Boiler starting and stopping

Hi all, we have a biasi riva m96a.28smc combi which has started running odd, it lights for anything up to 30 secs and stops for a similar time continually, when hot water is called for or when the central heating is on.
I have scoured the Internet for answers and have replaced the secondary heat exchanger but this has made no difference.
I would be very grateful if anyone has any other suggestions.

 

It may be a temperature sensor fault but more likely an issue with the air flow and diy advice regarding the combustion chamber is not permitted here.

 

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Please select a service and enter a location to continue...

Plumber / Gas Engineer Electrician Builder Decorator Builders' Merchant Plumbers' Merchant Tile Supplier Flooring Supplier
Start Search

Are you a trade or supplier? You can create your listing free at DIYnot Local