Unit Control Panel
The display shown below has four (4) digits. The left two digits indicate the error code (1 to 24), The On/Off icons above
these two digits indicate the currents state of the error code. The right two digits show the history count (up to 99) of the
associated error code. The display contains a maintenance icon (wrench) that will illuminate to indicate when the unit
needs maintenance.
Code Problem Action
1Front Panel Button Stuck For More Than 20 Seconds Continue to Monitor for “OPEN” (Unstuck) switch. Do not process switch input.
2 Unit stops, open all relays until voltage is back within specs then resume
3Indoor Temperature Sensor is Open or Shorted Unit defaults to 75°F in COOLING or 68°F in HEATING and will continue to
4Indoor Coil Temperature Sensor is Open or Shorted The unit’s control board defaults 40°F. It will override the sensor and the unit will
continue to operate.
5Outdoor Coil Temperature Sensor is Open or Shorted The unit defualts to 20°F, overriding the sensor. The unit will continue to operate.
Using Elec Heat if available for HEATING. If not available, it will use HEAT PUMP
if the outdoor temperature allows.
6Outdoor Coil > (greater than) 175°F The unit will shut down for 5 minutes. Resume operation for 3 minutes. If test fails
3 times, the severity is increased and the unit operation is locked out.
7Indoor Coil < (less than) 30°F for 2 consecutive
The compressor will turn off and the High Fan speed will run. When coil temp
reaches 45°F the unit will resume operation after lockout time.
8Unit Cycles > (greater than) 9 Times per hour The unit will continue to operate and be monitored.
9Unit Cycles < (less than) 3 Times per Hour The unit will continue to operate and be monitored.
10 Room Freeze Protection Only use if Electric Heat is available. Run High Speed and Electric Heat until room
temp reaches 46°F. The unit will display “FRZ” during operation. Logged Only.
11 WallStat Problem or Connection Issue The unit will not operate.
12 Not Applicable Not Applicable
13 High Pressure LImit Switch is Open If unit is cooling or heat pump is on, shut down compressor. Run high fan until
switch closes, then resume operation. The third occurance in 1 hour locks unit out.
Applicable to 24K unit only.
14 Not Applicable Not Applicable
15 Heat Pump Error If indoor coil temperature is less than ambient temperature for 3 minutes the unit
will use electric heat to satisfy the heating demand.
16 Temperature Beyond Operating Limits Occurs if the ambient temperature range falls below 0°F or greater than 130°F.
The error code will remain on until the temperature reaches the operating range
and then the unit will return to normal operation.
17  The compressor must be enabled and have at least 2 fan speeds
18 Not Applicable Not Applicable
19 Not Applicable Not Applicable
20 Not Applicable Not Applicable
21 Not Applicable Not Applicable
22 Outdoor Coil Temperature < 30°F for 2 consecutive
Unit will use electric heat to satisfy heating demands until the tempearture equals
or exceeds 45°F. Applicable for Heat Pump models only.
23 Frost Protection Unit will run active defrost for a minimum of 6 minutes when Heat Pump run time is
greater than 60 minutes and outdoor coil temperature is 26°F or less.
24 Not Applicable Not Applicable
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