Thermo King KD-II SR, Manual

Page: 115 / 182

Refrigeration Maintenance (Rev. 04/03)
101
4. As the head pressure is rising, check the receiver tank
sight glass. The ball should be floating. If there is no
indication of refrigerant in the receiver tank sight glass,
the unit is low on refrigerant.
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
evidence 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.
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 below 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.
NOTE: Use refrigeration compressor oil ONLY. R-134a
and R-404A systems use a special Ester oil TK No.
203-413.
To add oil to the compressor, pump down compressor, see
“Compressor Pump Down and Checkout.”
1 Add Compressor Oil Here
2 Oil Level Sight Glass
X214 Compressor