High And Low Pressure Switch Errors; Outdoor Control 7-Segment Display Alert Codes - High And Low Pressure Switches - Lennox XP25-024-230-01 Installation And Service Procedure

High and Low Pressure Switch Errors

Table 12. Outdoor Control 7-Segment Display Alert Codes - High and Low Pressure Switches
NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).
Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert
codes are also displayed on the iComfort Wi-Fi
Alert
Priority
Codes
The outdoor unit low pressure
E 410 Moderate
switch has tripped.
The low pressure switch has tripped
E 411 Critical 5 times within one hour. As a result,
the outdoor unit is locked out
The outdoor unit high pressure
E 412 Moderate
switch has opened.
The high pressure switch has
opened 5 times within one hour. As
E 413 Critical
a result, the outdoor unit is locked
out
®
thermostat.
Alarm Description
.
.
Possible Causes and Clearing Alarm
Unit pressure is below the lower limit. The system is shutdown. The low pressure switch
opens at 25PSIG and closes at 40PSIG. Confirm that the system is properly charged
with refrigerant. Check TXV, indoor unit blower motor, dirty filters or clogged refrigerant
filter. Confirm that the evaporator coil is clean. The alarm clears after the pressure
switch opens or after a power reset.
Low pressure switch error count reached 5 strikes. The low pressure switch opens at
40PSIG and resets at 90PSIG. Confirm that the system is properly charged with refri­
gerant. Check for clogged TXV, blockage to indoor unit blower motor, dirty filters or
clogged refrigerant filter. Confirm that the evaporator coil is clean. The alarm clears
after a power reset.
Unit pressure is above the upper limit. System is shut down. The high pressure switch
opens at 590PSIG and closes at 418PSIG. Confirm that the system is properly charged
with refrigerant. Check for clogged TXV, blockage to indoor unit blower motor, clogged
refrigerant filter. Confirm that the outdoor unit is clean. The alarm clears after the pres­
sure switch closes or a power reset.
For heating, indoor CFM may be set too low. For zoning system, zone CFM may be set
too low.
Unit pressure is above the upper limit. System is shut down. The high pressure switch
opens at 590PSIG and closes at 418PSIG. Confirm that the system is properly charged
with refrigerant. Check for clogged TXV, blockage to indoor unit blower motor, clogged
refrigerant filter. Confirm that the outdoor unit is clean. The alarm clears after the pres­
sure switch closes or a power reset.
For heating, indoor CFM may be set too low. For zoning system, zone CFM may be set
too low.
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