Refrigeration Maintenance (Rev. 04/03)
69
NOTE: If the ball floats, there is sufficient refrigerant
in the unit for that load at that particular box temper-
ature. This test does not determine if the unit contains
a full charge of refrigerant.
CHECKING COMPRESSOR OIL
The compressor oil should be checked when there is evi-
dence of oil loss (oil leaks) or when components in the
refrigeration system have bee removed for service or
replacement.
To check compressor oil level with an ambient air
temperature above 50 F (10 C):
Install a gauge manifold on the compressor.
R-134a Systems—Operate the unit on Cool with a 10 psig
(69 kPa) minimum suction pressure and a 100 psig (689
kPa) minimum discharge pressure for 15 minutes or more.
R-404A Systems—Operate the unit on Cool with a 10 psig
(69 kPa) minimum suction pressure and 185 psig (1275
kPa) minimum discharge pressure for 15 minutes or more.
After the unit has maintained the above conditions for 15
minutes, observe the oil level. The oil should be 1/4 to 1/2
up in the sight glass.
CAUTION: Oil is under pressure. See instructions for
adding oil.
X426 Compressor
To check compressor oil level with an ambient air
temperature below 50 F (10 C):
Run the unit through a complete DEFROST CYCLE. After
completing the defrost cycle, run the unit on COOLING for
ten minutes. Observe the oil level. The oil should be 1/4 to
1/2 up in the sight glass.
If the evaporator temperature is above 32 F(0 C), it will be
necessary to force defrost. To force defrost, use a jumper
wire and jump the number 12 wire at the defrost relay to
ground. Then push the manual defrost switch. Allow evapo-
rator temperature to rise to approximately 45 F (7.2 C).
Remove the jumper wire from the defrost relay.
If the box is empty, you can run the unit on the heat cycle
instead of the defrost cycle.
To Next Page
Loading...
