Lennox G32V Series Service Literature page 63

B−Sequence of Operation.
Sequence depends on type thermostat used. Units are
applicable for single stage or two stage thermostats.
Both type thermostats are described below. Thermo-
stat jumper E20 dictates which mode unit will operate
in. See flow chart for more sequence detail.
SureLight Control Self Check
When there is a call for heat, the SureLight integrated con-
trol runs a self check. The control checks for S10 primary
limit, S21 secondary limit (s) and S47 rollout switch normal-
ly closed contacts. The control also checks for prove switch
S102 and low heat prove switch S128 (G32V−75 only) nor-
mally open contacts. Once self check is complete and all
safety switches are operational, heat call can continue.
Two−Stage Thermostat, Two Stage Heat. Jumper E20
set at TWO".
1− SureLight control energizes combustion air inducer B6
on low heat speed. Combustion air inducer runs until
S102 prove switch contacts close (switch must close
within 2 1/2 minutes or control goes into Watchguard
PROVE Switch mode.
G32V−75 ONLY − Combustion air inducer runs until
S128 prove switch contacts close (switch must close
within 2 1/2 minutes or control goes into Watchguard
PROVE Switch mode. Prove switch S102 may also
close). A 15 second pre−purge follows once S128
closes.
2− SureLight control begins 20 second ignitor warm up pe-
riod.
3− Gas valve opens on first stage for a 4 second trial for
ignition. Ignitor stays energized during the trial or until
flame sensed.
4− Flame is sensed, gas valve remains on first stage heat,
ignitor de−energizes.
5− After 45 second delay, indoor blower B3 is energized
on low heat speed.
The furnace will stay in this mode until first stage de-
mand is satisfied OR a second stage heat demand is
initiated.
6− Second stage heat demand initiated. A 30 second sec-
ond stage recognition period begins.
7− The combustion air inducer ramps up to high heat
speed.
G32V−75 − S102 high heat prove switch closes.
8− Gas valve energizes second stage heat.
9− B3 indoor blower ramps up to high heat speed.
Single−Stage Thermostat, Two Stage Heat. Jumper
E20 set at SINGLE"
1− SureLight control energizes combustion air inducer B6
on low heat speed. Combustion air inducer runs until
S102 prove switch contacts close (switch must close
within 2 1/2 minutes or control goes into Watchguard
PROVE Switch mode.
G32V−75 ONLY − Combustion air inducer runs until
S128 prove switch contacts close (switch must close
within 2 1/2 minutes or control goes into Watchguard
PROVE Switch mode. Prove switch S102 may also
close). A 15 second pre−purge follows once S128
closes.
2− SureLight control begins 20 second ignitor warm up pe-
riod.
3− Gas valve opens on first stage for a 4 second trial for
ignition. Ignitor stays energized during the trial or until
flame sensed.
4− Flame is sensed, gas valve remains on first stage heat,
ignitor de−energizes.
5− After 45 second delay, indoor blower B3 is energized
on low heat speed.
6− A 10 minute (factory set) or 15 minute (field set) second
stage heat delay period begins.
7− The combustion air inducer ramps up to high heat
speed.
G32V−75 − S102 high heat prove switch closes.
8− Gas valve energizes second stage heat.
9− B3 indoor blower ramps up to high heat speed.
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