Thermo King 098916, Руководство по обслуживанию

Страница: 134 / 196

Refrigeration Maintenance
133
Checking Refrigerant Charge
The refrigerant charge should be checked during
pretrip and routine maintenance inspections. A
low charge of refrigerant will cause the container
temperature to rise due to the lack of liquid
refrigerant at the expansion valve even though the
unit is operating in a cooling mode. All
MAGNUM units are charged with 4.0 kg (8.0 lbs)
R-404A refrigerant at the factory. The refrigerant
charge can be checked by inspecting the receiver
tank sight glass.
1. Inspect the receiver tank sight glass with the
unit operating in cool or modulation cool. If
the ball floats in the bottom receiver tank sight
glass when the compressor is engaged, the
R-404A charge level is correct.
2. If the ball is not floating in the sight glass, the
unit may be low on R-404A charge. Adjust the
controller setpoint to operate the unit on cool.
Operate the unit on cool for 5 minutes. If the
ball floats in the receiver tank sight glass, the
R-404A charge level is correct.
3. If the ball in the receiver tank sight glass does
not float after operating the unit on cool for 5
minutes, the unit is low on R-404A charge.
With the unit operating on cool, add liquid
R-404A charge. With the unit operating in
cool, add liquid R-404A until the ball in the
receiver tank sight glass floats in the sight
glass.
NOTE: Inspect the unit for refrigerant leaks
with a reliable leak detector if the unit is low
on R-404A charge.
Receiver Tank Sight Glass
The receiver tank contains a sight glass which has
three small balls that indicate the level of
refrigerant in the tank for checking the refrigerant
charge. A moisture indicator in the sight glass
changes color to indicate the level of moisture in
the system. Check the color of the indicator
against the color decal in the sight glass. The dry
eye in the sight glass is light green when the
system is dry and yellow when the system is wet
(contains excessive moisture).
CAUTION: When adjusting the controller
setpoint to check refrigerant charge, be
sure to return controller to the setpoint
indicated on the shipping manifest.
1. Moisture Indicator:
Light Green = Dry
Yellow = Wet
2.
Outer ring is color coded. Compare to
indicator.
Figure 84: Receiver Tank Sight Glass
AXA0371