What does Danfoss E1 mean?

E1 is the Danfoss controller's internal-fault message, shown on EKC and EKE series controls such as the EKC 313 superheat controller. The controller has detected a problem with its own electronics or program rather than with an external sensor or input.

What does Danfoss E15 mean?

E15 indicates a cut-out (open-circuit) on the S2 sensor of a Danfoss EKC controller. The S2 input has lost its signal, so the controller can no longer read that temperature. Because S2 is a regulating sensor, regulation may switch to a safety delay mode (status S44) while the fault is present.

What does Danfoss E16 mean?

E16 indicates the S2 sensor on a Danfoss EKC controller is short-circuited. Unlike a cut-out, the input reads a near-zero resistance, so the controller flags the S2 signal as invalid.

How do I configure defrost on a Danfoss EKC 301 evaporator controller?

Access the defrost settings in menu r-. Set r-01 for defrost type (0=electric, 1=hot gas, 2=off cycle), r-02 for defrost termination temperature (typically +12°C for electric), r-03 for maximum defrost time, and r-04/r-05 for defrost interval hours. Always verify the drip time r-06 is set to allow condensate drainage.

What is the Danfoss AKM system and how does it communicate?

Danfoss AKM (Adap-Kool Manager) is a supervisory control system that communicates with EKC and AK series controllers via LON or RS485 MODBUS. It provides centralised monitoring, alarm management, and data logging for supermarket refrigeration systems. Ensure correct protocol selection in both AKM and controller settings.

How do I manually defrost a Danfoss Optyma refrigeration unit?

On Optyma Plus units, press and hold the DEF button for 5 seconds to initiate a manual defrost. The display will show 'dEF' during the defrost cycle. For Optyma Slim Pack units, access manual defrost via the EKC 102 controller by pressing the up and down arrows simultaneously for 3 seconds.

What does Danfoss fault code 8 mean on AK-CC 210 controllers?

Fault code 8 on the Danfoss AK-CC 210 indicates a sensor fault — typically S3 (air temperature sensor) open or short circuit. Check sensor resistance: at 0°C it should read approximately 10kΩ for NTC10k sensors. Replace the sensor if resistance is out of range or if wiring shows continuity issues.

Refrigeration

Danfoss error codes, decoded.

Look up any Danfoss fault code below. Each one is grounded in Danfoss's own service documentation — the meaning, the symptoms, the causes, and the steps to clear it.

By Octavian Ghindea

Co-founder & CTO · Reviewed August 2026

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Danfoss sits in our Refrigeration coverage. Every page here is transcribed from the manufacturer's manuals, not scraped from forums.

What error codes does Danfoss display?

Tap a code for the full breakdown — meaning, symptoms, causes, and fix steps.

Fault in controller

E15

Cut-out S2 sensor

E16

Short circuited S2 sensor

E17

Cut-out S3 sensor

E18

Short circuited S3 sensor

E20

Fault on signal from Pc (condensing pressure transmitter)

E39

Fault on signal from P0 (evaporating pressure transmitter)

A11

No refrigerant has been selected

A43

Step motor fault (valve output or phase)

A45

Regulation stopped — main switch off (standby mode)

E29

Sair sensor error — air temperature sensor

E27

Def sensor error — S5 evaporator sensor

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