3
UNIT ARRANGEMENT AND
ACCESS
General
Fig. 1 and Fig. 2 show general unit arrangement and
access locations.
OUTDOOR AIR
HOOD
CONTROL BOX
ACCESS PANEL
RETURN AIR
FILTER AND 
INDOOR COIL
ACCESS PANEL
SUPPLY FAN
HEATING SECTION
GAS SECTION
ACCESS PANEL
OUTDOOR
FANS/MOTORS
DISCONNECT
CONVENIENCE
OUTLET
COMPRESSOR
(CIRCUIT A)
CONDENSER
COIL
(CIRCUIT A)
C12560
Fig. 1 − Access Panels and Components, Front
CONDENSER COIL
CIRCUIT A
CONDENSER COIL
CIRCUIT B
COMPRESSOR
CIRCUIT B
C09505
Fig. 2 − Typical Access Panel Locations, Rear
Routine Maintenance
These items should be part of a routine maintenance
program, to be checked every month or two, until a
specific schedule for each can be identified for this
installation:
Quarterly Inspection (and 30 days after initial start)
The 48TC units should be inspected and serviced every
three months.
 Return air filter replacement
 Outdoor hood inlet filters cleaned
 Belt tension checked
 Belt condition checked
 Pulley alignment checked
 Fan shaft bearing locking collar tightness checked
 Condenser coil cleanliness checked
 Condensate drain checked
Seasonal Maintenance
These items should be checked at the beginning of each
season (or more often if local conditions and usage
patterns dictate):
Air Conditioning
 Condenser fan motor mounting bolts tightness
 Compressor mounting bolts
 Condenser fan blade positioning
 Control box cleanliness and wiring condition
 Wire terminal tightness
 Refrigerant charge level
 Evaporator coil cleaning
 Evaporator blower motor amperage
Heating
 Heat exchanger flue passageways cleanliness
 Gas burner condition
 Gas manifold pressure
 Heating temperature rise
Economizer or Outside Air Damper
 Inlet filters condition
 Check damper travel (economizer)
 Check gear and dampers for debris and dirt
Air Filters and Screens
Each unit is equipped with return air filters. If the unit has
an economizer, it will also have an outside air screen. If a
manual outside air damper is added, an inlet air screen
will also be present.
Each of these filters and screens will need to be
periodically replaced or cleaned.
Return Air Filters
Return air filters are disposable fiberglass media type.
Access to the filters is through the small lift−out panel
located on the rear side of the unit, above the
evaporator/return air access panel. (See Fig. 1.)
EQUIPMENT DAMAGE HAZARD
Failure to follow this CAUTION can result in
premature wear and damage to equipment.
DO NOT OPERATE THE UNIT WITHOUT THE
RETURN AIR FILTERS IN PLACE. Dirt and
debris on heat exchangers and coils can cause
excessive current use, resulting in motor failure.
CAUTION
!