Carrier SUPRA 950Mt, Operation & Service Manual

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5.9 COMPRESSOR OIL LEVEL
5.9.1 Checking Oil Level in 05G Compressor
a. Operate the unit in high-speed cooling or heating for a run time of at least 20 minutes.
b. Check the oil sight glass on the compressor to ensure that no foaming of the oil is present after 20 minutes of oper-
ation. If the oil is foaming excessively after 20 minutes of operation, check the refrigerant system for flood-back of
liquid refrigerant. Correct this situation before performing step 3.
c. Check the level of the oil in the front sight glass with the compressor operating. The correct level should be
between the bottom and one-quarter of the sight glass. If the level is above one-quarter, oil must be
removed from the compressor. To remove oil from the compressor, follow step d. If the level is below sight
glass, add oil to the compressor following
Section 5.9.2 .
5.9.2 Adding Oil with Compressor in System
There are two methods for adding oil − the oil pump method and the closed system method.
a. Oil Pump Method
While Carrier does not provide an oil pump with the 950MT, there are a number of commercially-available pumps,
including a Robinair refrigerant oil pump (part number 14388), that can be used. This pump adapts to a one U.S.
gallon (3.785 liters) metal refrigeration oil container and pumps 2-1/2 ounces (0.0725 liters) per stroke when con-
nected to the suction service valve port. Also, there is no need to remove pump from the can after each use.
When the compressor is in operation, the pump check valve prevents the loss of refrigerant, while allowing service-
men to the ability to develop sufficient pressure to overcome the operating suction pressure and add oil necessary.
1. Backseat the suction service valve and connect oil charging hose to port.
2. Crack the service valve and purge the oil hose at oil pump.
3. Add oil as necessary.
b. Closed System Method
In an emergency where an oil pump is not available, oil may be drawn into the compressor through the suction ser-
vice valve.
CAUTION
!
Extreme care must be taken to ensure the manifold common connection remains immersed in
oil at all times. Otherwise air and moisture will be drawn into the compressor.
1. Connect the suction connection of the gauge manifold to the compressor suction service valve port, and
immerse the common connection of the gauge manifold in an open container of refrigeration oil.
2. Crack the suction service valve and gauge valve to vent a small amount of refrigerant through the common
connection and the oil to purge the lines of air.
3. Close the gauge manifold valve.
4. With the unit running, frontseat the suction service valve and pull a vacuum in the compressor crankcase.
5. Slowly crack the suction gauge manifold valve and oil will flow through the suction service valve into the
compressor. Add oil as necessary.
5.9.3 Adding Oil to Service Replacement Compressor
Service replacement compressors may or may not be shipped with oil.
If compressor is without oil:
Add correct oil charge by removing the oil fill plug (Refer to Section 2.7.4 , Section 5.7.1 and Section 5.7.2 ; see Fig-
ure 5.8 ).