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TM 9-4120-389-14
5-20. PRESSURE SNITCHES (S4 AND S5)
Preliminary procedure: Remove top cover (See para. 4-14).
a.
Test
(1)
Press and release reset button to be sure that switch is
not tripped.
(2)
Tag and disconnect leads on pressure switch.
(3)
Using multimeter set on lowest OHMS scale, check for continuity between terminals 1 and 2
on pressure switch (S4 or S5). Be sure reset is pressed in.
(4)
If there is no continuity, replace pressure switch.
b.
Removal
WARNING
All refrigerant -22 must be discharged from system before attempting to remove
pressure switches (S4 and S5).
(1)
Tag and remove jumper lead between S4 and S5.
(2)
Discharge the refrigeration system (See para. 5-3).
(3)
Restrain tube and fitting.
(4)
Loosen flare nut.
(5)
Remove screw and lock nut from clamp that secures capillary tubing.
(6)
Remove clamp.
(7)
Remove two screws and lockwashers from switch. (S4 or S5).
(8)
Remove pressure switch (S4 or S5).
c.
Installation (S4 or S5)
(1)
Coil capillary tube of replacement pressure switch.
(2)
Install pressure switch on bracket using two screws and lockwashers.
(3)
Restrain tube and fitting.
(4)
Tighten flare nut on fitting.
5-50
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