ICP N9MP2125J20A1 - Sequence of Operation

HONEYWELL SV9541M "SMART VALVE" Sequence of Operation
POWER APPLIED TO APPLIANCE
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THERMOSTAT CALLS FOR HEAT
¢
PRESSURE SWITCHES PROVED OPEN?
COMBUSTION BLOWER ENERGIZED
PRESSURE SWITCHES CLOSED WITHIN
30 SECONDS?
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I 3 SECOND PRE-PURGE
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PILOT VALVE OPENS:
IGNITOR POWERED (1)
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PILOT LIGHTS AND FLAME IS SENSED
DURING 90 SECOND TRAIL FOR
IGNITION?
YES
MAIN VALVE OPENS,
HEATING FAN "ON" DELAY BEGINS
AFTER DELAY: CIRCULATING BLOWER
STARTS
FLAME SENSE LOST?
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THERMOSTAT CALL FOR HEAT ENDS
_ NO
PILOT AND MAIN VALVE CLOSE
COMBUSTION BLOWER DE-ENER-
GIZED AFTER 30 SECOND POST PURGE
CIRCULATING BLOWER OFF AFTER
DELAY
V
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WA,TFORPRESSURESW,TOHESTOOPENI
COMBUSTION BLOWER DE-ENERGIZED
FIVEMINUTEWAITPERIOD
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THREE SECOND FLAME [_
FAILURE RECYCLE DELAY
YES
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PILOTVALVECLOSES;
PILOTIGNITOROFF
PILOT AND MAIN VALVE CLOSE
V
FLAME SENSE LOST MORE THAN FIVE |
TIMES INTHIS CALL FOR HEAT?
YES
r
CIRCULATING BLOWER OFF AFTER
DELAY
COMBUSTION AIR BLOWER OFF AFTER
POST PURGE
WAIT FOR NEXT CALL FOR HEAT I
(1) Ignitor "ON" for first 30 seconds oftrial for ignition, then "OFF" for next 30 sec-
onds. 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 1 hour wait period.
440 01 101004 [_