baxi 105e thumping noise

[seanmfc]

hi

over the last 18 months this boiler has had every major new part the last being a external expansion vessel about 6 months ago i noticed the other day thumping noises when reaching 2 bar pressure when ch is on looking outside at the overflow water was comming out (trickle and hot) when the hw is turned on is does the same only quicker when left eventually it cuts out and the fault code says a pump problem im mystified because everything works

i have a video of what happens if someone knows how to put it up

thanks if anyone can help

 

[5544]

not really much to go on but,
1. when you had the expansion vessel changed, did they change the pressure relief valve,- asking this as the PRV is set to lift at 3bar and yours is dribbling at 2bar. i would suspect they did not.

2. the banging noise does sound like the water in the heat exchanger getting too hot. (since it is affecting both HW and CH)
on central heating mode the burner will modulate to whatever the system is set at, and also its size, but with hot water it will give you full gas, hence the reason why it happens quicker and locks out on the over temp cut out.

initally i would agree with the fault code that is coming up, and it does sound like a flow problem. this could either be due to a pump that is not working propely and not circulating the the water round quickly enough to disipate the heat, or there is a partial blockage in your heat exchanger which is restricting the flow.

Q. what is the pressure set at on your boiler when cold. should be 1bar?

either way it would be best to get a registered guy in to hear the noise. it might be that they can identify the problem quicker and in the long term save you money. Might be that they could flush out the heat exchanger properly. They can then also change that pressure relief valve.

kindest regards

 

[seanmfc]

hi

everything was done and correct i have justed flushed the system out and repressurised and have now noticed a leak upon investigation i have found the pipe from the diverter valve has been kinked therefore its now leaking i now think this is the problem hopefully

 

[seanmfc]

5544 you got it right it was the heat exchanger which had a blockage in it

thanks for your help