Biasi riva , Fault

[E4gas]

Looked at a biasi riva combi today , in a restaurant it only dos the hot water , it now plays up on hot water demand , leave tap on boiler cuts in & out , it only had 1 rad on the heating system , now that's been taken off and no link / by pass fitted would this cause the boiler to play up , it was taken off two months ago and been working fine , till last week ..

 

[e/bourneplumber]

it could be that, but i would think that the bypass would be used when the tap is turned off - diverter valve moving the heat away from the boiler. could be something more simple like a thermistor, not sure if it has 2, or the plate heat exchanger scaled.

 

[e/bourneplumber]

or just a thought, could be the diaphragm in the water section of the diverter valve split

 

[E4gas]

or just a thought, could be the diaphragm in the water section of the diverter valve split

Checked that , all ok

I think I descale plate next week, It won't do any harm cleaning it , landlord will pay