Danfoss E16

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. As S2 is a regulating sensor, regulation can revert to the S44 safety-delay mode while the fault persists, and the alarm relay activates at high priority.

Symptoms

• Display shows E16 when the alarm is recalled.
• S2 temperature reading is invalid or pinned at an extreme.
• Front-panel LEDs flash to signal the regulation error.
• Controller may show the S44 delay status while the regulating sensor is faulty.

Common causes

• S2 sensor cable insulation has failed, shorting the conductors.
• Moisture or water ingress at the S2 sensor or terminal.
• Internally short-circuited S2 temperature sensor.
• Crushed or pinched sensor cable shorting against a metal surface.

Diagnostic steps

1. 01

   Recall the alarm code

   Press the top button to display E16, then press again to cancel the active alarm before troubleshooting.

2. 02

   Inspect the S2 cable for shorts

   Power down and examine the S2 cable for crushed, pinched, or water-damaged sections, especially where it passes metal edges.

3. 03

   Measure the S2 sensor resistance

   Disconnect S2 and read its resistance; a value near zero confirms a short in the sensor or its cable.

4. 04

   Replace the S2 sensor

   Install a new sensor of the correct type, protect the cable from moisture, and confirm E16 clears once power is restored.

When to call a professional

A short on a regulating sensor disables proper control until it is fixed. If you cannot isolate the short or the sensor sits in a sealed evaporator location, have a refrigeration technician trace and replace the S2 circuit. They will confirm the controller reads a valid S2 temperature again and re-verify regulation. Untrained work inside an energised control panel risks both shock and incorrect re-commissioning.