Compressor Oil Condition

TM 10-4110-262-13&P

0029 00

Compressor Oil Condition

1. Check the compressor oil condition by observing its color during each major service or system repair.

2. Test a sample of compressor oil for acid contamination. If acid is present, the system must be flushed

and replenished with clean oil.

NOTE

The acid test kit must be compatible with Polyol Ester compressor oil and R404A.

Clear Oil Appearance of good oil.

Black OilCarbonization from operating a unit with air and moisture in the system.

Brown Oil

Results from moisture in the system causing an acid condition and subsequent copper plating.

Gray/Metallic

Caused by wear metal from pistons, bearings, cylinders, etc.

ADJUST

Expansion Valve Test / Superheat Adjustment

NOTE

Before beginning this procedure, perform the compressor functionality test and

check the refrigerant charge level. Correct any deficiencies observed.

1. Install an accurate compound gauge at the compressor suction access valve.

2. Install an accurate thermometer sensor beside the expansion valve feeler bulb. Secure and insulate the

temperature sensor.

3. Defrost the evaporator and stabilize the box temperature near 35 F (2 C).

4. Cover the condenser inlet as needed to maintain a discharge pressure of 320 340 psi.

5. Read the suction pressure and box temperature simultaneously. Record your readings every two

minutes for at least ten minutes (five or more readings). Calculate the average value of each reading.

Convert the suction line pressure to temperature using the chart presented in WP 0002 00.

6. Calculate the superheat value according to the formula:

Superheat = Suction Line Temperature Suction Temperature.

Superheat should be between 10 F and 12 F at a box temperature of 35 F.

0029 00-3