Replacing Compressor; Compressor Rotation; Filter Drier; Condenser-Fan Adjustment - Carrier 50FCQ 04-07 Series Service And Maintenance Instructions

WARNING
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in death, serious
personal injury and/or property damage.
Never use non-certified refrigerants in this product. Non-
certified refrigerants could contain contaminates that could
lead to unsafe operating conditions. Use ONLY refrigerants
that conform to AHRI Standard 700.

Replacing Compressor

NOTE: Only factory-trained service technicians should remove
and replace compressor units.
CAUTION
INSTALLATION SITE DAMAGE
Failure to follow this caution can result in damage to
equipment location site.
R-410A refrigerant contains polyolester (POE) oil that can
damage the roof membrane. Caution should be taken to
prevent POE oil from spilling onto the roof surface.
The factory also recommends that the suction and discharge
lines be cut with a tubing cutter instead of using a torch to
remove brazed fittings.

Compressor Rotation

CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution can result in premature wear and
damage to equipment.
Scroll compressors can only compress refrigerant if
rotating in the right direction. Reverse rotation for
extended times can result in internal damage to the
compressor. Scroll compressors are sealed units and
cannot be repaired on site location.
NOTE: When the compressor is rotating in the wrong direction,
the unit makes an elevated level of noise and does not provide
cooling.
On 3-phase units with scroll compressors, it is important to be cer-
tain compressor is rotating in the proper direction. To determine
whether or not compressor is rotating in the proper direction:
1. Connect service gauges to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pres-
sure should rise, as is normal on any start-up.
NOTE: If the suction pressure does not drop and the discharge
pressure does not rise to normal levels, the evaporator fan is prob-
ably also rotating in the wrong direction.
4. Turn off power to the unit.
5. Reverse any 2 of the 3 unit power leads.
6. Reapply electrical power to the compressor. The suction
pressure should drop and the discharge pressure should
rise which is normal for scroll compressors on start-up.
7. Replace compressor if suction/discharge pressures are not
within specifications for the specific compressor.
The suction and discharge pressure levels should now move to
their normal start-up levels.

Filter Drier

Replace whenever refrigerant system is exposed to atmosphere.
Only use factory specified liquid-line filter driers with working
pressures no less than 650 psig (4482 kPa).
EQUIPMENT DAMAGE
Failure to follow this caution can result in equipment damage.
Do not install a suction-line filter drier in liquid line. A liquid-
line filter drier designed for use with R-410A refrigerant is
required on every unit.

Condenser-Fan Adjustment

1. Shut off unit power supply. Install lockout tag.
2. Remove condenser-fan assembly (grille, motor, and fan).
See Fig. 28.
3. Loosen fan hub setscrews.
4. Adjust fan height by pushing fan until it stops on the fan
shaft.
5. Tighten set screw to 60 in.-lb (6.78 Nm).
6. Replace condenser-fan assembly. When replacing the
condenser-fan assembly follow the screw pattern sequence
shown in Fig. 29. The screws must be replaced in the
sequence shown in the figure.
Fig. 28 — Condenser Fan Adjustment
18
CAUTION