Lennox G21Q3-40 User Manual

Page 61
It is normal for the
electrode to protrude
at an unusual angle
GAP
0.115" +0.000"
−0.010"
APPROX. 45°
ELECTRICAL TESTING
CHECKING FOR OPEN SWITCH
CHECKING VOLTAGE AT PURGE BLOWER
CHECKING FOR OPEN SWITCH
IN LIMIT CONTROL
SPARK PLUG
AIR INTAKE CHAMBER
TO FLUE
DIFFERENTIAL
PRESSURE SWITCH
R x 1
READ 0 OHMS
FOR CONTINUITY
AIR
INTAKE
4
CERAMIC
RESISTOR
TYPE
NOTE− CARBON RESISTOR TYPE
PLUGS
SHOULD NOT BE USED.
10
1
23
456
WIRING
HARNESS
120VAC?
120VAC?
8
9
AIR INTAKE CHAMBER
R x 1
READ 0 OHMS
FOR
CONTINUITY
AIR
INTAKE
5
PRIMARY
LIMIT CONTROL
TRACE LIMIT WIRE TO
CONTROL BOX. WIRE NUT
CONNECTION FOR METER
LEAD TEST POINT.
ORANGE
LIMIT
WIRES
PURGE BLOWER
WHITE (NEUTRAL)
RED*
*NOTE−RED WIRE GOES
TO PRIMARY CONTROL
HARNESS JP72−5.
PRIMARY CONTROL
WIRING HARNESS PLUG
(JP72)
CHAMPION FI21500
or equivalent only
TO FLUE
CHECK VOLTAGE AT TERMINAL AND
CHECKING THERMOSTAT DEMAND
CHECKING VOLTAGE AT GAS VALVE
24VAC DURING
IGNITION TRIALS?
GAS VALVE
3
LOW VOLTAGE TERMINAL STRIP WITH 3 AMP FUSE
LOCATED ON CONTROL BOX
1
2
24VAC
WITH DEMAND?
24VAC
POWER?
W1
W2
G
Y1
Y2
DS
CR
NM
CHECKING VOLTAGE AT PRIMARY CONTROL
1
23
456
LOW VOLTAGE TERMINAL
STRIP WITH 3 AMP FUSE
LOCATED ON CONTROL BOX
24VAC?
24VAC?
6
7
PRIMARY CONTROL
WIRING HARNESS PLUG (JP1)
W1
W2
G
Y1
Y2
DS
CR
NM
MANUAL−RESET
SECONDARY LIMIT*
REVERSE FLOW
APPLICATION ONLY
*Secondary limit on CGA
units may be
manual−reset or
auto−reset.

Lennox G21Q3-40 Specifications

General

Brand	Lennox
Model	G21Q3-40
Category	Industrial Equipment
Language	English