Figure 4-2. Refrigerant 22 pressure-temperature chart.

temperature is low, Install cap on side of valve

when adjustment is completed. Remove gage and

thermometer,

Figure 4-2. Refrigerant 22 pressure-temperature chart.

4-63. Pressure Relief Valve

refrigerant system. When the sight glass indicates

t h a t moisture is present in the system (para 4-57), it

T h e pressure relief valve is a safety device used to

should be reported to DS Maintenance for

relieve refrigerant pressure if it attempts to go

correction.

higher than the system is designed to withstand.

Proper relief pressure is 540 PSIG. The only in-

4-66. Evaporator Coil

s p e c t i o n required for this device is to insure that the

a. Inspection and Test. Inspection and test of

v a l v e or its connection to the tubing is not leaking

t h e evaporator coil consists of examination for bent

fins and accumulation of external contamination

4-64. Fluid Pressure Regulator

and test for refrigerant leaks (para 4-55).

b . Service. Scrub the external portion of the coil

The pressure regulator valve is incorporated in the

with a stiff bristle brush or soft bristle wire brush to

refrigerant system to regulate pressure on the

remove scale and corrosion. Take care not to

suction side of the system and maintain it a

damage the fins. Use compressed air to blow out

minimum of 30 PSIG at all times the air con-

l o o s e material. Wipe the coil with a cloth dampened

d i t i o n e r is operating on the cooling cycle. To check

w i t h dry cleaning solvent per Federal Specification

t h e valve, install a gage on the suction service valve

P-S-661. Bent fins may be straightened with a fin

a n d increase the control thermostat setting until the

c o m b (12 fins per inch spacing) or with needle nose

l i q u i d line solenoid valve closes. This will lower the

pliers.

suction pressure. The fluid pressure regulator is

factory set and sealed at 58 PSIG.

4-67. Condenser Coil

4-65. Dehydrator

a. Inspection and Test. Inspection and test of

t h e condenser coil consists of examination for bent

T h e dehydrator is a filter and moisture drier for the