Boiler keeps stopping & starting every 30 seconds or so

[glens73]

I have a Potterton Siuprima 30 boiler, it keeps stopping and starting every 30 seconds or so, radiators not heating properly and very little hot water. The boiler has had a new fan fitted 3 weeks ago and a new control panel about 3 months ago.

Would anybody have any idea what may be causing this?

The same guy, fitted the control panel and fan, but won't now return my calls

 

[tininho]

Hi,

Depends really... Is the red lock-out indicator illuminating during the process???

Sounds like either your mid-position actuator is jamming and not motoring fully over...... or an air lock, possibly a choked cold feed if it is on an open vented system (though this is unlikely....)

Martin

 

[Agile]

Its not an immediately obvious cause but is quite likely to be gas/combustion related and we cannot advise DIY repairs on gas.

The obvious advice would be to get whoever replaced the fan to come and see it as the immediate thought would be that he did not diagnose or fix the problem properly. But it could also be an unconnected different fault.

Tony

 

[Red_Man]

Thermistors?

 

[sambotc]

I'd be checking the pump before anything else.

 

[tininho]

it would run for longer than 30 secs if the pump was at fault..... would be pretty noisy too..... suppose the venturi could be partially blocked, but still reckon the mid-pos valve (or zone valve) is most likely....

Martin

 

[Gasman77]

could be a hole in the inner flue causing vitiation within the combustion chamber - id get someone out pronto and leave it off

 

[seco services]

Sounds like either your mid-position actuator is jamming and not motoring fully over

if it wasn't motoring over then it won't be calling for heat.

 

[tininho]

Indeed... However, I have in the past come across faulty motorised valves, where the syncron is beginning to sieze up to the extent that the end-switch makes and then drops out repeatedly.....

Just a thought