It works fine on dhw but from cold on heating it usually does flame failure , from cold dhw works fine , I know it will be suggested low gas rate but surely that would affect the dhw as well , any pointers great full received .
I see that you are posting a lot of questions about different boilers.
But you are not registered for the CC part of the site reserved for Gas Safe engineers.
The obvious advice is to register for the CC if you are Gas Safe.
If you are not Gas Safe then obviously you should not be working on gas appliances and you should stop putting people lives at risk and risking prosecution.
I haven't asked a question for a long time , now I know why I gave up on this site . what is the point of a d I y forum if all you get is abuse and unhelpful answers .
But looking at your posts shows that your not doing DIY, you're trying to fix other peoples boilers as tony said.
So either register for the CC where there's all the help and experience you could wish for, or eff off if you're an illegal.
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...
Are you a trade or supplier? You can create your listing free at DIYnot Local