Carrier WeatherExpert 48N2 Controls, Start-Up, Operation, Service, And Troubleshooting page 170

3. See Fig. 53 and adjust fan height using a straight edge laid
across the fan deck.
4. Tighten setscrew to 12.5 to 13.75 ft-lb and replace rubber
hubcap to prevent hub from rusting to the motor shaft. Fill
hub recess with Permagum if hub has no rubber hubcap.
5. Replace fan guard.
Fig. 52 — Pulley Alignment
Fig. 53 — Condenser-Fan Adjustment
CONDENSER FAN ADJUSTMENT (PLASTIC FANS)
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 posi-
tioned as shown in Fig. 54. Tighten setscrews to 14  1 ft-lb
(18  1.3 N-m).
Check for proper rotation of the fan(s) once reinstalled (coun-
terclockwise viewed from above). If necessary to reverse,
switch leads at contactor(s) in control box.
FAN ORIFICE
Fig. 54 — Condenser Fan Position (Plastic Fan)
AIR PRESSURE TRANSDUCER FIELD ADJUSTMENT
All transducers have been factory calibrated and should not re-
quire 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. 55.
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. 55).
6. Reinstall the transducer in the unit.
7. Restore power to the unit.
TRANSDUCER INPUT
PART RANGE
NUMBER (in. wg)
HK05ZG019 0-5
HK05ZG020 0-1
HK05ZG022 –0.25-0.25
Fig. 55 — Transducer Details
170
PLASTIC FAN
PROPELLER
CLEARANCE OF 0.25 INCHES
(6.4 MM) FOR STANDARD
CONDENSER FANS
FAN DECK
SURFACE
OUTPUT OUTPUT
USAGE
RANGE AT 0 IN. WG
Air Foil
4-20 mA 4 mA
Fan Cfm
Return
4-20 mA 4 mA
Fan Cfm
Building
4-20 mA 12 mA
Pressure
HIGH
LOW
COM OUT EXC
S
Z