Lennox International Inc. 4HP18LT - Manual (Page 23)

506470-01 Issue 1007
MAINTENANCE
Before the start of each heating and cooling season, the
following service checks should be performed by a qualified
service technician.
Inspect and clean outdoor and indoor coils. The outdoor
coil may be flushed with a water hose.
NOTE: It may be necessary to flush the outdoor coil more
frequently if it is exposed to substances which are corrosive
or which block air flow across the coil (such as pet urine,
cottonwood seeds, etc...).
Visually inspect the refrigerant lines and coils for leakes.
Check wiring for loose connections.
Check voltage at the indoor and outdoor units (with units
operating).
Check amperage draw at the outdoor fan motor, compressor,
and indoor blower motor. Values should be compared with
those given on unit nameplate.
Check, clean (or replace) indoor unit filters.
Check the refrigerant charge and gauge the system
pressures.
Check the condensate drain line for free and unobstructed
flow. Clean drain line, if necessary.
Adjust blower speed for cooling. Measure the pressure drop
over the coil to determine the correct blower CFM.
Belt drive blowers: Check drive belt for wear and proper
tensions.
If insufficient cooling is reported, the unit should be gauged
and refrigerant charge checked (see Refrigerant Charging
on page 13).
Page 23
Before performing maintenance operations on system,
turn the electric power to unit OFF at disconnect
switch(es). Unit may have multiple power supplies.
Electrical shock could cause personal injury or death.
WARNING