Section VII. ACCESS FITTINGS

TM 5-4120-273-15

superheat does not reach the required valve when

out of the evaporator coil is satisfactory. A super-

adjusted, check for dirt or other restrictions in the

heat of 10F to 20F when measuring the super-

liquid line or expansion valve.

heat at the thermal bulb is also satisfactory. If the

Section VII. ACCESS FITTINGS

(8) Unscrew valve stem from inside access

6-13. Access Fittings

valve.

a. General. The access fittings provide access

c. Installation.

to the refrigerant system for service.

(1) Install valve stem into access valve.

b. Removal.

(2) Recharge system, reference paragraph

(1) Install front access panel, reference

(3) Install front access panel reference para-

(2) Slowly discharge the refrigerant charge

graph 3-18.

Section VIII. SIGHT GLASS

6-14. Sight Glass

6-15. Filter Drier

a. General. The sight glass indicates the refrig-

a. General The filter drier prevents the accu-

erant moisture content. When the indicator is

mulation of moisture and contaminant within

green the refrigerant is dry. A color shading into

the refrigerant system. The filter drier must be

yellow indicates that the refrigerant has become

replaced each time the system is exposed to the at-

contaminated with moisture. A shortage of refrig-

mosphere.

erant is indicated by flash gas in the sight glass.

b. Removal. Slowly discharge the refrigerant

b. Removal. Refer to figure 3-14 and remove

charge from the system (para 5-21b). Refer to

element from sight glass.

figure 3-6 and remove the filter drier.

c. Installation. Refer to figure 3-14 and install

c. Installation. Rederto figure 3-6 and install

new element.

filter drier.

6-4