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HEATINGSEQUENCECONTINUED
NORMALHEATINGMODE ABNORMALHEATINGMODE
I PRESSURESWtTCHCLOSED?
! 11
L'WO'STAGE'OOEI S,N";L;'S_;_%T
CALLFOR2ridSTAGE 2ridSTAGEON DELAY
HEAT(HIGHHEAT) ON CONTROLBOARD
FROM THERMOSTAT COMPLETE (B, 12 OR 15 MIN
I INDOOR BLOWER ON
HIGH HEATING SPEED?
1
I COMBUSTION AIR BLOWER ON HIGH
SPEED?
I HIGH HEAT PRESSURE SWITCH CLOSED? I
YES _
I HIGH HEAT GAS VALVE OPEN? (8 SEC. DELAY) _'NO
CONTROL CHECKS: FLAME PRESENCE, CLOSED I
PRIMARY LIMIT, CLOSED PRESSURE SWITCHES,
r
CONTINUOUSLY CLOSED ROLl.OUT SWITCH
(dudng heating cycle).
SEE PREVIOUS SEQUENCES FOR FAILURE MODES.
DEMAND FOR HEAT SATISFIED.
THERMOSTAT OPENS.
GAS VALVE DE-ENERGIZED.
COMBUSTION AIR BLOWER
POST-PURGE - 5 SECONDS.
INDOOR BLOWER
SELECTED TIME OFF DELAY.
I PREPURGE
(See top of previous page.)
GAS VALVE DE-ENERGIZED.
INDOOR BLOWER DE-ENERGIZED,
COMBUSTION AIR INDUCER ON FOR 2.5 MINUTES,
PRESSURESW,TC cLOSEO?
:__o
PRESSURE SWITCH WATCHGUARD
COMBUSTION AIR INDUCER
DE-ENERGIZED.
5-MINUTE DELAY
2.5
MINUTES
I
]
I
J
COMBUSTION AIR I
iNDUCER ON.
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