ICP 9MPD - Sequence of Operation

HONEYWELL SV9541M "SMART VALVE" Sequence of Operation
IPOWERAPPLIEDTO APPLIANCE
+
I THERMOSTATCALLS FORHEAT
¢
IPRESSURE SWITCHES PROVED OPEN?
ICOMBUSTIONBLOWER ENERGIZED
PRESSURESWITCHESCLOSEDWITHIN30 SEC-
ONDS?
+
I 3SECONDPRE-PURGE
PILOTVALVEOPENS:
IGNITORPOWERED(1)
PILOTLIGHTSAND FLAME ISSENSED l'_Vl
DURING 90 SECOND TRAILFOR
IGNITION?
I YES
MAINVALVEOPENS,
HEATINGFAN"ON" DELAYBEGINS
+
IAFTERDELAY:CIRCULATINGBLOWERSTARTS I
YES
FLAME SENSE LOST? I I
THERMOSTATCALL FORHEAT ENDS
NO
PILOTAND MAINVALVECLOSE
+
COMBUSTIONBLOWER DE- ENERGIZEDAFTER 30
SECONDPOST PURGE
+
I CIRCULATINGBLOWEROFF AFTER DELAY
I
I WAITFOR NEXTCALL FOR HEAT
I
I
WAIT FORPRESSURESWITCHESTOOPEN
_._ COMBUSTIONBLOWERDE-ENERGIZED
J__ FIVEMINUTE WAITPERIOD
I
THREESECONDFLAME ,J_
FAILURERECYCLEDELAY
PILOTVALVECLOSES;
PILOTIGNITOROFF
PILOTAND MAINVALVECLOSE 1
L FLAMESENSELOST MORETHAN FIVETIMESIN THIS CALL FORHEAT?
NO
YES
r
CIRCULATINGBLOWEROFFAFTER DELAY
+
COMBUSTIONAIRBLOWEROFF AFTERPOST
PURGE
I
(1) Ignitor "ON" for first 30 seconds of trial for ignition, then "OFF" for next 30 seconds. If the pilot has
not lit, it turns back "ON" for the final 30 seconds. The pilot valve remains energized during the entire
90 second trial for ignition.
NOTE: If main limit string opens and takes longer than 2 minutes to close, system goes into I hour wait
period.
[_ 44001 111400