|
| |
TM 9-4120-389-14
a.
Inspection
WARNING
All refrigerant -22 must be discharged from system before attempting to remove
liquid quench expansion valve.
(1)
Inspect for evidence of leaks, kinked, or otherwise damaged capillary line, and loose or
missing mounting hardware.
(2)
Check thermal bulb to see that it is securely sealed on clamps.
(3)
If a leak is suspected or indicated, test per para. 5-6.
b.
Test
(1)
Perform a refrigerant pressure check on unit in accordance with paragraph 5-9. Leave gages
or service manifold attached.
(2)
Unwrap insulation tubing from compressor suction line so that sensing bulb and an adjacent
section of the suction line is exposed.
(3) Attach an accurate thermometer to an exposed surface of the suction line adjacent to the
sensing bulb; use a small gob of thermal mastic (Item 17 Appendix E) to improve conductivity.
(4) Check that gage connection to low (suction) side is open. Note pressure indicated on gage and
temperature indicated on thermometer.
(5) Set the Temperature control thermostat knob to full WARMER (clockwise). Start the air
conditioner in COOL mode. Note that suction pressure drops to 58 ± 2 psig (4.0 ± 0.2 kg/cm2). Allow
compressor to run for at least 20 minutes. If pressure is not within above limits, test operation hot gas bypass
valve (para. 5-18) before proceeding with quench valve test.
NOTE
Except in a very hot climate, with room temperature above 90 deg. F (32.2 deg.
C), the refrigeration system will be in a bypass cycle with a maximum volume of
hot discharge vapor being recirculated back to suction side of compressor through
pressure regulator valve and quench valve.
(6)
Observe that temperature indicated remains stable for a minimum of two minutes, then find
saturation temperature for pressure indicated on gage, using table 5-1. For example: The saturation
temperature for a refrigerant pressure of 69 psig (4.85 kg/cm2) is 40.deg. F (4.4 deg. C).
5-42
|
