Lennox XC21 Installation Instructions Manual page 48

FAN MOTOR SURGE PROTECTION
Surge Protector (Metal Oxide Varistor − MOV) − A part
designed to protect electrical devices from voltage spikes
that are 3 to 4 times the normal circuit voltage (see figure
27 for illustration of component).
An MOV works as follows: It is essentially a batch of
metallic−oxide grains separated by insulating layers.
Repeated voltage surges break down the insulating layers,
lowering the overall resistance and eventually causing the
device to draw too much current and trip whatever
over−current protection is inherent in the system)
MOV Check: They are supposed to be located beyond the
line fuse (though possibly not always). In this case, where
the line fuse blows or circuit breaker trips but there is no
visible damage to the MOV(s), the simplest test may be to
just temporarily remove the MOV(s) and see if the problem
goes away.
See figure 1 for location of the Surge Protections device in
the unit control box area.
Figure 27. Fan Motor Surge Protection Device
506518−01
OUTDOOR UNIT MAINTENANCE
Maintenance and service must be performed by a qualified
installer or service agency. At the beginning of each
cooling season, the system should be checked as follows:
1. Outdoor unit fan motor is pre−lubricated and sealed.
No further lubrication is needed.
2. Visually inspect all connecting lines, joints and coils for
evidence of oil leaks.
3. Check all wiring for loose connections.
4. Check for correct voltage at unit (unit operating).
5. Check amperage draw on outdoor fan motor.
Motor Nameplate:_________ Actual:__________.
6. Inspect drain holes in coil compartment base and
clean if necessary.
NOTE - If insufficient cooling occurs, the unit should be
gauged and refrigerant charge should be checked.
Clean and inspect outdoor coil (may be flushed with a
water hose). Ensure power is off before cleaning.
NOTE It may be necessary to flush the outdoor coil
more frequently if it is exposed to substances which are
corrosive or which block airflow across the coil (e.g., pet
urine, cottonwood seeds, fertilizers, fluids that may contain
high levels of corrosive chemicals such as salts)
Sea Coast Moist air in ocean locations can carry salt,
which is corrosive to most metal. Units that are located
near the ocean require frequent inspections and
maintenance. These inspections will determine the
necessary need to wash the unit including the outdoor coil.
Consult your
intervals/procedures for your geographic area or service
contract.
INDOOR UNIT MAINTENANCE
1. Clean or change filters.
2. Lennox blower
permanently sealed. No more lubrication is needed.
3. Adjust blower speed for cooling. Measure the pressure
drop over the coil to determine the correct blower CFM.
Refer to the unit information service manual for pressure
drop tables and procedure.
4. Belt Drive Blowers − Check belt for wear and proper
tension.
5. Check all wiring for loose connections.
6. Check for correct voltage at unit. (blower operating)
7. Check amperage draw on blower motor.
Motor Nameplate:_________ Actual:__________.
1. Clean coil if necessary.
2. Check connecting lines, joints and coil for evidence of
oil leaks.
3. Check condensate line and clean if necessary.
Page 48
Outdoor Unit
Outdoor Coil
installing contractor
Indoor Unit
motors are prelubricated
Indoor Coil
for proper
and