Heatrae sadia boiler cutting out after 20 mins

[m4tty]

Hi,

I've got to go look at a heatrae sadia electric boiler which is cutting out after 20 mins. It's for a friend but I've never had anything to do with these before so am asking for any pointers.

Any help/info at all would be greatfully appreciated .

Thanks

 

[ProDave]

Is the flow okay? boiler overheating because not enough flow in the water circuit?

 

[davetheglitz]

20 mins seems a long time before it overheats. I presume this is an electric boiler for instant heat only.

If supplying radiators or a tank could there be a pressure build up? if so suspect an expansion vessel.