Component Testing; High And Low Pressure Switch Operation, Checkout And Status / Error Codes; Verifying High Pressure And Low Pressure Switch Operation - Lennox XP25-024-230-01 Installation And Service Procedure

Component Testing

Section Table of Contents
High and Low Pressure Switch Operation, Checkout and
Status / Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reversing Valve Operation, Checkout and Status / Error
Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Compressor Operation, Checkout and Status / Error
Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Compressor Sound Cover
Charge Compensator (XP25-024-230-XX and
XP25-048-230-XX only)
Discharge Muffler (Heat Pumps only)
Liquid Line Bi-Flow Filter Drier (Heat Pumps only)
Check Expansion Valve (Heat Pumps only)
Top Cap Switch Operation, Checkout and Status / Error
Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

High and Low Pressure Switch Operation, Checkout and Status / Error Codes

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
terminals, respectively.
Low Pressure Switch (LO-PS) — See figure 35 for low pressure switch sequence of operation.
High Pressure Switch (HI-PS) — See figure 36 for high pressure switch sequence of operation.
The following pressures are the auto-reset event value triggers for low and high pressure thresholds:
•
High Pressure (auto-reset) - trip at 590 psig; reset at 418.
•
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.
Figure 34. Verifying High Pressure and Low Pressure Switch Operation
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Pressure Switch Event Settings
Reactor Operations, Checkout and Status /
56 Error Codes
Line Filter (Electromagnetic Compatibility Circuit - EMC)
60
Operations, Checkout and Status / Error Codes
Outdoor Fan Operation and Checkout
62
Ferrites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
65
Outdoor Control Operation, Checkout and Status / Error
66
Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
66
Unit Sensor Operations, Checkout and Status / Error
Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. 67
Variable-Capacity Inverter Control Operation, Checkout
68
and Status / Error Codes
70 Emergency 24VAC Operation
S4
HIGH
PRESSURE
SWITCH
Page 56
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S87
LOW
PRESSURE
SWITCH
71
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74
75
76
79
84
XP25