Buzzing Boiler

[Ben565]

Hi,

I have a Potterton Promax HE boiler, from what I've read they are crap! fortunately it is covered by homecare. Unfortunately thus far they have been unable to get to the bottom of the problem.

Initial problem was a water leak, but upon investigation various other faults were discovered which resulted in the whole boiler being totally stripped down and rebuilt with a load of new parts (Heat exchanger, ignition probes, door seals, and also the pump) Some pipework was also replaced due to limescale blockage. The boiler was all set up, tested and bang on spec (better in some case for CO2 etc)

Ever since then however it has been really noisy, whenever the boiler fires up it resonates throughout the house, at first I was watching the TV and thought it was a plane droning overhead. On one occasion I could feel the boiler casing vibrate, it seems as though the vibration was transmitting through into the wall.

I have also heard various other noises:
Water trickling sound from boiler
Water gurgling/trickling sound from magna tec device
A strange noise from around the pump/header tank feed pipe area, almost like there is something metallic stuck in the pipe and rattling around inside.

I should also add that the pump is nowhere near the boiler, system has been bled.

I'm not looking for any detailed DIY open-up-your-boiler-and-gas-yourself advice, just wondering what the problem may be, it would really help to be able to highlight the problem to the engineer. He did put a lot of hard work (several hours) into sorting the initial problem, I'm sure he thinks I'm pulling his leg about it being noisy now as he can't hear it. of course it behaves when he comes to look at it.

 

[Agile]

I am pleased that your "homecare" were prepared to put the effort into fixing it.

You will read a thread here today about someone who has not been so lucky.

Unfortunately a "noisy" but working boiler does not get much priority at busy times when others have no heating at all.

I cannot tell you what it is as the only way to diagnose a boiler fault is in front of the boiler!

Tony

 

[Ben565]

Yes I've read some bad stories about Homecare, only fair that when one of their engineers goes the extra mile I should say so.

They are still investigating the problem, as you say it's obviously not a priority over someone with no heating at all. Having been without any heating, hot water, or electric for the last month (during renovation admittedly) I have an idea what that's like.

I read that thread about that other guy with no heating, not a great situation to be in I hope it gets sorted for him.


As an electronics engineer I can appreciate it isn't really possible to diagnose faults without having it in front of you, worse when it's intermittant. Not knowing how a gas boiler works I just wondered if there was any common culprits or anything within the boiler that could cause a vibration, like a fan or motor or something, it appears to be burning well enough. I suppose if it was that obvious though the engineer would have already looked at it.

 

[Boilerman2]

It is screaming at you in Boiler language to arrange to have it put down!!

 

[Ben565]

Haha yes it may well be, hopefully it can hang on a bit longer, to be fair it's done good service for 10 years. My dad's got a Worcester boiler which is great so gonna have to start saving I think.

 

[john320d]

Try different pump speeds.

 

[DP]

Some of the noises you mention may well be due to incorrect gas valve settings (CO2 readings- how can it be spot on and better than what it should be).

During combustion your boiler produces gases, the mix of which is critical and is ascertained by use of flue gas analyser. You should have been given a printout of the test and will be able to compare the figures shown in boiler manual.

 

[Ben565]

Tried different pump speeds, didn't make a massive difference, if anything worse when slower and better when higher, but really just changed the pitch of the noise (and made a lot of extra noise from the pump when on max)

There were 3 readings the engineer showed me, some were spot on and some were apparently better than spec, I can't recall which were which.

I've also heard a trickling sound from the boiler when it is switched on and operating. Which is odd, I would expect any water in the boiler to be under pressure not trickling.

It has a fabric burner which the engineer is going to upgrade to the new ceramic type. Can't see that this is the problem as it was ok before, but Potterton obviously changed the design for a reason.

I've no intention of taking it apart, but I did have a read of the service manual, it seems the only moving part is a fan. A duff fan could make the kind of droning noise I'm hearing. Presumably that would mess up a lot of other things too though.

 

[Ben565]

Sounds a lot like this

https://www.youtube.com/watch?v=O-bPMWyFNoI

 

[underwurlde]

I'm probably posting for the sake of posting, but if the noise is attuned to the speed of the pump then surely it must be pump related or moving water related (e.g. cavitation). Resulting noise being transmitted through water pipes, amplified by radiators etc.

Guessing amature of course whom is now awaiting the flaming of one's ar$e

Andy

 

[petit_pablo]

2 different noises there, the trickling noise is air in the system.
The droning will be the gas valve or something along those lines. Depends exactly what he's replaced.

 

[Ben565]

Just an update to this.

You could be right about air in the system, I felt one of the upstairs radiators last night and was stone cold. I opened the bleed valve and no kidding it was a good 20sec or so before all the air had come out. I was up and down several times after that bleeding a little more air out each time. It did seem quieter after that.

The homecare engineer visited today (pre arranged) and replaced the old fabric burner for a ceramic one. He also fine tuned some settings ( I don't know which) he also reduced the power slightly so it isn't working as hard. turned the wick down by about 4kW I think.

There was still some noise from the pipework around the pump. I traced this to the pipework directly after the pump, there was a valve which I turned slightly counter clockwise (quarter turn at most) and this immidiatly stopped the noise.


So looks like problem solved.

 

[Ben565]

Spoke too soon I think, still making the same noise, albeit at a reduced level. Why on earth is it buzzing and humming through the walls of the house!