Nefit TopLine 4A 218

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Error code: 4A 218

CauseThe supply part of the bi-sensor or supply sensor has measured a central heating water temperature that is higher than 105 °C.

Depending on the type of boiler, it is equipped with a flow sensor or a bi-sensor.

Other symptoms:

No central heating operation. No hot tap water.

Step 1

Are the service valves open?
Step 2

Is the central heating water pressure at least 1 bar?
Step 3

Has the boiler been properly vented?
Step 4

Are enough radiators, convectors, etc. open?
Step 5

Are the supply, safety and return sensors in order?
Step 6

Check the pump
Step 7

Check the pump control.
Step 8

Is there a central heating system that can completely shut down?
Step 9

Is there a bypass or open distributor in the central heating system?
Step 10

Is the bypass or open distributor OK?

This malfunction requires the help of a professional