TM 9-4120-388-14
5-25. PRESSURE REGULATING VALVE.
b. Removal
This task covers:
a. Adjustment/Test
c. Installation
INITIAL SETUP:
Equipment Condition
Lower front panel removed (4-28).
Side access cover removed (4-22).
a.
Adjustment/Test.
(1) Valves are factory set to start opening when suction pressure decreases to 58 psig. Do not adjust unless
you are sure adjustment is necessary.
(2) Perform a refrigeration pressure check on unit in accordance with paragraph 5-13. Leave the gages or
service manifold attached.
(3) Set TEMPerature control thermostat knob fully INCREASE (clockwise), start air conditioner in COOL mode
and observe pressure gages. Suction pressure should drop to 582 psi (40 1.4 kg/mm2) shortly after
(4) If unit fails above test, the pressure regulating valve must be adjusted.
(a) Turn unit OFF.
(b) Loosen four captive panel fastener screws in junction box mounting flange.
Take care that wire harnesses, capillary line, and circuit breaker reset linkage are
not damaged.
(c) Carefully pull junction box out far enough to gain access to button plug in end of pressure regulating valve.