Refrigerant Pressure Check - TM-5-4120-393-140239

TM 5-4120-393-14

5-15. Refrigerant Pressure Check

This task covers:

a. Service

Initial setup.

Tools:

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

Rubber gloves NSN 8415-00-266-8677

Safety goggles NSN 4240-00-052-3776

Personnel: 1

General Safety Instructions:

WARNING

Death or serious injury may result if personnel fail to observe safety precautions.

Use great care to avoid contact with liquid refrigerant or refrigerant gas being

discharged under pressure. Sudden and irreversible tissue damage can result

from freezing. Wear thermal protective gloves and a face protector or goggles in

any situation where skin-eye-contact is possible.

Prevent contact of refrigerant gas with flame or hot surfaces. Heat causes the

refrigerant to break down and form carbonyl chloride (phosgene), a highly

poisonous and corrosive gas.

SERVICE

Except in cases where it is obvious that the refrigerant charge has been lost, the first step in troubleshooting problems

in the refrigeration system should be to check discharge and suction pressures under operating conditions.

Check pressures as follows:

Turn the mode selector switch to OFF.

Remove valve stem and hose connection protective caps from service valves. Take care that valve stem caps

are not lost.

Connect individual pressure gages, or a refrigeration charging manifold and hoses to the high (discharge) and low

(suction) service valves.

CAUTION

Take care that only a very small amount of refrigerant is allowed to escape during

hose purging.

Loosen hose connections at gages or charging manifold.

Open high (discharge) pressure service valve slightly to purge air from hose. Tighten high pressure hose

connection at gage fitting as soon as a hissing sound is heard. Repeat procedure with low (suction) pressure

service valve.

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