Biasi M96.28 Combi - keeps cutting out

[shenque]

Hi there

Our Biasi boiler keeps cutting out, but on quite an irregular basis. It happens with the central heating on normally, and with no hot water being called for.

The boiler cuts out, the red light in the centre of the 3 LEDs comes on, and the left hand light blinks green. Manual indicates this as being "Faulty primary circuit (no water or absence of flow)."

Strange thing is that the boiler will run happily for several hours before this happens. Turning off the electrical supply to the boiler and then turning it back on again resets this and it will run again for a while before it happens again. There's no pattern to the length of time it will run for before cutting out.

Can anyone help?

Cheers

 

[Ray84]

your boilers got a flow switch so that when the pumps running the flow switch makes a contact proving the pumps running. flow switch is made from thin rubber which can deteriorate causing a small hole which means sometimes it will make the switch sometimes not and youll get these problems

Ray

 

[Ray84]

your boilers got a flow switch so that when the pumps running the flow switch makes a contact proving the pumps running. flow switch is made from thin rubber which can deteriorate causing a small hole which means sometimes it will make the switch sometimes not and youll get these problems

Ray

 

[Agile]

A holed diaphragm is not a likely cause in my experience.

The later microswitch used with a pastel blue cover hardly operate the switch even when everything else is correct.

If the pin is pushing out reasonably hard so it would be difficult for a female to push it back in then its permissible to bend the lever about 1 mm to give it a little assistance!

If its easy to push back then the cause will need investigating and dirt in the pump impeller is one possibility but other flow related causes are also possible. Dirty system water is a useful indicator.

Tony