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XP25
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
®
thermostat.
Alert
Codes
Priority
Alarm Description
Possible Causes and Clearing Alarm
E 410
Moderate
The outdoor unit low pressure
switch has tripped.
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.
E 411
Critical
The low pressure switch has tripped
5 times within one hour. As a result,
the outdoor unit is locked out
.
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.
E 412
Moderate
The outdoor unit high pressure
switch has opened.
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.
E 413
Critical
The high pressure switch has
opened 5 times within one hour. As
a result, the outdoor unit is locked
out
.
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.
