Carrier 69NT20-531-300 manual Compressor OIL Level

n. Place the new service seals (kit item 2) at the com- pressor service ports, connect the four service valves loosely.

o.Torque the four resilient mount screws to 6.2 mkg (45 ft-lbs).

p.Torque the four service valves to:

Service Valve		Torque
Suction or Discharge		11 to 13.8 mkg
		(80 to 100 ft-lbs.)
Economizer		6.9 to 8.3 mkg
		(50 to 60 ft-lbs.)
Oil Return		1.4 to 1.66 mkg
		(10 to 12 ft-lbs.)
q. Reassemble	the top	mounting	bracket	(see
Figure 6-7)	by hand tightening the		32-mm	(1¼

-inch) bolt and torquing the four mounting screws to

0.9mkg (6.5 ft-lbs). Align the mounting so that the ring and bushing assembly are free with no compres- sion.

r.Torque the 32mm bolt to 1.5 mkg (11 ft-lbs.). While maintaining the free movement of the shock mount, torque the four mounting screws to 0.9 mkg (6.5 ft- lbs.).

s.Replace the power plug O-Ring with new ring (kit item 9). Insert the power plug into the compressor fit- ting. Be sure plug is fully seated into the fitting and then thread the coupling nut a minimum of 5 turns.

t.Leak check and evacuate the compressor to 1000 mi- crons. Refer to paragraphs 6.5 and 6.6

u.Run the unit for at least 15 minutes and check the oil and refrigerant levels. Refer to paragraphs 6.7 and 6.9.

6.9 COMPRESSOR OIL LEVEL

CAUTION

Use only Carrier Transicold approved Polyol Ester Oil (POE) - Mobil ST32 com- pressor oil with R-134a. Buy in quantities of one quart or smaller. When using this hygro- scopic oil, immediately reseal. Do not leave container of oil open or contamination will occur.

a. Checking the Oil Level in the Compressor

1Ideally, ambient temperature should be between 40_F and 100_F.

2Operate the unit in cooling mode for at least 20 min- utes.

3Check the controller function code Cd1 for the suc- tion modulation valve (SMV) position. It should be at least 20% open.

4Locate the oil sight glass on the side of the compres- sor (item 7, Figure 2-3).

5Turn Start/Stop switch off and allow oil to drain into compressor sump. Oil level must be visible in the sight glass. If it is not visible, oil must be added to the compressor.

b. Adding Oil with Compressor in System

1.The recommended method is to add oil using an oil pump at the oil return service valve (see item 15, Figure 2-3)

2.In an emergency where an oil pump is not available, oil may be drawn into the compressor through the oil return service valve.

Connect the suction connection of the gauge man- ifold to the compressor oil return valve port, and immerse the common connection of the gauge man- ifold in an open container of refrigeration oil. 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. Crack the oil return 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. Close the gauge manifold valve.

With the unit running, turn the suction service valve toward frontseat and induce a vacuum in the com- pressor crankcase. Do not allow the compressor to pull below 127mm/hg (5 “/hg). SLOWLY crack the suction gauge manifold valve and oil will flow through the oil return service valve into the compres- sor. Add oil as necessary.

3Run unit for 20 minutes in cooling mode. Check oil level at the compressor sight glass.

c. Removing Oil from the Compressor:

1If the oil level is above the sight glass, oil must be removed from the compressor.

2Perform a compressor pump down, refer to section 6.4.

3Remove the oil plug, and drain oil until a level can be seen in the sight glass.

4Run unit for 20 minutes in cooling mode. Check oil level at the compressor sight glass.

6.10 HIGH PRESSURE SWITCH

6.10.1 Replacing High Pressure Switch

a. Turn unit start-stop switch OFF. Frontseat the suc- tion, discharge, economizer and oil return service valves to isolate compressor. Remove the refrigerant from the compressor.

b. Disconnect wiring from defective switch. The high pressure switch is located on the discharge service valve and is removed by turning counterclockwise. (See Figure 2-3.)

c. Install a new high pressure switch after verifying switch settings. (Refer to paragraph 6.10.2.)

d. Evacuate and dehydrate the compressor per para- graph 6.6.

6-7 T-309