Lennox G32V Series Service Literature page 35

6.Gas Valve
The G32V uses gas valves manufactured by White Rodg-
ers or Honeywell. The valves are two-stage internally re-
dundant to assure safety shut−off. If the gas valve must be
replaced, the same type valve must be used. The Honey-
well valve (figure 27) is adjustable on low fire and high fire
and is field convertible for LP. WhiteRodgers supplies two
separate valves for natural and LP (figures 28 and 29) .
White Rodgers valves are not adjustable on low fire.
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 control. 24V
applied to the terminals energizes the valve.
IMPORTANT
WhiteRodgers valve is NOT adjustable on low
fire. Do not attempt to adjust low fire on White-
Rodgers valve.
HONEYWELL VR8205 Series Gas Valve
HIGH FIRE
ADJUSTMENT
SCREW
(under cap)
lOW FIRE
ADJUSTMENT
SCREW
(under cap)
GAS VALVE SHOWN IN OFF POSITION
INLET PRESSURE TAP
FIGURE 27
WHITE RODGERS 36E SERIES GAS VALVE
NATURAL GAS
FIGURE 28
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.
Figure 30 show how gas valve output changes as burner
box pressure changes. Generally, a lower burner box
pressure produces a leaner gas/air mixture and a higher
burner box pressure produces a richer mixture. Burner
box pressure pressure will be between 0" and −1.0". Man-
MANIFOLD ifold pressure for natural units should be 3.5" W.C. + or −
PRESSURE
.30" and 7.0" W.C. + or − .30" for propane units. A proce-
TAP
dure showing how to check manifold pressure is shown on
page 32.
HIGH HEAT
MANIFOLD
PRESSURE
ADJUSTMENT
ON SIDE
(under cap)
MANIFOLD
PRESSURE
OUTLET ON
Gray area indicates normal operating range + 10% of manifold pres-
SIDE
sure.The purpose of this chart is to explain unit operation . Each unit
may vary depending on installation, altitude, intake/exhaust configu-
ration and other factors.
Page 35
WHITE RODGERS 36E SERIES GAS VALVE
PROPANE GAS
P M
HI
C
FIGURE 29
NORMAL OPERATION
3.5
OPERATION AT THIS EXTREME
MAY INDICATE A BLOCKED
3.4
INLET OR OTHER PROBLEM"
3.3
3.2
3.1
3.0
2.9
2.8
2.7
AOPERATION AT THIS EXTREME
2.6 MAY INDICATE A BLOCKED
OUTLET OR OTHER PROBLEM
2.5
−1.0 −0.8 −0.6
BURNER BOX PRESSURE
(Negative inches water gauge
measured on right side of burner box)
FIGURE 30
HIGH HEAT
MANIFOLD
PRESSURE
ADJUSTMENT
ON SIDE
(under cap)
MANIFOLD
PRESSURE
OUTLET ON
SIDE
−0.4 −0.2 0