Alpha Ocean 280e Overheat Thermostat light on

[deejay88]

I recently replaced the DHW Flow Diaphragm to cure a leak and now the 'Overheat Thermostat Has Operated' red light is on and the boiler won't operate. The white reset button had no effect.

The fault finding chart suggests a problem either with the overheat thermostat itself or the neon PCB. Just seems strange that it has failed at the same time I replaced the diaphragm? Any thoughts on what could have happened and what the most likely cure?

Thanks.

 

[Rampage77]

press the red reset button

 

[deejay88]

I did try pressing the red one but that had no effect either...

 

[deejay88]

Any more thoughts please?