Gas Valve - Lennox G32 SERIES Unit Information

9.Blower Motors and Capacitors
All G32 units use direct drive blower motors. All motors used
are 120V permanent split capacitor motors to ensure maxi
mum efficiency. See table 11 for ratings.
TABLE 11
G32 BLOWER RATINGS 120V 1PH
BLOWER MOTOR
G32Q3
G32Q3/4
G32Q4/5
10.Combustion Air Blower (B6)
All G32 units use a two−stage combustion air blower to move
air through the burners and heat exchanger during heating op
eration. The blower uses a 120VAC motor. The motor oper
ates during all heating operation and is controlled by the Sur
eLight integrated control A92 and the two−stage control board
A86. The combustion air blower operates for 15 seconds be
fore burner ignition (pre purge) and for 5 seconds after the gas
valve closes (post purge). The combustion air blower operates
on low speed during first−stage heat (low fire), then switches to
high speed for second−stage heat (high fire).
11.Primary Limit Control (S10) Figure 15
The primary limit (S10) on G32 units is located in the middle
of the heating vestibule panel. When excess heat is
sensed in the heat exchanger, the limit will open. If the limit
is tripped, the furnace control energizes the supply air
blower and de−energizes the gas valve. The limit automati
cally resets when unit temperature returns to normal. The
switch is factory set and cannot be adjusted.
LIMIT CONTROL (S10) FOR
G32 SERIES UNITS AND ALTERNATE STYLE
Units may be equipped with either style limit.
INSULATING COVER (s)
FIGURE 15
HP CAP
1/3 5MFD 370V
1/2 7.5MFD 370V
3/4 40MFD 370V
12.Flame Rollout Switch (S47)
Flame rollout switch S47 is a SPST N.C. high temperature limit
located on the right side of the burner box assembly (see figure
16). S47 is wired to the burner ignition control A92. When
S47 senses flame rollout (indicating a blockage in the
combustion passages), the flame rollout switch trips,
and the ignition control immediately closes the gas
valve. Switch S47 in all G32 units is factory preset to open
at 200_F + 12_F (93_C + 6.7_C) on a temperature rise. All
flame rollout switches are manually reset.
FLAME ROLLOUT SWITCH (S47)

13.Gas Valve

The G32 uses a gas valve manufactured by White Rodgers
or Honeywell. The valve is two stage internally redundant
to assure safety shut−off. If the gas valve must be replaced,
the same type valve must be used. The Honeywell valve
can be field converted to LP and is adjustable on both high
fire and low fire. WhiteRodgers supplies two separate
valves for natural and LP and is adjustable on high fire
ONLY.
24VAC terminals and gas control knob are located on top of
the valve. Terminals on the gas valve are connected to wires
from the SureLight integrated control and the two−stage con
trol. 24V applied to the terminals energizes the valve.
Inlet and outlet pressure taps are located on the valve. A regu
lator adjustment screw is located on the side of the valve. Re
fer to figure 37 in section III−START UP for location of valve
features.
100% Sealed Combustion
The burner box is completely sealed and operates under a
negative pressure. A pressure hose is connected from the
burner box to the gas valve regulator and differential pres
sure switch. The gas valve senses the pressure in the burn
er box and changes gas valve output based on changes in
burner box pressure. The intent is to compensate for differ
ent vent configurations which can greatly affect the rate of
the unit.
Page 15
FLAME ROLLOUT
SWITCH (S47)
FIGURE 16