Fig.5.TypicalCentralHeating&HotWaterSystem
Fig.6.TypicalCentralHeating&HotWaterSystem