Pressure Regulator - TM-5-4120-393-140263

TM 5-4120-393-14

5-24. Pressure Regulator

This task covers:

a. Adjustment

c. Installation

b. Removal

Initial setup.

Tools:

Tool kit, service, refrigeration unit NSN 5180-00-596-1474

Personnel: 1

Materials:

Equipment condition:

1. Turn unit power off at power source. If there is a chance that it will be turned on, also disconnect power cable

to air conditioner.

2. Remove lower front panel. See para 4-24.

3. Remove junction box number two. See para 4-46.

General Safety Instructions:

WARNING

Disconnect input power to the air conditioner before performing any internal

maintenance. Voltages used can KILL. Shutting the unit off at the control panel

does not disconnect unit power.

ADJUSTMENT

NOTE

Valves are factory set to start opening when suction pressure decreases to 58

psig. Do not adjust unless you are sure adjustment is necessary.

Perform refrigeration pressure check on unit. See para 5-15. Leave gages or service manifold attached.

Set TEMPerature control thermostat knob fully INCREASE (clockwise), start air conditioner in COOL mode, and

observe pressure gages. Suction pressure should drop to 58 2 psi (4.0 + 0.14 kg/cm ) shortly after compressor

starts, and then remain constant.

To adjust suction pressure, remove button plug from top of pressure regulator valve and turn adjusting stem clockwise

to raise (increase) pressure, or counterclockwise to lower (decrease) pressure. If pressure is low (below 56 psi) and

cannot be raised by adjustment, pressure regulator valve must be replaced. If pressure is high (above 60 psi) and

cannot be lowered by adjustment, test operation of the quench valve (para 5-20) before replacing pressure regulator

valve.

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