53
XC20
Component Testing
Component Testing Table of Contents
Verifying High Pressure and Low Pressure Switch Oper
ation 53.........................................
Compressor Operation, Checkout and Status / Error
Codes 56.......................................
Crankcase Heater, Checkout and Status /
Error Codes
59..................................
Compressor Sound Cover 60......................
Liquid Filter Drier (Heat Pumps only) 60.............
Top Cap Switch Operation, Checkout and Status / Error
Codes 61.......................................
Reactor Operations, Checkout and Status /
Error Codes 62..................................
Line Filter (Electromagnetic Compatibility Circuit - EMC)
Operations, Checkout and Status / Error Codes 63...
Outdoor Fan Operation and Checkout 64...........
Ferrites 65......................................
Outdoor Control Operation, Checkout and Status / Error
Codes 66.......................................
Unit Sensor Operations, Checkout and Status / Error
Codes 67.......................................
DC Inverter Control Operation, Checkout and Status /
Error Codes 70..................................
Emergency 24VAC Operation 75...................
Verifying High and Low Pressure Switch Operation
OPERATION :
The unit's pressure switches (LO PS - S87 and HI PS - S4) are factory-wired into the control on the LO-PS and HI-PS termin
als, respectively.
Low Pressure Switch (LO-PS) — See figure 28 for low pressure switch sequence of operation.
High Pressure Switch (HI-PS) — See figure 29 for high pressure switch sequence of operation.
Pressure Switch Event Settings
The following pressures are the auto-reset event value triggers for low and high pressure thresholds:
D High Pressure (auto-reset) - trip at 590 psig; reset at 418.
D Low Pressure (auto-reset) - trip at 40 psig; reset at 90.
CHECKOUT
Using a multimeter set to ohms with the terminals disconnected from the control board, check the resistance between the
two terminals of the pressure switch. If the resistance reading is 0 ohms, the switch is closed.
S4
HIGH
PRESSURE
SWITCH
S87
LOW
PRESSURE
SWITCH
Figure 30. Verifying High Pressure and Low Pressure Switch Operation
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