Piper Aircraft Corporation Malibu Mirage PA-46-350P, Airplane Maintenance Manual

Page: 337 / 1956

PAGE 19
Feb 28/07 2E11
21-50-00
PIPER AIRCRAFT, INC.
PA-46-350P, MALIBU MIRAGE
MAINTENANCE MANUAL
13 When evacuation sequence has continued for the programmed length of time and
the panel display reads CPL (complete), close both the low side valve (1) and the
high side (2) valves.
14 Perform charging procedure immediately. (See Charging the System, below.)
(3) Leak Detection (See Figures 3 and 4.)
(a) Using Nitrogen
1 Prepare aircraft so as to provide access to all air conditioning components and fitting
connections being leak checked.
2 Ensure that aircraft and ground power are OFF or disconnected.
3 Close all valves on the charging station.
4 Remove the protective caps from the high and low side service ports on the
evaporator unit.
5 Connect the blue and red hoses to the service ports as shown in Figure 5.
6 Slowly pressurize the system to 200 psig max. with nitrogen and turn off the nitrogen
source. Ensure gages used have a 0-400 psig range.
7 Monitor pressure on the charging station gauge for 20 minutes. A leak free system
will maintain the 200 psig pressure for 20 minutes.
8 If there is no pressure drop for 20 minutes, slowly release nitrogen pressure and
disconnect the nitrogen source from the evaporator assembly. Re-install the pressure
switch per drawing requirements. The leak check procedure is completed.
9 If there is a pressure drop, find leak(s) by applying a soap solution to all connections.
10 Rework system as required to stop leaks and repeat Leak Check Procedure.
(b) Using HFC-134a
(PIR-PPS50003-4, Rev. A.)
A leak may be located while a charging stand is hooked up to the system as follows:
1 Ensure that there is at least one pound of refrigerant in the charging cylinder.
2 Open the high pressure control valve and the refrigerant control valve on the
charging stand. Allow one pound of refrigerant to enter the system.
3 Close the high pressure control valve and the refrigerant control valve.
CAUTION: USE A THICK SOLUTION OF SOAP AND WATER TO CHECK FOR
LEAKS INSTEAD OF THE PROPANE LEAK DETECTOR THAT IS
PROVIDED WITH SOME BRANDS OF CHARGING STANDS.
4 Locate leak(s) using an electronic leak detector designed to detect HFC134a
refrigerant. Or, use soap and water in a thick solution.
5 Tighten/re-tighten fittings as necessary to stop leak(s). If leaks are due to damaged
or worn components, proceed with refrigerant recovery/system discharge, perform
repairs or component replacement and repeat leak detection procedure.
6 Discharge the system.
NOTE: The term “Discharge,” as used throughout this section, in no sense implies
or suggests discharging refrigerant to atmosphere. In all cases when
discharging, an environmentally approved refrigerant recovery station is to
be used.
7 Evacuate the system.
8 Immediately recharge the system as described in Charging the System, below.