My Glow Worm 24cxi keep coming up with f5 error

[rpstorm]

My Glow Worm 24cxi keep coming up with f5 error when i use the shower or running a bath.

every time the f5 error comes up i have to

Take off outer cover.

Take off inner cover.

Over heat thermostat is top left. (little red button on it)

Press little red button.

Refit all covers.

Turn on.

can anyone please help I'm at my whits-end

many thanks

 

[lightning]

Is the pump running does it overheat in secs ,mins or hours

 

[Agile]

You should not be opening the inner combustion chamber cover as you are not gas registered.

The plate heat exchanger is probably blocked.

Tony