Baxi bermuda 552 back boiler banging noise

Not open for further replies.
Sponsored Links
Smally (and all)

Good news my problem is solved. I went ahead and did power flush, air removal from the system and (this is important) installed small pressure tank in the loft on feeder tank with pressure gauge. I know this is not necessary for convensional gravity system but believe me this stoppedbanging noise. After doing all this in week's time banging started again and i went up in the loft and noticed that the pressure has dropped to 0 so did radiator air bleeding and increased pressure in th tank by letting water go in )usually there is a valve on the pressure tank that doesw it..i was told..) so then next day its silent. THE BANGING WAS ALL TO DO WITH AIR GETTING INTO THE SYSTEM. The only way to track this was to install pressure tank and gauge on the feeder tank. By doing this its like close system. So if there is pressure drop, we know the air is into the sytem and bleed radiators and tight all valves on the raditors etc...then increase the pressure to 1.5 (bar??) and it damn silent. i spent nearly £600 on full power flush, radiator bleeds, tank installation etc. but i am happy now.


i definitely recommend fitting pressure tank like this. If you need more info on this then email me on [email protected] and i will be happy to discuss further. By the way i am not plumber or engineer so i am not selling my services here. And if this works for you then do send me homemade cookies!!!!
Baxi 552 should not be fitted on a pressurised system it does not have the proper safety devices.
Sponsored Links
Baxi 552 should not be fitted on a pressurised system it does not have the proper safety devices.
rshah said:
installed small pressure tank in the loft on feeder tank with pressure gauge
But from reading what the OP writes, he has not turned it into a sealed system, just put a closed vessel with a pressure gauge into the feed from the F/E tank. The F/E tank is still open to the air, so it can't be a sealed system.

The pressure gauge seems to be measuring the static head, which will drop if air gets into the system.
I read it as still having two but how can he raise the pressure to 1.5 bar the water would just go up the open vent or cold feed into the header tank as opposed to down into system
I know this thread is very old, but these boilers are still out there, this might help someone who finds themselves here.

I had a 552 heat exchanger develop a leak. My engineer removed the HE, split it and fitted new gasket and then re-installed it...job done sorted.
I do not live in this property.
Some time later I was there and found that the boiler was banging very loudly when at its maximum temperature just as the boiler stat woud click off.
Even though no longer lit, it would continue to bang for 5 to 10 seconds.

I had the boiler stat replaced, no effect.
I flushed and re-filled, no effect.
Probably tried some other things, no effect.

In desperation I concluded that the HE was scaled up and had hot spots causing the water to boil.
I got hold of a good quality second hand heat exchanger and called my engineer to come and fit it.

When the old HE was removed I noticed that the plastic insert 'water spreader' was smashed.
It had been smashed when the HE was removed for the original leak.
New spreader purchased and fitted, no banging, quiet as ever.

The heat exchanger has 4 water channels and without the spreader the pumped water will pass down 2 channels allowing the other 2 channels to boil as they have no flow.

Spreader ,Not necessarily damaged during heat ex repair these do fall apart over the years so may have been ok at the time

DIYnot Local

Staff member

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.

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

Not open for further replies.
Sponsored Links