Charging Station Method; Depressurizing - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
b. Connect the manifold gauge set to the Schrader valves on the fire wall. (Refer to Figure 14-36.)
c. The high and low manifold hand valves should be in the closed position. (Refer to Figure 14-33.)
d. Connect the center manifold hose to the inlet of the vacuum pump.
NOTE
Make sure the exhaust port on the vacuum pump is open to avoid
damage to the vacuum pump.
e. Operate the vacuum pump and open the low side manifold hand valve. Observe the compound.
low pressure gauge needle, it should show a slight vacuum.
f. Continue to operate the vacuum pump until 26 to 28 inches of vacuum is attained on the low
pressure gauge, then extend the operation for another 25 minutes.
g. If the system cannot maintain 26 to 28 inches of vacuum, close both manifold hand valves and
observe the compound gauge.
h. Should the compound gauge show a loss of vacuum, there is a leak in the system which must be
repaired before continuing with evacuation.
i. If no leaks are evident, reopen both manifold hand valves and continue the evacuation for
another 30 minutes.
j. Close both manifold hand valves, stop vacuum pump and disconnect center manifold hose from
the vacuum pump.
k. Proceed to charge the system in accordance with paragraph 14-100.
NOTE
The system should be charged as soon as it has been evacuated.
14-100. CHARGING THE SYSTEM. When the system is completely evacuated in accordance with
instructions given in paragraph 14-99. one of the following procedures should be used to charge the system.
14-101. CHARGING STATION METHOD.
NOTE
Applies to Kent Moor J8393-02 or similar charging station. Use
Refrigerant 12. (Refer to Figure 14-37.)
a. DEPRESSURIZING (required only if system contains refrigerant).
1. Close all valves on charging station.
2. Connect red high-pressure charging line to high pressure Schrader valve at the fire wall fitting of
the right nacelle. (Refer to Figures 14-38 and 14-42.)
3. Open valve 2 (high pressure control) on charging station one turn.
4. Hold end of blue low pressure charging line in a shop rag and slowly open valve 1 (low
pressure control) on charging station allowing refrigerant to exhaust from system into shop rag.
Reissued: 9/23/80
ACCESSORIES AND UTILITIES
4 H1