036-33072-001 Rev. A (0601)
Unitary Products Group
19
MAINTENANCE/SERVICE
FILTERS
Inspect filters monthly and replace as necessary. Use UL
Class 2 rated filters. Factory supplied filters are medium effi-
ciency, extended surface pleated type. Replacements should
be of the same type, to maintain optimum airflow perfor-
mance.
EVAPORATOR AND CONDENSER COILS
Inspect the evaporator coil at filter change intervals. Inspect
the condenser coil at least semi-annually. A dirty condenser
coil will result in elevated condensing pressures and poor unit
performance. Dirty or clogged evaporator coils causes low
suction pressure and lost capacity. If the coils appear dirty,
clean them using mild detergent or a commercial coil clean-
ing agent.
BLOWERS
Inspect both the evaporator and condenser blowers at each
regular service interval. Clean blower wheels as needed.
Bearings are permanently sealed ball type, and do not
require lubrication. Check bearings for any signs of wear (
movement between inner and outer races ). Ensure bearing
locking collars are secure to the shaft, and that collar locking
screw is properly set. Check that the blower wheel is tight on
the shaft, and that the hub set screws are properly torqued.
DRIVE BELTS
Examine belts periodically for wear. Glazed areas on the
drive surfaces indicate overheating due to belt slippage. Ideal
tension is the lowest tension at which the belt will not slip
under peak load conditions. Over-tensioning shortens belt
and bearing life.
The tension on the belt should be adjusted for a deflection of
1164 of an inch per inch of belt span, with the appropriate
force applied at the midpoint of the span. Tension "New" belts
at the maximum value indicated. Used belts should be main-
tained at the minimum value.
REFRIGERANT CIRCUIT(S)
With the unit operating, check and record the compressor
discharge and suction pressures. The compressor running
current should also be recorded. A maintenance 'og of these
readings can indicate if the unit is operating within it's normal
limits. Abnormal readings should be investigated, and the
Cause corrected.
DISCONNECT AND LOCK OUT POWER WHEN
SERVICING UNIT. FAILURE TO DO SO MAY
RESULT IN PERSONAL INJURY OR DEATH
DUE TO ELECTRICAL SHOCK.
Exercise care when working around the sharp
metal edges of door panels or door frames, etc.
These edges can cause injury.
WARNING
CAUTION
FIGURE 8 : TENSION INFORMATION
