Viessmann boiler error 4FE

Without reading the manual first, it is impossible to know what the error 4FE on your boiler means.

A broken thermocouple may cause the error code 4FE. A thermocouple is an electronic component that measures the difference in temperature between two points. If this component is broken, it will show a fault light, and the system will not work correctly.

With this error, the boiler will not start.

Error code 4FE is an error that appears on the LED display when the boiler will not start. Various reasons, such as a damaged starter relay or wiring, can cause the error code if you encounter this problem and want to learn more about possible solutions.

There is an error code 4EF on my viessmann boiler. What does this mean?

It is possible that there is a problem with the water pump or water tank and that the machine cannot produce enough hot water for the property.

This error will appear on a boiler if the sensor detects the water level is too low.

What causes this error?

The sensor will detect and display this message when it detects that the water level is too low.

What do you need to do when this happens?

If you see a 4FE message, first check that the sensor is working properly, close the doors of your boiler (to avoid air getting in) and refill your boiler with water. If it doesn’t readjust after a few minutes, go get a technician.

Why does this happen?

The sensor’s detection depends on water height, so when it’s too low or too high, it will display an error message.

This is a boiler error code that often appears at times of malfunctioning. It usually indicates a build-up of limescale and sediment on the heat exchanger. You will need to clean the appliance with hot water and vinegar to solve this problem.

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