Main Combi 30 HE

[FlowGas]

Hi Guys,

I do very little breakdown/repair work. I have a Main combi 30 HE, when DHW demand is created I can hear the pump turning but noting else happens. No ignition etc. I'm leaning towards replacing the air pressure switch or fan, just after some advice and guidance from yourselves.

thanks
Jay

 

[dmheat]

Does CH work? If it does forget fan and aps first and foremost.

if CH works but dhw doesn't, check pressure differential valve (dhw), and pump proving switch, both are diaphragm type fitted with micro switches on left hand hydro block

 

[FlowGas]

It doesn't fire up for CH either, the dhw pressure differential value and diverter manifold were replaced just a few weeks ago.

 

[dmheat]

Ok no probs. What fault lights are you getting? APS is pretty common on these, check if fan is getting 240v, if not,check aps,sensing tubes,and fan venturi. If 240v at fan but not running,replace fan