Danfoss ERC 21X Alarm and Display Codes (ERC 211, 213, 214)
Error, alarm and light codes explained
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Updated October 14, 2026
Quick answer
Danfoss ERC 21X controllers flash an alarm code in turn with the cabinet temperature. A01 means the air temperature is too high, A02 too low, A04 the door has been open too long, and A61 or A80 a condenser that is too hot. E29, E27 and E30 are failed air, evaporator and condenser sensors. A80 condenser block is the one alarm that needs a manual reset.
Which controllers this page covers
The Danfoss ERC 211, ERC 213 and ERC 214 are compact refrigeration controllers that equipment makers build into self-contained commercial refrigeration units, such as coolers and display cabinets, driving compressors up to about 2 hp directly. This page uses the Danfoss ERC 21X User Guide (document BC194286421698en-001002, 2024.01).
The same codes may appear on equipment carrying another brand's name, because the controller is fitted at the factory. Check the controller face or the data label for the Danfoss name and model.
ERC 21X alarm codes
In an alarm, the display alternates between the air temperature and the code, and shows the alarm bell.
| Code | Alarm | Meaning (per Danfoss) | Owner check |
|---|---|---|---|
| A01 | High temperature | Air temperature in the cabinet is too high | Door closed and sealing; no warm product just loaded; condenser clean |
| A02 | Low temperature | Air temperature in the cabinet is too low | Setpoint not changed by mistake; product not freezing |
| A04 | Door alarm | Door has been open for too long | Close the door; check it is not propped or blocked |
| A15 | DI alarm | External alarm from a digital input | Depends on what the installer wired to the input |
| A45 | Standby | Control stopped by the r12 main switch | Controller was set to OFF; set r12 back to ON |
| A61 | Condenser alarm | Condenser temperature too high; check airflow | Clean the condenser; clear anything blocking the grille |
| A80 | Condenser block | Condenser temperature too high; manual reset required | Clean condenser, then reset (below) |
| A99 | High voltage | Supply voltage too high (compressor protection) | Electrician to check the circuit |
| AA1 | Low voltage | Supply voltage too low (compressor protection) | Not on an extension cord or overloaded circuit |
| E27 | Defrost sensor error | Evaporator (S5) sensor defective or disconnected | Technician |
| E29 | Air sensor error | Air temperature sensor defective or disconnected | Technician |
| E30 | Condenser sensor error | Condenser (Sc) sensor defective or disconnected | Technician |
Display codes that are not faults
| Display | Meaning |
|---|---|
| -d- | Defrost in progress |
| Pud | Pull-down cycle started |
| Err | Temperature cannot be shown because of a sensor error |
| LoC / UnL | Keypad locked / unlocked (hold up and down 3 seconds to unlock) |
| OFF / On | Control stopped or started with the r12 main switch |
| Fac | Controller reset to factory settings |
A unit showing -d- during a normal defrost is working as designed. Wait for defrost to finish before deciding the unit is warm.
Condenser alarms A61 and A80
Both mean the condenser is running too hot, which usually means it cannot get rid of heat: a coil clogged with dust or kitchen grease, a blocked grille, a failed condenser fan, or a unit squeezed into a hot corner. A61 warns. A80 stops the compressor to protect it and stays locked until reset.
Danfoss says to reset A80 by setting the r12 main switch OFF and then ON again, or by powering the controller down. Clean the condenser first. Resetting without fixing the airflow brings A80 straight back.
Do not factory-reset to clear an alarm
The ERC can be returned to factory settings ("Fac") by holding the arrow buttons while restoring power. That wipes the settings the equipment maker loaded for your unit, which may differ from Danfoss defaults. Leave factory resets to a technician who knows the right parameters.
When to call a technician
Call a technician for any E-code, for A80 that returns after the condenser is cleaned, for A01 that persists with the door closed, and for repeated voltage alarms (an electrician for the circuit).
Open 7 days, 8 AM to 5 PM, with emergency service until 9 PM. CA Lic. #776244.
Frequently asked questions
What does A01 mean on a Danfoss controller?
A01 is the high temperature alarm: the air in the cabinet is warmer than the alarm limit. Check the door, the load and the condenser before calling.
How do I reset A80 on a Danfoss ERC 213?
Clean the condenser, then set the r12 main switch OFF and back ON, or power the controller down and up. A80 is the only ERC 21X alarm that needs a manual reset.
What does -d- mean on the display?
A defrost cycle is running. It is normal and the display returns to temperature when defrost ends.
What is E29?
The air temperature sensor is defective or disconnected. The controller cannot read the cabinet temperature, so it needs a technician.
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