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Failure to Operate
If unit fails to operate check the following:
1 - Is thermostat calling for heat?
2 - Is main disconnect switch closed?
3 - Is the circuit breaker open?
4 - Is filter dirty or plugged? Dirty or plugged filters will
cause unit to go off on limit control.
5 - Is gas turned on at meter?
6 - Is manual main shutoff valve open?
7 - Is internal manual shutoff valve open?
After items 1 through 7 have been checked and unit still will
not start, check for vent blockage and for proper draft. If unit
still does not start, reset rollout switch located over burners. If
unit starts and cuts out, check heat section for blockage.
CAUTION
Check pilot flame and burner flame periodically to
ensure proper operation.
Service
WARNING
Disconnect power before servicing unit.
CAUTION
Label all wires prior to disconnection when servic
ing controls. Wiring errors can cause improper and
dangerous operation. Verify proper operation after
servicing.
At the beginning of each heating season, the system
should be checked by a qualified service technician as fol
lows:
Blower
Check the blower wheels for debris and clean if neces
sary. The blower motors are prelubricated for extended
bearing life. No further lubrication is needed.
Filters
1 - Filters should be inspected monthly and must be
cleaned or replaced when dirty to assure proper fur
nace operation.
2 - Optional reusable foam filters for use with G23(X)
units can be washed with water and mild detergent.
When dry, they should be sprayed with filter handi
coater prior to reinstallation. Filter handicoater is RP
Products coating no. 418 and is available as Lennox
part no. P-8-5069.
3 - If replacement is necessary, order Lennox part no.
31J81 for 14 X 25 inch filter for Q2-50, Q3-50 and
Q2/3-75 units, P-8-7822 for 16 X 25 inch filter for
Q3-100 units, and P-8-7831 for 20 inch x 25 inch filter
used on Q3/4-100, Q3/4-125, Q4/5-75, Q4/5-100,
Q5/6-125 and Q5/6-150 units.
Flue and Chimney
Check flue pipe, chimney and all connections for tight
ness and to make sure there is no blockage.
Electrical Check
1 - Check all wiring for loose connections.
2 - Check for correct voltage at unit (unit operating).
3 - Check amp-draw on blower motor.
Motor Nameplate__________Actual__________
Cleaning Duralok
TM
Heat Exchanger and Burners
NOTE-Use papers or protective covering in front of fur
nace while cleaning furnace.
Cleaning the heat exchanger requires a steel spring
snake," a reversible drill and a vacuum cleaner. The steel
spring snake may be constructed by purchasing a 4 foot
long by 1/4 inch diameter steel wire cable and a 1/4 inch
diameter wire brush. These items are available at a hard
ware store. Insert wire end of brush into the open end of the
spring cable. Crimp the cable around the brush so that the
brush is secured and will not come off during cleaning. At
tach the other end of the cable to the reversible drill to com
plete the tool for cleaning the heat exchanger. See figure 1
for parts arrangement when disassembling furnace.
1 - Turn off both electrical and gas power supplies to
furnace.
2 - Remove flue pipe and top cap from unit. Mark and
disconnect wiring from pressure switch and ignition
control. Remove ignition control and pressure switch
from upper vestibule panel.
3 - Remove upper vestibule panel to expose the com
bustion air blower.
4 - Remove three screws securing the combustion air
blower. Carefully remove the combustion air blower
to avoid damaging blower gasket. If gasket is dam
aged, it must be replaced to prevent leakage.
5 - Remove collector box located behind combustion air
blower. Care must be taken to avoid damaging the
collector box gasket. If the gasket is damaged it must
be replaced to prevent leakage.
6 - Mark then disconnect wires from gas valve and roll-
out switch.
7 - Disconnect gas supply piping. Remove four screws se
curing the burner manifold assembly to the lower vesti
bule panel and remove the assembly from the unit.
