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TM 5-4120-361-14
repaired. An inoperative compressor is usually due to a
(7) Triple evacuate system and charge with
mechanical failure or motor burnout. If the compressor is
refrigerant R22.
mechanically frozen or sustains a motor burnout, it must be
replaced. A compressor failure generates high temperature
(8) Start air conditioner (figure 2-5) and operate
causing a breakdown of oil, refrigerant and motor insula-
unit for 24 hours.
tion, with the resulting formation of acid, moisture, and
sludge. These products are extremely corrosive and must be
(9) Discharge system and purge with nitrogen
flushed from the system or repeated burnouts will occur.
(figure 6-1).
b. Procedure.
(10) Install new dehydrator (figure 5-7).
(1) Discharge system and purge with nitrogen
NOTE
(figure 6-1).
Whenever available, use recycled refrigerant for
(2) Remove defective motor-compressor
charging the refrigeration system.
(figure 5-2).
(11) Evacuate system and recharge with refriger-
(3) Remove dehydrator (figure 5-7).
ant (figure 6-2).
(4) With compressor out of system, purge all
(12) Operate air conditioner.
lines with dry nitrogen.
6-6. Evaporator and Condenser Coils.
(5) Install a new compressor (figure 5-2) con-
taining a full and proper oil charge.
a. Inspection. Inspect coils for damaged tubing and
bent fins. Inspect threaded holes for damaged or stripped
(6) Install new dehydrator (figure 5-7). In step
threads.
(10) this dehydrator will again be replaced.
STEP 4.
STEP 5.
POSITION REFRIGERANT DRUM UPRIGHT ON SCALE
WITH LINES CONNECTED FOR GAS CHARGING. IF THE
WEIGHT OF REFRIGERANT TO FULLY CHARGE THE SYS-
TEM IS KNOWN, OPERATE AIR CONDITIONER WITH CON-
TROLS SET FOR MAXIMUM COOLING. OPEN REFRIGER-
ANT DRUM VALVE, LOW PRESSURE CHARGING VALVE,
AND LOW SIDE MANIFOLD VALVE. CONTINUE OPERA-
TION UNTIL THE SYSTEM IS FULLY CHARGED, THEN
CLOSE VALVES. STOP AIR CONDITIONER OPERATION
AND DISCONNECT CHARGING LINES.
TO ADD REFRIGERANT TO SYSTEM WITH LOW CHARGE
AS INDICATED BY BUBBLES IN LIQUID SIGHT INDICA-
TOR:
WITH REFRIGERANT DRUM UPRIGHT, CONNECT LINES
FOR GAS CHARGING THROUGH LOW SIDE MANIFOLD
VALVE. PURGE CHARGING LINES BY LOOSELY CON-
NECTING LINE AT DRUM VALVE AND SLIGHTLY OPEN-
ING AIR CONDITIONER CHARGING VALVES. TIGHTEN
LINE AT DRUM VALVE. OPERATE AIR CONDITIONER
WITH CONTROLS SET FOR MAXIMUM COOLING. OPEN
REFRIGERANT DRUM VALVE, LOW SIDE MANIFOLD
VALVE, AND LOW PRESSURE CHARGING VALVE ON AIR
CONDITIONER. CONTINUE OPERATION UNTIL BUBBLES
NO LONGER APPEAR IN SIGHT INDICATOR. THEN CLOSE
LOW PRESSURE CHARGING VALVE ON AIR CONDI-
TIONER. REPEAT CHARGING IF BUBBLES REAPPEAR IN
SIGHT INDICATOR. WHEN BUBBLES DO NOT REAPPEAR
AFTER 15 MINUTES OF OPERATION, THE SYSTEM IS
FULLY CHARGED. CLOSE CHARGING VALVES AND DIS-
CONNECT LINES.
Figure 6-2. Charging refrigerant system (Sheet 2 of 2)
6-5
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