5-18. PRESSURE SWITCHES.
This task covers:
Tool kit, service, refrigeration unit
Power off at power source.
General Safety Instructions:
Disconnect input power to the unit before performing any internal maintenance.
Voltages used can kill. Shutting the unit off at the control panel does not
disconnect unit power.
(1) Disconnect wiring on the high (1, Figure 5-8) and low (2) pressure switches.
Blue leads are connected to the low pressure switch.
(2) Connect an ohmmeter to the low pressure switch.
(3) Discharge the system per para 5-5 and watch the ohmmeter. The low pressure switch should open at 35
(4) Charge the system per para 5-10 and watch the ohmmeter. The low pressure switch should reset at 60
Black leads are connected to the high pressure switch.
(5) Stop charging the system and connect the ohmmeter to the high pressure switch.
(6) Continue charging the system and watch the ohrnmeter. The high pressure switch should open at 400 psig.
(7) Discharge the system and watch the ohmmeter. The high pressure switch should reset and close at 300 psig.
(8) Replace any switch failing the test. If both switches passed the test, connect wires.
Install both front door assemblies. See para 4-17.