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Blower
Check the blower wheel for debris and clean if necessary.
The blower motors are prelubricated for extended bearing
life. No further lubrication is needed.
WARNING
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 inju
ry or death.
Filters
All air filters are installed external to the unit. Filters should
be inspected monthly. Clean or replace the filters when
necessary to ensure proper furnace operation. Table 24
lists recommended filter sizes.
IMPORTANT
If a highefficiency filter is being installed as part of
this system to ensure better indoor air quality, the fil
ter must be properly sized. Highefficiency filters
have a higher static pressure drop than standardef
ficiency glass/foam filters. If the pressure drop is too
great, system capacity and performance may be re
duced. The pressure drop may also cause the limit to
trip more frequently during the winter and the indoor
coil to freeze in the summer, resulting in an increase
in the number of service calls.
Before using any filter with this system, check the
specifications provided by the filter manufacturer
against the data given in the appropriate Lennox
Product Specifications bulletin. Additional informa
tion is provided in Service and Application Note
ACC002 (August 2000).
TABLE 24
Furnace
Cabinet Width
Filter Size
Side Return
Bottom Return
17-1/2”
16 X 25 X 1 (1)
16 X 25 X 1 (1)
21”
16 X 25 X 1 (1)
20 X 25 X 1 (1)
24-1/2”
16 X 25 X 1 (2)
24 X 25 X 1 (1)
Exhaust and air intake pipes
Check the exhaust and air intake pipes and all connections
for tightness and to make sure there is no blockage.
NOTE
- After any heavy snow, ice or frozen fog event the
furnace vent pipes may become restricted. Always check
the vent system and remove any snow or ice that may be
obstructing the plastic intake or exhaust pipes.
Electrical
1 - Check all wiring for loose connections.
2 - Check for the correct voltage at the furnace (furnace
operating). Correct voltage is 10%
3 - Check amp-draw on the blower motor with blower ac
cess panel in place.
Motor Nameplate__________Actual__________
Winterizing and Condensate Trap Care
1 - Turn off power to the furnace.
2 - Have a shallow pan ready to empty condensate water.
3 - Remove the clean out cap from the condensate trap
and empty water. Inspect the trap then reinstall the
clean out cap.
Condensate Hose Screens (Figure 65)
Check the condensate hose screens for blockage and
clean if necessary.
1 - Turn off power to the unit.
2 - Remove hoses from cold end header box. Twist and
pull screens to remove.
3 - Inspect screens and rinse with tap water if needed.
4 - Reinstall screens, reconnect hoses and turn on power
to unit.
FIGURE 65
Condensate Hose Screens
Hose
Hose
Cleaning Heat Exchanger
If cleaning the heat exchanger becomes necessary, follow
the below procedures and refer to figure 1 when disassem
bling unit. Use papers or protective covering in front of fur
nace while removing heat exchanger assembly.
1 - Turn off electrical and gas supplies to the furnace.
2 - Remove the burner access panel.
3 - Mark all gas valve wires and disconnect them from
valve.
4 - Remove gas supply line connected to gas valve.
5 - Remove sensor wire from flame sensor. Disconnect
2‐pin plug from the ignitor.
6 - Disconnect wires from flame roll-out switches.
7 - Remove four burner assembly screws at the vestibule
panel and remove gas valve /manifold and burner box
as a single unit.
NOTE
- If necessary, clean burners at this time. Follow
procedures outlined in Burner Cleaning section.
9 - Remove the clean-out cap on trap and drain. Replace
cap.
10 - Disconnect condensate drain line from the conden
sate trap. Remove condensate trap (it may be neces
sary to cut drain pipe). Remove the 1/2” NPT fitting
from the cold end header box. Disconnect drain tubes
from cold end header collector box.
11 - Disconnect condensate drain tubes from flue collar.
Remove screws that secures flue collar in place. Re
move flue collar. It may be necessary to cut the exiting
exhaust pipe for removal of the fitting.
12 - Loosen two clamps from flexible no-hub exhaust col
lar.
