TM 9-4120-408-14
5-10. CONDENSER PRESSURE SWITCH MAINTENANCE. (Continued)
NOTE
Setting for high pressure fan cut in switch S4 is 190 3 psi.
(2) Ensure low pressure fan switch S3 (2) is set to 160 3 psi.
(3) Remove spring clip (3) and cover (4) and check wire connections to low pressure fan switch S3 (2).
Tighten loose connections.
b. Test.
NOTE
Apply pressure as required using dry nitrogen.
(1) Install pressure gauge of manifold to gauge port (5) of condenser assembly (6).
(2) Remove spring clip (3) and cover (4) from pressure switch (2).
NOTE
Resistance measurements on high pressure fan cut in switch S4 will be as follows:
At pressures below 190 3psi resistance between contacts 1 and 2 will be 0 and resistance
between contacts 2 and 3 will be infinite.
At pressures of 190 3psi or above resistance between contacts 1 and 2 will be infinite and
resistance between contacts 2 and 3 will be 0.
Resistance measurements on high pressure cut out switch S6 (2) will be as follows:
At pressures up to 275 9psi resistance between contacts 1 and 2 will be 0 and resistance
between contacts 2 and 3 will be infinite.
At pressures above 275 9 psi resistance between contacts 1 and 2 will be infinite and
resistance between contacts 2 and 3 will be 0.
(3) Resistance measurements on low pressure fan switch S3 (2) will be as follows:
At pressures of 160 3psi and below resistance between contacts 1 and 2 will be infinite and resistance
between contacts 2 and 3 will be 0.
At pressures above 160 3psi resistance between contacts 1 and 2 will be 0 and resistance between
contacts 2 and 3 will be infinite.
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