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4- After the prepurge is complete and the pressure
switch is closed, a 20-second initial ignitor warm-up
period begins.
5 - After warm-up period, gas valve is energized on sec-
ond stage (high heat).
6 - Gas valve opens and gas is ignited. When flame is
established, flame sensor sends signal to control
module to de-energize the ignitor.
NOTE - If the flame is not detected after the first igni-
tion attempt, the control module de-energizes the
gas valve and the prepurge / ignition sequence is re-
peated. After five ignition trials without proof of
flame, the unit will go into a Watchguard / Flame Fail-
ure mode. In Watchguard mode, control will repeat
the prepurge and ignition trial sequence after 60 min-
utes of unsatisfied thermostat demand.
7 - After flame is sensed, 45-second FAN ON delay be-
gins. Indoor blower is energized on high heating
speed after delay. ACC and HTG ACC terminals are
energized.
8 - When heat demand issatisfied, gas valve is de-ener-
gized, combustion air inducer goes to 5-second
postpurge and adjustable FAN OFF delay begins.
B - Heating Sequence - Mode of Operation Jumper in
"W2 TIMED" Position
NOTE - To operate in this mode, the mode of operation
jumper on the two-stage control board must be in the "W2
TIMED" position. See figure 31.
1 - On call for heat from a single-stage thermostat,
operation sequence followssteps 1through4 as out-
lined above in single-stageheating sequence.
2 - Gas valveisenergizedonlow heat(firststage).Ignition
occursand signalis sentfrom control moduleto two-
stage controlboard to begin"W2 ON" delay (factory
set at 8 minutes).See figure 31 for delaysettings.
3 - "FAN ON" delay begins. When delay ends, indoor
blower motor isenergized on low speed.
4 - If the selected"W2 ON"delayends and the demand
for heat is still not satisfied, the two-stage control
switchesthe furnace tosecondstageoperation(high
heat). In second stage operation, the following oc-
cur: combustionair inducer motor is energized at
highspeed;indoorblowermotorisenergizedon high
heating speed; and gas valve is energized on high
heat after an 8-second delay.
5 - When the demand for heat is satisfied, the high- and
low-heat gas valves are de-energized, the combus-
tion air inducer goes into the 5-second post purge op
oration on low speed and the indoor blower motor
goes into the FAN OFF delay on low speed.
Applications Using A Two-Stage Thermostat
C - Heating Sequence - Mode of Operation Jumper in
"13NO-STAGE" Position (Factory Setting)
The sequence of operation is the same as outlined above
(in section B), except that low-heat and high-heat opera-
tion is controlled from the room thermostat.
1 - When the thermostat is set to "FAN ON," the indoor
blower will run on continuous fan speedwhen there is
no cooling or heating demand.
2 - When the G32 is running in the low heat (first stage)
mode, the indoor blower wilt run on continuous fan
speed.
3 - When the G32Q is running in the high heat (second
stage) mode, the indoor blower will run on the heat-
ing speed.
4 - When there is a cooling demand, the indoor blower
will run on the cooling speed.
Gas Flow
Tocheckfor propergas flowto the combustionchamber.
determinethe Btu(kW) inputfrom theunitratingplate.Di-
vide thisinputratingby the Btu (kW) per cubicfoot (cubic
meter) ofavailablegas. The resultisthe requirednumber
of cubicfeet (cubicmeter) perhour.Determinethe flowof
gas throughthe gas meterfor two minutesandmultiplyby
30 to get the houdy flowof gas.
Gas Pressure
1 - Check gas line pressurewith unitfiringat maximum
rate. A minimumof 4.5 in.w.c.(1.12 kPa)for natural
gas shouldbe maintained.
2 - Afterline pressure has been checkedand adjusted,
check highheatregulatorpressure.See figure34 for
gas pressureadjustment screw location.High heat
manifoldpressureis given intable 6.
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