| Tweet |
Custom Search
|
|
|
||
 TM 55-1905-219-14-11
5-144. REFRIGERATOR/FREEZER - MAINTENANCE INSTRUCTIONS
(Continued).
LOCATION
ITEM
ACTION
REMARKS
SERVICE (Cont)
d.
How to discharge excess refrigerant.
(1)
Too much or too little refrigerant will result in improper operation.
(2)
System with too much refrigerant is similar to one with air in system.
(3)
If the operating head pressure is too high, stop the machine, and allow the unit to cool to room
temperature. If the off head pressure is still higher than the corresponding room temperature, air is in the system. If the
off pressure drops to normal, there is too much refrigerant. This excess liquid reaches the condenser area and overloads
the machine causing it to run excessively. The overload protection may trip. The condenser will be hotter than normal
near the top and cooler than normal near the bottom. In any case, refrigerant will not be satisfactory and the charge
must be reduced to the correct amount by discharging excess refrigerant.
(4)
Excess refrigerant is released through the high-side service valve. The high pressure gauge must be
attached to the high-side valve in the regular way to observe the drop in pressure as the refrigerant is removed. The
gauge connection of the high-side cylinder valve may be opened a little, two or three times in succession until the
pressure comes down to a normal corresponding value of the condensating gas pressure and the room temperature in
which the cooler is operating.
(5)
Open the discharge service valve to release some of the refrigerant. Do not let too much refrigerant
out at a time, as this may discharge more refrigerant than necessary and result in improper operation of the cooler.
e.
Testing for leaks.
(1)
If a leak is suspected in the system, check entire system including all tubing connections, valves,
receiver, condenser, evaporator and compressor.
(2)
Sometimes oil may be visible where leaks occur. The method for testing for leaks is two-fold,
depending on whether or not leak occurs on the high-side or on the low-side.
5-1462
|
||
|
||
