Carrier 69NT40-511-1 manual To Check Filter-Drier, To Replace Filter-Drier, High Pressure Switch

suction service valve flange cavity or by removing the oil fill plug. (See Figure 6-5.) Some compressors have the oil plug located on the crankcase, at the right or left side of the oil pump.

d. To Remove Oil From an 06DR Compressor:

1.If the oil level recorded in step a.3 is above one-eighth level of the capacity of the sight glass, oil must be removed from the compressor.

2.Close (frontseat) suction service valve and pump unit down to 1.2 to 1.3 kg/cm@ (2 to 4 psig). Frontseat discharge service valve and slowly bleed remaining refrigerant.

3.Remove the oil drain plug on the bottom plate of the compressor and drain the proper amount of oil from the compressor to obtain the correct level (maximum is one-eight level of the sight glass). Replace the plug securely back into the compressor.

DO NOT FORGET TO OPEN SUCTION AND DISCHARGE SERVICE VALVES.

4.Repeat step (a) to ensure proper oil level.

6.11 FILTER-DRIER

On units equipped with a water-cooled condenser, if the sight glass appears to be flashing or bubbles are constantly moving through the sight glass when the suction modulation valve is fully open, the unit may have a low refrigerant charge or the filter-drier could be partially plugged.

6.12 HIGH PRESSURE SWITCH

6.12.1 Replacing High Pressure Switch

a.Turn unit start-stop switch OFF. Frontseat both suction and discharge 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 center head and is removed by turning counterclockwise. (See Figure 2-1.)

c.Install a new high pressure switch after verifying switch settings. (Refer to section 6.12.2.)

d.Evacuate and dehydrate the compressor per section 6.5.1.

6.12.2Checking High Pressure Switch

WARNING

Do not use a nitrogen cylinder without a pressure regulator. Do not use oxygen in or near a refrigeration system as an explosion may occur.

NOTE

The high pressure switch (HPS) is non-adjustable.

a.Remove switch as outlined in section 6.12.1.

b.Connect ohmmeter or continuity light across switch terminals. Ohm meter will indicate no resistance or continuity light will be illuminated if the switch closed after relieving compressor pressure.

To Check Filter-Drier:

a. Test for a restricted or plugged filter-drier by feeling

c.Connect hose to a cylinder of dry nitrogen. (See Figure 6-17.)

the liquid line inlet and outlet connections of the

drier cartridge. If the outlet side feels cooler than the

inlet side, then the filter-drier should be changed.

b. A second test for moisture in the filter-drier is that

the moisture-liquid indicator shows moisture in the

system.

To Replace Filter-Drier:

a. Pump unit down to 0 psi and replace filter-drier.

(Refer to section 6.3.)

1

2

3

4

5

6

1.Cylinder Valve and Gauge

2.Pressure Regulator

3.Nitrogen Cylinder

4.Pressure Gauge (0 to 36 kg/cm@ = 0 to 400 psig)

5.Bleed-Off Valve

6.1/4 inch Connection

b.	Evacuate the unit per section 6.5 and open the
	manual liquid line valve.
c.	After unit is in operation, inspect for moisture in
	system.

Figure 6-17. Typical Setup for Testing

High Pressure Switch

d.Set nitrogen pressure regulator at 26.4 kg/cm@ (375 psig) with bleed-off valve closed.

e.Close valve on cylinder and open bleed-off valve.

SECTION 6

6-15 T-268-07