Chapter 6. REPAIR INSTRUCTIONS - TM-5-4120-285-150095

CHAPTER 6

REPAIR INSTRUCTIONS

Section I. REFRIGERATION SYSTEM

remove the condenser fan and remove the hose

6-1. Servicing the Refrigerant System

from the discharge service valve. Reinstall con-

a. General. When a leak is suspected within the

senser fan and grill (para 319).

system it is necessary to make a thorough check

d. Pressure Testing and Evacuating the Sys-

to locate the leak. To gain access to the refriger-

tem.

ant components it is necessary to remove the pan-

(1) Remove the condenser fan (para 3-19).

els, grills, and covers, as well as the condenser

(2) Connect the suction line of a suitable

fan. Refer to the applicable maintenance para-

pressure manifold loosely to the suction service

graph for instructions covering the removal and

valve. Connect the center manifold line to the re-

installation of the protecting access components.

frigerant drum and the discharge pressure gage

b. Testing Procedures.

line to the discharge service valve. Make sure all

(1) Halide torch method. The Halide torch

valves and the drum and gages are closed (fig.

system is recognized as the most efficient method

6-1).

to test the refrigerant system for leaks. The

( 3 ) Open the refrigerant drum shutoff

Halide detector suction tube is passed over all

slightly to purge hose line. Tighten connection at

sweated connections, fittings, and valve connec-

suction service valve. Open suction service valve

tions. The original blue flame will turn green

and drum shutoff valve.

when a leak is detected. A large leak will turn

the flame dense blue with a reddish tip, or, put

Note. Drum must be in upright position to allow

the flame out altogether. Mark any leaks and

only gaseous element to enter system.

refer to the applicable maintenance paragraph

(4) Close the drum shutoff valve when the

for repair instructions.

discharge pressure reaches 10 psig. Close suction

(2) Soap solution method. Brush all possible

service valve and disconnect hose from refriger-

areas of leakage with a liberal soap solution. A

ant drum.

leak will cause the solution to bubble. When

(5) Loosen suction service valve connection

using this method, follow a definite pattern to in-

and connect the center manifold line to nitrogen

sure that all components are checked.

drum shutoff valve (fig, 6-2).

c. Purging the System.

(6) Tighten suction service valve connection,

(1) Remove the condenser fan (para 3-19).

open service valve and nitrogen shutoff valve.

(2) Remove the outdoor thermostat (para

Build up system until pressure reaches 150 psig.

3-31) or the alternate cover at the right of the

Close suction service valve and shutoff valve. Dis-

fan area and insert a suitable hose to the dis-

connect hose from service valve and remove pres-

charge service valve.

sure manifold.

(3) Reinstall the condenser fan and grill

(7) Test for leaks and purge system (sub-

(para 3-19).

paragraph b and c above).

(4) Start the unit and discharge the refri-

( 8 ) Remove cap from discharge service

gerant into a safe area outside.

valve. Attach a suitable vaccum pump to suction

Warning: Avoid bodily contact with the

service valve and a manometer to the discharge

refrigerant or inhaling any refrigerant gases.

service valve. Open both service valves and oper-

In case of a leak, ventilate the area immediately.

ate the vacuum pump until the manometer indi-

In case of bodily contact, seek medical aid im-

cates 2.5 mm hg. abs. (millimeters mercury abso-

mediately.

lute).

(9) Close suction valve and stop the pump.

(5) When system is completely discharged,

6-1