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HONEYWELL SV9541M "SMART VALVE" Sequence of Operation
I POWERAPPLIEDTO APPUANCE l
I THERMOSTAT CALLS FOR HEAT
¢
I PRESSURESWITCHESPROVEDOPEN?
i
I COMBUSTIONBLOWER ENERGIZED
I
PRESSURESWITCHESCLOSEDWITHIN30SEC-
ONDS?
3SECONDPRE-PURGE
PILOTVALVEOPENS:
IGNITORPOWERED(1)
PILOTLIGHTSANDFLAMEIS SENSED I_uI
DURING90SECONDTRAILFOR
IGNITION?
_I YES
MAINVALVE OPENS,
HEATING FAN "ON"DELAY BEGINS
AFTERDELAY:CIRCULATINGBLOWERSTARTS I
I
FLAME SENSE LOST?
THERMOSTAT CALL FOR HEAT ENDS
_ NO
IP,LOTANDMAINVALVECLOSE I
COMBUSTIONBLOWER DE- ENERGIZEDAFTER30
SECONDPOSTPURGE
ICIRCHLAT_NGBLOWEROFFAFTERDELAY I
/WA.FORNEXTCALLFORHEAT I
L l
I
WAITFORPRESSURESWITCHESTOOPEN
_1_ COMBUSTIONBLOWERDE- ENERGIZED
_[ FIVEMINUTEWAITPERIOD
I
LTHREE SECOND FLAMEFAILURERECYCLE DELAY
PILOTVALVECLOSES;
PILOTIGNITOROFF
YES
.[ PILOTANDMAINVALVECLOSE
FLAME SENSE LOST MORE THAN FIVE I
TIMESINTHISCALLFOR HEAT?
J--
NO
YES
J
I CIRCULATINGBLOWEROFF AFTER DELAY I
+
COMBUSTIONAIR BLOWEROFFAFTERPOST
PURGE
(1) Ignitor"ON" for first 30secondsoftrialfor ignition,then"OFF" for next 30seconds. If the pilot has
notlit,it turnsback"ON" for thefinal 30seconds. The pilot valveremainsenergizedduringtheentire
90second trialfor ignition.
NOTE:Ifmainlimitstring opensandtakes longerthan2 minutesto close,system goesintoI hourwait
period.
440O1102004 [_