Your boiler is struggling to detect the temperature of the water being heated for your taps, which means it has safely shut down to prevent overheating.

DHW sensor out of range. DHW sensor measures a temperature outside normal working range.

What causes this fault?

This fault occurs when the electrical voltage entering the boiler drops below the minimum level required for its electronic components to function correctly. The most common reason is an instability in your home's mains power supply or a loose connection within the boiler's internal wiring that is restricting the flow of electricity. In some cases, the boiler's main control board may be incorrectly detecting a drop in power due to a failing internal sensor.