41
7) Starttheboilerusingthelightinginstructionsonpage40.Aftertheboilerispoweredup,itshouldgothrough
thefollowingsequence.
 SequenceDisplay Meaning
1 U.125 orBlank  Checkinginternalsoftware(power-uponly)
2 0.SWT  Boilerinstandby.SWT =SupplyWaterTemp.Nocallforheat.
  (Aftercallforheatfromheatingthermostat)
3 A.SWT Self-CheckonStart-up
4 5.SWT Blowerandcirculatoron.Checkingforadequateairow.
5 1.SWT Prepurge
6 2.SWT  Trialforignition
7 3.SWT  Flameestablished.Boilerrespondingtoacallforheat.
8) Uponinitialstart-up,thegastrainwillbelledwithair.Evenifthegaslinehasbeencompletelypurgedofair,
itmaytakeseveraltriesforignitionbeforeaameisestablished.Ifmorethan5triesforignitionareneeded,
itwillbenecessarytopresstheresetbuttontorestarttheboiler.Onceaamehasbeenestablishedfortherst
time,subsequentcallsforburneroperationshouldresultinaameonthersttry.
9) Inspecttheamevisiblethroughthewindow.Onhighretheameshouldbestableandmostlyblue
(Fig.10.1).Noyellowtippingshouldbepresent;however,intermittentecksofyellowandorangeintheame
arenormal.
10)Checktheinletpressureandadjustifnecessary.Verifythattheinletpressureisbetweentheupperandlower
limitsshownontheratingplatewithallgasappliancesonandoff.
Figure 10.1: CHG Burner Flame
warNINg
ThE COrrECT OuTlET PrEssurE fOr ThE gas ValVE has bEEN
faCTOry sET aND rEquIrEs NO fIElD aDJusTmENT. ThIs sETTINg Is
saTIsfaCTOry fOr bOTh NaTural gas aND PrOPaNE. aTTEmPTINg TO
aDJusT ThE OuTlET PrEssurE may rEsulT IN DamagE TO ThE gas
VALVE AND CAuSE PRoPERTy DAMAGE, PERSoNAL INjuRy oR LoSS oF
lIfE.