HVAC Controls & Thermostats Error Codes

Programming mode active — the controller is in programming or configuration mode.

Serious external alarm — a critical external alarm condition has been detected via the digital input.

Anti short cycle delay enabled — the compressor is in delay before restart.

Compressor enabled — the compressor relay output is active.

Door Open alarm — the door switch indicates the door is open.

Dripping in progress — the drip time after defrost is active.

Defrost in progress — the defrost cycle is currently active.

Download mode active — controller is downloading parameters from Hot Key.

External alarm — an external alarm condition has been detected via the digital input.

Programming data ready — indicates data is being programmed to/from Hot Key.

Error during programming key operation — invalid operation or incorrect input.

Fans delay after defrost — the fan delay timer is active.

Fans output enabled — the fans relay output is active.

Maximum temperature alarm — the measured temperature has exceeded the maximum alarm threshold.

Minimum temperature alarm — the measured temperature has fallen below the minimum alarm threshold.

Indicates dripping period following defrost cycle – condensate management.

Fans remain off until delayed period after completion of a defrost cycle.

Indicates the anti-short cycle delay interval is active after a compressor shutdown.

Indicates that the unit is in programming mode; use 'SET + UP' to exit.

No parameters in Level 1 — there are no user-level parameters available.

Keyboard locked — the front panel keypad is locked.

Keyboard unlocked — the front panel keypad is now unlocked.

Room probe failure — thermostat malfunction or disconnected.

Evaporator probe failure — temperature sensor issue preventing defrost.

The system detects a serious alarm or fault condition requiring immediate attention.

Upload mode active — controller is uploading parameters to Hot Key.