Which Danfoss controller is on your walk-in — and what do its codes mean?

Danfoss electronic controllers run an enormous share of commercial refrigeration, and several of its families end up on walk-in coolers and their condensing units: the ERC 211/213/214 controllers found on cabinets and walk-in control panels, the EKC 202 and AK-CC 210 case and room controllers, and the Optyma Plus controller mounted on Danfoss condensing units that serve walk-ins. The code language is consistent across them: E-codes are sensor and electronics errors (E29 is the air sensor, E27 the defrost sensor), A-codes are alarms — temperature (A01/A02 or A1/A2), door (A04/A4), voltage protection (A99/AA1), and the condenser pair worth memorizing: A61 warns the condenser is running hot, A80 is the blocked-condenser lockout that requires a manual reset after you clean the coil.

Some AK-CC models add HACCP logging (A60) that timestamps food-safety excursions. Find your controller family and exact code below for the documented meaning, the safe checks, and when it's a service call.

Which Danfoss controller do you have?

Controller	Alarm codes covered	Page
Danfoss ERC 211 / 213 / 214 Danfoss ERC 21X display; E27/E29/E30 sensor errors and A01–A99 alarms.	12 alarm codes: E29, E27, E30, A01, A02, A99, AA1, A61, A80, A04 and 2 more	Full list →
Danfoss EKC 202 / AK-CC 210 Danfoss case and cold-room controller; E, A and S (status) codes.	16 alarm codes: A1, A2, A4, A5, A15, A45, A59, E1, E6, E27 and 6 more	Full list →
Danfoss Optyma Plus Controller built into a Danfoss condensing unit; A2, A17, A80, A96.	16 alarm codes: A2, A11, A16, A17, A45, A80, A96, A97, A98, E1 and 6 more	Full list →

Danfoss ERC 211 / 213 / 214

The Danfoss ERC 211, 213, and 214 are compact electronic refrigeration controllers fitted by many commercial cabinet and refrigeration equipment makers, and they turn up on walk-in panels as well as reach-ins and display cases. The display normally shows temperature; faults appear as E-codes for failed sensors (E27 defrost, E29 air, E30 condenser) and A-codes for alarm conditions — temperature, voltage, condenser, and door alarms. One code worth knowing before you panic: A45 means the unit was switched to standby on purpose via its main-switch parameter, not that anything broke. Practical tip: A80 (condenser blocked) is manual-reset — clean the coil first, then power-cycle, or it just comes straight back.

All 12 Danfoss ERC 211 / 213 / 214 codes — meanings, checks, diagnosis and parts →

Danfoss EKC 202 / AK-CC 210

The Danfoss EKC 202 and its successor the AK-CC 210 are panel-mount case controllers used across commercial refrigeration — display cases, cold rooms, and walk-in evaporator control, often tied into a store's front-end monitoring network. Faults show as short codes plus a plain-text line on the display: E-codes are defects (E1 controller fault, E27 and E29 sensor errors) and A-codes are alarms (A1 high temperature, A2 low, A4 door, A45 standby). Practical tip: A45 standby doesn't trip the alarm relay on the AK-CC 210 — a box someone left in standby can sit warming quietly, so treat an unexplained 'Standby mode' display as urgent, not informational.

The Danfoss AK-CC 210 is a case controller for commercial refrigeration — cold rooms, display cases, and walk-in evaporator sections, frequently networked into a central monitoring system that logs its alarms. It reports with the same short-code convention as the rest of Danfoss's EKC/AK line: E-codes for sensor and hardware defects (E25 and E26 are the S3 and S4 air sensors) and A-codes for alarm conditions, including A60, a dedicated HACCP high-temperature alarm for food-safety monitoring. Practical tip: when A60 shows, log the actual product temperature immediately — that alarm is a compliance record as much as an equipment warning, and your notes matter at inspection time.

All 30 Danfoss EKC 202 / AK-CC 210 codes — meanings, checks, diagnosis and parts →

Danfoss Optyma Plus

Danfoss Optyma Plus condensing units — the outdoor or machine-room half of many walk-in cooler and freezer installations — carry their own built-in electronic controller with a small display on the unit. It reports faults as short codes: A-codes for alarms (A2 low suction pressure, A17 pressure safety trip, A80 condenser airflow, A96 discharge temperature) and E-codes for controller defects. Because this controller lives on the condensing unit, its alarms lean toward compressor protection — pressure trips and overheating — rather than box temperature. Practical tip: when one of these codes stops the compressor, resist the urge to keep resetting; the protections exist because forcing restarts is how compressors get destroyed.

All 16 Danfoss Optyma Plus codes — meanings, checks, diagnosis and parts →