Compressor; Lubrication; Replacing Compressor; Compressor Rotation - Carrier 50GCQ Series Service And Maintenance Instructions

5 Ton 50GCQ / 549K / RHW
R-410A Refrigerant Charging Chart
(Unit must run in cooling mode, on high stage
compressors and outdoor fan on high speed.)
59.9 140
Add Charge if Above the Curve
120
48.8
37.7 100
26.6 80
15.5 60
4.4 40
–6.7 20
150 200 250
1034 1379 1723
Compressor Discharge Pressure, [psig/Kpa]
Fig. 24 — Cooling Charging Chart — 5 Ton

COMPRESSOR

Lubrication

The compressor is charged with the correct amount of oil at the
factory.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to
components.
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 atmosphere.
WARNING
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in death, serious
personal injury and/or property damage.
Never use air or gases containing oxygen for leak testing or for
operating refrigerant compressors. Pressurized mixtures of air
or gases containing oxygen can lead to an explosion.
Remove Charge if Below the Curve
300 350 400 450 500 550
2068 2413 2758 3102 3447 3792
48TC005888 REV -
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.
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
600
prevent POE oil from spilling onto the roof surface.
4136
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

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
certain compressor is rotating in the proper direction. To deter-
mine 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.
16
WARNING
CAUTION
CAUTION