129
CONDENSER FAN ADJUSTMENT (Sizes 050,070,075
With High-Capacity Evaporator Coil Option) — Each fan is
supported by a formed wire mount bolted to a fan deck and
covered with a wire guard. The exposed end of the fan motor
shaft is protected from weather by grease. If the fan motor must
be removed for service or replacement, be sure to regrease fan
shaft and reinstall fan cover, retaining clips, and fan guard. For
proper performance, the fans should be positioned as shown in
Fig. 47. Tighten setscrews to 14 ± 1 ft-lb (18 ± 1.3 N-m).
Check for proper rotation of the fan(s) once reinstalled
(counterclockwise viewed from above). If necessary to reverse,
switch leads at contactor(s) in control box.
AIR PRESSURE TRANSDUCER FIELD ADJUST-
MENT — All transducers have been factory calibrated and
should not require field adjustment. If field adjustment is
necessary, follow the instructions below. To re-calibrate a
transducer:
1. Shut the unit power off.
2. Take the wiring and pressure tubing off the transducer.
Take the transducer out of the unit.
3. Connect a 24-vdc power supply to transducer terminals
EXC(+) and COM(–). See Fig. 48.
4. Using a digital multimeter measure the current between
terminals EXC(+) and OUT.
5. With both pressure ports open to atmosphere adjust the
Zero (Z) screw potentiometer on the transducer and read
the multimeter until the desired current output at 0 in. wg
pressure is obtained (see Fig. 48).
6. Reinstall the transducer in the unit.
7. Restore power to the unit.
Cleaning — Inspect unit at the beginning of each heating
and cooling season and during each season as operating condi-
tions may require.
Clean condenser coil with a vacuum cleaner, fresh water,
compressed air, or a bristle brush (not wire). Coil cleaning
should be a part of the planned maintenance program. Clean
evaporator coil with a stiff bristle brush (not wire), vacuum
cleaner, or compressed air.
Check and clean condensate drain annually at the start of
the cooling season.
Replace return-air filters at the start of each heating and
cooling season or as often as necessary during each season, de-
pending on operating conditions.
1. Remove economizer outdoor-air filters from the hoods by
removing the filter retainers.
2. Clean filters with steam or hot water and mild detergent.
3. Reinstall filters in hoods after cleaning. Never replace
cleanable filters with throwaway filters.
PLASTIC FAN
PROPELLER
CLEARANCE OF 0.25 INCHES
(6.4 MM) FOR STANDARD
CONDENSER FANS
FAN DECK
SURFACE
FAN ORIFICE
Fig. 47 — Condenser Fan Position (Units with High
Capacity Evaporator Coil Option)
Fig. 45 — Pulley Alignment
Fig. 46 — Condenser-Fan Adjustment
(Standard Units)