Figure 2-4. Compressor Oil Level Sight Glass

TM 5-4110-234-14

TO 40R7-5-7-1

b. The indicators located inside the unit are:

(1) Moisture indicating refrigerant sight glass. This indicator is located inside of the left side access door. It

indicates the condition of the refrigerant. The moisture sensitive center "bulls eye" will have blue color when in good dry

condition. It will change to pink when moisture (water) is present in the refrigerant system indicating possible problems.

The actual refrigerant is also visible through this glass port. After 15 minutes of operation the refrigerant observed through

this port should be clear and free of bubbles. If refrigerant has a milky appearance or bubbles are present a problem is

indicated.

Figure 2-3. Refrigerant Sight Glass

(2) Compressor oil level sight glass. The compressor oil level should be observed with the compressor running. If

the oil level in the sight glass is less than one-eighth (1/8) up from the bottom of the glass, this indicates a low oil level. If

the oil level is up more than one-half (1/2) from the bottom, this indicates a high oil level. Therefore, the oil level should be

1/8 to 1/2 up the sight glass when the compressor is running.

Figure 2-4. Compressor Oil Level Sight Glass

2-4