Lennox LGM156U Installation Instructions Manual page 40

IGNITOR
SPARK GAP
SHOULD BE
1/8" (3mm)
FIGURE 42
TABLE 22
Unit
Dimension
Btuh Input
A 260K
B 360K
C 480K
D-Combustion Air Inducer (Gas Units)
A combustion air proving switch checks combustion air
inducer operation before allowing power to the gas
controller. Gas controller will not operate if inducer is
obstructed.
IGNITOR
A
B
C
SIDE VIEW IGNITOR
1-3/8"
(35mm)
13/16"
(21mm)
LGM/LCM156, 180, 210, 240, 300
Length - in. (mm)
Ignitor Sensor
7-3/4 (197) 11 (279)
5 (127) 5-1/2 (140)
2-1/4 (57) 2-3/4 (70)
IGNITOR AND SENSOR POSITION
Gas Flow
Under normal operating conditions, the combustion air
inducer wheel should be checked and cleaned prior to the
heating season. However, it should be examined
periodically during the heating season to establish an
ideal cleaning
disconnected, the condition of the inducer wheel can be
determined by looking through the vent opening.
Clean combustion air inducer as follows:
1- Shut off power supply and gas to unit.
2- Disconnect
combustion air inducer port.
3- Remove and retain screws securing combustion
air inducer to flue box. Remove and retain two
screws from bracket supporting vent connector.
See figure 44.
4- Clean inducer wheel blades with a small brush and
wipe off any dust from housing. Clean accumulated
dust from front of flue box cover.
5- Return combustion air inducer motor and vent
connector to original location and secure with retained
screws. It is recommended that the combustion air
inducer gasket be replaced during reassembly.
6- Clean combustion air inlet louvers on heat access
panel using a small brush.
TOP VIEW
SIDE VIEW SENSOR
BURNER BOX
FIGURE 43
Page 40
schedule. With power
pressure switch air
SENSOR
A
B
C
Gas Flow
3/8"
(10mm)
supply
tubing from
1-3/4"
(45mm)