Compressors; Condenser-Fan Adjustment; Troubleshooting Cooling System - Carrier WeatherExpert 50LC 14 Series Service And Maintenance Instructions

Compressors

LUBRICATION
Compressors are charged with the correct amount of oil at the
factory.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to com-
ponents.
The compressor is in a R-410A refrigerant system and uses
a polyolester (POE) oil. This oil is extremely hygroscopic,
meaning it absorbs water readily. POE oils can absorb
15 times as much water as other oils designed for HCFC
and CFC refrigerants. Avoid exposure of the oil to the at-
mosphere.
REPLACING COMPRESSOR
The compressor used with Puron refrigerant contains a POE
oil. This oil has a high affinity for moisture. Do not remove the
compressor's tube plugs until ready to insert the unit suction
and discharge tube ends.
1. Remove all sources of power to the unit. Install lock-out
tag.
2. Recover refrigerant using environmentally friendly
procedures.
3. Remove electrical wires from compressor terminal. Cau-
tion must be used when removing wires from compressor
terminals. Use pliers, gloves, safety glasses and do not
face directly towards the compressor terminals. Terminal
blow out could occur.
4. With refrigerant completely recovered, open both sides of
manifold gage set. Refrigerant system should now be at
ambient pressures.
5. Prior to applying heat and removing compressor, procure a
wet quenching cloth and fire extinguisher.
6. Using torch, heat compressor suction line and remove suc-
tion tube from compressor.
7. Using torch, heat compressor discharge line and remove
hot gas tube from compressor.
8. Remove system filter drier and replace with new.
9. Loosen four compressor retaining bolts and save compo-
nents for installation of new compressor.
10. Using proper lifting techniques or devices, remove com-
pressor from system.
Compressor mounting bolt torque is 65 to 75 in. lbs (7.3 to
8.5 Nm).
COMPRESSOR ROTATION
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 gages 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, then:
1. Note that the evaporator fan is probably also rotating in
the wrong direction.
2. Turn off power to the unit. Install lock-out tag.
3. Reverse any two of the unit power leads.
4. Reapply power to the compressor.
The suction and discharge pressure levels should now move to
their normal start-up levels.
NOTE: When the compressor is rotating in the wrong direction,
the unit makes an elevated level of noise and does not provide
cooling.
FILTER DRIER
Replace whenever refrigerant system is exposed to atmo-
sphere. Only use factory specified liquid-line filter driers with
working pressures no less than 650 psig. Do not install a suc-
tion-line filter drier in liquid line. A liquid-line filter drier de-
signed for use with Puron (R-410A) refrigerant is required on
every unit.

Condenser-Fan Adjustment

See Fig. 15.
1. Shut off unit power supply. Install lockout tag.
2. Remove condenser-fan assembly (grille, motor, and fan).
3. Loosen fan hub setscrews.
4. Adjust fan height as shown in Fig. 15.
5. Tighten setscrews to 84 in. lbs (9.5 Nm).
6. Replace condenser-fan assembly.
Fig. 15 — Condenser Fan Adjustment

Troubleshooting Cooling System

Refer to Table 1 for additional troubleshooting topics.
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