Boiler Limit Stat help needed..

[ManxMax]

Hi Chaps,

I finally managed to get my old Trianco Eurostar combi 70 going, but a least once a day the boiler limit stat shuts it down and the button on it has to be pressed. Does the stat need replacing of is something else causing it to trip?

Also, anyone know why the DHW doesn't work with the CH running but does when it's not?

Many Thanks
Max

 

[Burnerman]

Hi Max - more fun?
I think these two symptoms could well be connected...presumably your combi has a diverter valve that switches produced hot water between the DHW and CH side?
I suspect that the water circulating pump is being switched off too soon - so the residual water in the boiler gets very hot, tripping it out.
I've replaced a couple of these phial stats to no avail, much to my embarrasment!
See if there are any other comments first though as I'm not that familiar with diverter valve controls.
John

 

[ManxMax]

Thanks John
sounds like a good theory, I'll check it out.
Max