Service - Lennox ML193UH Installation Instructions Manual

Service

WARNING
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 opera­
tion, serious injury, death, or property damage.
Before servicing, disconnect all electrical power to
furnace.
When servicing controls, label all wires prior to dis­
connecting. Take care to reconnect wires correctly.
Verify proper operation after servicing.
At the beginning of each heating season, system should be
checked as follows by a qualified service technician:
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 1 lists
recommended filter sizes.
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).
3 - Check amp-draw on the blower motor.
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.
Cleaning the Burner Assembly
1 - Turn off gas and electrical power to the furnace. Re­
move heating compartment access panel.
2 - Disconnect the gas supply line from the gas valve.
3 - Disconnect and label wires from gas valve.
4 - Disconnect ignitor wiring at 2 circuit plug.
5 - Disconnect and label wires from rollout switch.
6 - Disconnect and label flame sensor wire.
7 - Disconnect and label ground wire from burner/man­
ifold assembly.
8 - Remove four screws that secures burner/manifold as­
sembly to vestibule. Remove the assembly and make
note not to allow ignitor plate to dislodge from the as­
sembly.
9 - Gently clean the face of the burners using the soft
brush attachment on a vacuum cleaner. Visually in­
spect the inside of the burners and crossovers for any
blockage caused by foreign matter. Remove any
blockage
10 - Reinstall the burner/manifold assembly using the ex­
isting four screws. Burners are self aligning to cen­
ter of clam shells.
11 - Reconnect ground wire.
12 - Reconnect flame sensor wire.
13 - Reconnect rollout switch wires.
14 - Reconnect ignitor wires.
15 - Reconnect gas valve wires.
16 - Reconnect gas supply line to gas valve.
17 - Refer to instructions on verifying gas and electrical
connections when re-establishing supplies.
18 - Follow instructions to place furnace in operation. Run
furnace 5 minutes to ensure burners are clean and op­
erating correctly.
19 - Replace heating compartment access panel.
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