RJ150-30 / Operations and Maintenance Manual
Mobile Aircraft Air Conditioner
Trailer Mounted, Cool Mode Only
______________________________________________________________________________
JANUARY 20, 2004
SECTION 2 - 1
PAGE 17
F. Charging Refrigerant:
The refrigerant system should always be adequately charged if the air
conditioning unit is to provide the proper amount of cooling. A shortage of
refrigerant will be evidenced by a loss of cooling effect, a low suction
pressure, and a low head pressure. The necessity to add refrigerant is not
considered routine maintenance. The loss of any portion of the refrigerant
charge indicates a refrigerant leak and thereby a need for service.
A liquid sight glass is located in the refrigerant piping between the filter-drier
and the expansion valve. (See Figure 3) When the refrigerant charge is low,
bubbles will be evident in the liquid refrigerant flowing through the sight glass.
Add refrigerant to the point at which the bubbles are eliminated or only an
occasional bubble is noticed.
WARNING
DO NOT OVERCHARGE THE REFRIGERANT SYSTEM. OVERCHARGING THE
SYSTEM CAN DAMAGE THE UNIT.
Refrigerant Charge for Model RJ150: (Refer to Section 1-3)
•
Units with R-22 or R-407C Refrigerant: 30 lbs (13.6 kg)
•
Units with R-134a Refrigerant: 32 lbs (14.5 kg)
If the system has lost its charge completely, it should be evacuated prior to
recharging. The following procedure is to be used when adding to or replacing
the refrigerant charge.
(1) Using a platform scale, weigh the refrigerant cylinder and its contents.
Record this weight for later reference.
(2) Using a copper connecting tube or other appropriate charging hose,
loosely connect the outlet of the cylinder to the charging port located on
the suction line. (See Figure 3)
(3) Position the cylinder so that the top is at a higher level than the bottom to
ensure release of the refrigerant in the gaseous state.
(4) Slightly open the valve on the refrigerant cylinder.
(5) Purge the charging line and tighten the connection. A mixture of ethylene
and glycerine, or a commercial seal lock should be used to seal the
connection.
(6) Check the tubing connections between the cylinder and the charging
valve for leaks.
(7) Open the valve on the refrigerant cylinder approximately halfway.
(8) Open the charging valve.
(9) Close the refrigerant valve on the liquid line leading from the receiver to
the expansion valve. Be sure the compressor suction (low-pressure) and
discharge (high-pressure) Rotolock valves are open.
