507332-02G / 31-5000663
Page 32 of 35
Issue 2209
Service
ELECTRICAL SHOCK, FIRE, OR EXPLOSION
HAZARD
Failure to follow safety warnings exactly could result in
dangerous operation, serious injury, death or property
damage.
Improper servicing could result in dangerous operation,
serious injury, death, or property damage. Before
servicing, disconnect all electrical power to furnace.
When servicing controls, label all wires prior to
disconnecting. Take care to reconnect wires correctly.
Verify proper operation after servicing.
WARNING
At the beginning of each heating season, a qualified
technician should check the system as follows:
Blower
Check the blower wheel for debris and clean if necessary.
The blower motors are pre-lubricated for extended bearing
life. No further lubrication is needed.
The blower access panel must be securely in place
when the blower and burners are operating. Gas fumes,
which could contain carbon monoxide, can be drawn
into living space resulting in personal injury or death.
WARNING
Filters
Filters are installed external to the unit. Filters should
be inspected monthly. Clean or replace the filters when
necessary to ensure that the furnace operates properly.
Replacement filters must be rated for high velocity airflow.
Flue And Chimney
1.
Check flue pipe, chimney and all connections for
tightness and to make sure there is no blockage.
2. Check unit for proper draft.
Electrical
1. Check all wiring for loose connections.
2. Check for the correct voltage at the furnace (furnace
operating). Correct voltage is 120VAC.± 10%.
3. Check amp draw on the blower motor with inner blower
panel in place.
Unit Nameplate___________ Actual______________
Cleaning the Heat Exchanger and Burners
NOTE:
Use papers or protective covering in front of the
furnace during cleaning.
1.
Turn off both electrical and gas power supplies to
furnace.
2.
Remove flue pipe and top cap (some applications top
cap can remain) from the unit.
3. Label the wires from gas valve, rollout switches,
primary limit switch and make-up box then disconnect
them.
4. Remove the screws that secure the combustion air
inducer/pressure switch assembly to the collector box.
Carefully remove the combustion air inducer to avoid
damaging blower gasket. If gasket is damaged, it must
be replaced to prevent leakage.
5.
Remove the collector box located behind the
combustion air inducer. Be careful with the collector
box gasket. If the gasket is damaged, it must be
replaced to prevent leakage.
6. Disconnect gas supply piping. Remove the screw
securing the burner box cover and remove cover.
Remove the four screws securing the burner manifold
assembly to the vestibule panel and remove the
assembly from the unit.
7.
Remove screws securing burner box and remove
burner box.
8. NOX units only - Remove screw securing NOX insert.
Remove NOX insert. See Figure 29.
Figure 29. NOx Inserts
9. Remove screws from both sides, top and bottom of
vestibule panel.
10.
Remove heat exchanger. It may be necessary to
spread cabinet side to allow more room. If so, remove
five screws from the left side or right side of cabinet.
