Front View - Lennox G17Q2-50 Unit Information

ROBERTSHAW IGNITION CONTROL
FIGURE 6
G-Gas Valve
The G17 uses a gas valve manufactured by Robertshaw or
Honeywell. The valve is internally redundant to assure safety
shut-off. If the gas valve must be replaced, the same type
valve must be used.
24VAC terminals and gas control knob are located on top of
the valve. All terminals on the gas valve are connected to
wires from the electronic ignition control. 24V applied to termi
nal P" energizes the pilot valve. An orange sensing wire from
terminal V"(marked VALVE SENSE) of the BCC2-2 control
rides piggy back" on the P" terminal connection. 24V applied
to terminal M" energizes the main valve. Terminal C" pro
vides 24V common.
Inlet and outlet pressure taps are located on the valve. A
pilot adjusting screw and regulator adjustment screw (fig
ures 7 and 9) are located on the valve. Refer to figure 8 for
exact location of valve features.
TYPICAL ACCESS TO REGULATOR
FOR ADJUSTMENT AND L.P. CHANGEOVER
(Robertshaw 7200 gas valve shown)
REGULATOR
COVER SCREW
GAS VALVE
SELECTOR
ARM
IN OFF
POSITION
FIGURE 7
An LPG changeover kit is available from Lennox. The kit in
cludes main and pilot burner orifices, burner air adjustment
shutters and a regulating conversion kit.
MAIN AND PILOT
VALVE COMMON
24VAC OUTPUT
TO MAIN VALVE
24VAC OUTPUT TO PILOT
24VAC INPUT FROM BCC2-2
MICROAMP SIGNAL
FROM FLAME
SENSOR
COMMON
HIGH VOLTAGE
TO SPARK IGNITOR
ADJUSTING
SCREW
SPRING
TYPICAL GAS VALVE COMPONENTS
(Robertshaw 7100 gas valve shown)
GAS VALVE KNOB SHOWN IN
OFF POSITION
INLET
PRESSURE
TAP
VALVE
INLET
FRONT
VIEW
ADJUSTMENT SCREW
TYPICAL ACCESS TO REGULATOR
FOR ADJUSTMENT AND L.P. CHANGEOVER
(Honeywell VR8204 series gas valve shown)
GAS VALVE SHOWN IN OFF POSITION
PRESSURE
REGULATOR
ADJUSTING SCREW
(White)
Page 5
ON
P C M
OFF
TOP VIEW
OUTLET
PRESSURE
TAP
PILOT PRESSURE REGULATOR
ADJUSTMENT SCREW
FIGURE 8
ON
OFF
CAP SCREW
(Black)
SPRING
Tapered End
GAS INLET
FIGURE 9
VALVE
OUTLET
Down
(Red)
INLET
PRESSURE
TAP