HONEYWELL SV9541M "SMART VALVE" Sequence of Operation
I POWERAPPLIEDTO APPUANCE l
I THERMOSTAT CALLS FOR HEAT
¢
I PRESSURESWITCHESPROVEDOPEN?
i
I COMBUSTIONBLOWER ENERGIZED
I
PRESSURESWITCHESCLOSEDWITHIN30 SEC-
ONDS?
3SECONDPRE-PURGE
PILOTVALVEOPENS:
IGNITORPOWERED(1)
PILOT LIGHTSAND FLAMEIS SENSED I_uI
DURING90 SECONDTRAILFOR
IGNITION?
_I YES
MAIN VALVE OPENS,
HEATING FAN "ON" DELAY BEGINS
AFTERDELAY:CIRCULATINGBLOWERSTARTS I
I
FLAME SENSE LOST?
THERMOSTAT CALL FOR HEAT ENDS
_ NO
IP,LOTANDMAINVALVECLOSE I
COMBUSTIONBLOWER DE- ENERGIZEDAFTER 30
SECONDPOSTPURGE
ICIRCHLAT_NGBLOWEROFFAFTERDELAY I
/WA.FORNEXTCALLFORHEAT I
L l
I
WAITFOR PRESSURESWITCHESTOOPEN
_1_ COMBUSTIONBLOWERDE- ENERGIZED
_[ FIVEMINUTEWAITPERIOD
I
L THREE SECOND FLAMEFAILURERECYCLE DELAY
PILOTVALVECLOSES;
PILOTIGNITOROFF
YES
.[ PILOTAND MAINVALVECLOSE
FLAME SENSE LOST MORE THAN FIVE I
TIMES INTHISCALL FOR HEAT?
J--
NO
YES
J
I CIRCULATINGBLOWEROFF AFTER DELAY I
+
COMBUSTIONAIR BLOWEROFFAFTERPOST
PURGE
(1) Ignitor "ON" for first 30 seconds of trial for ignition,then "OFF" for next 30 seconds. If the pilot has
notlit, it turnsback"ON" for thefinal 30seconds. The pilot valve remains energizedduring the entire
90 second trial for ignition.
NOTE: If mainlimitstring opensandtakes longerthan 2 minutesto close,system goes intoI hourwait
period.
[_ 440 01 1020 05
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