E4
Danfoss Ally Valve Calibration / Stroke Learning Failure

E4 error on display; thermostat cannot complete valve calibration and may show fully open or fully closed symbol continuously.

Advertisements

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Advertisements

Possible Causes

Incorrect valve adapter installed, Thermostat not fully seated on valve body, Valve stroke outside expected range, Worn or incompatible radiator valve (e.g. non‑Danfoss M30x1.5 without proper adapter)

How to Fix / Troubleshooting

Safety first: Remove batteries before adjusting the radiator thermostat. Do not force the valve or thermostat body.

Steps:

  • Confirm valve type: Identify the radiator valve (e.g. Danfoss RA, RAV, RAVL, or M30x1.5). Ensure the correct Danfoss adapter ring is used according to the Ally installation guide.
  • Reinstall adapter: Remove the adapter and reinstall it firmly, making sure it is not cross‑threaded and sits flush on the valve body.
  • Seat the thermostat correctly: Mount the Ally head straight onto the adapter and tighten the clamp or ring nut until snug. The head must not wobble.
  • Restart calibration: Insert fresh batteries, then start the valve calibration procedure (the motor will run the pin in and out). Do not touch the thermostat during this process.
  • Check valve pin travel: If calibration still fails, remove the head and verify that the valve pin moves freely and has sufficient stroke. A seized or very short‑stroke valve may need replacement by a heating technician.
Advertisements

Repair Difficulty

Medium 3/5

Required Part

Danfoss Valve Adapter Set for Ally Radiator Thermostat
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements