HOWLING POTTERTON PROMAX BOILER!

[AndrewD]

We have a boiler that greets the day by howling like a dog! At 4.30 am it starts with a low moan that builds quickly to a reverberating howl that fills the entire house. This goes on for fifteen to twenty minutes with varying levels and pitch with harmonics and groans until it has reached it's running temperature when it slowly dies away to quiet. It started over a year ago with the odd brief sick cow moo which was tolerable but then developed into what we have now.
Our plumber is tearing his hair out. He’s done all the boiler manufacturers have told him to do. All to no avail!
First it was the gas valve…we replaced the gas valve. It’s not the gas valve.
It was the fan…we replaced the fan. It’s not the fan.
It’s the gas and air mixture…he adjusted the gas and air mixture in every which way possible. It’s not the gas and air mixture.
The seals have failed…we replaced the seals. It’s not the seals.
You get the picture!! All this, of course costs money and time!
The manufacturers are now out of ideas. Our plumber is out of ideas. And we are losing sleep!
Someone out there must have come across this problem and have figured out what the hell is going on here. I can’t believe our bloody boiler is unique!
It is a Potterton Promax FSB HE floor standing boiler. We had it installed when our good old faithful Potterton Kingfisher boiler finally gave up the ghost after thirty years good service, only needing the occasional thermocouple replacement to keep it working perfectly.
I'm hoping that someone out there may have an answer before I have to make the decision to rip it all out and bin the lot!

 

[Gasmk1]

get your registered gas fitter to try setting the gas valve properly this needs to be done with a flue gas analyser as per manufacturers instructions if this, also check the burner this burner was known to crack and it’s seals fail.

 

[AndrewD]

get your registered gas fitter to try setting the gas valve properly this needs to be done with a flue gas analyser as per manufacturers instructions if this, also check the burner this burner was known to crack and it’s seals fail.

He has done all of that quite a few times already. He's also had the burner out and checked it thoroughly. Everything in the boiler checks out correctly so far. He has done that whilst talking with the manufacturers on the phone as he did it, reporting back to them as he did so.

 

[Basher]

Seems you are not alone with a noisy Potterton!

GasBoilerForums.com - Information

 

[AndrewD]

Indeed but looking at these video clips ours is not quite the same. Our gas/air mixture is good and correct and our noise is at a higher frequency like a howl rather than a buzzing vibration. Clearly both are to do with combustion or related but, I suspect, different causes somehow. Thank you anyway. Still needing a solution to this.

 

[snowhead]

Has Potterton suggested checking / cleaning the airways through the heat exchanger.

 

[AndrewD]

I don't think so. Our plumber is coming later today to fit a new flue elbow on the top of the boiler as the seal did not look in good condition. Potterton for some reason do not sell the seals seperately so, very annoyingly, you have to have the whole kit. A very strange and expensive way of doing it. I will ask him your question as it was something that I was wondering about. I don't know what the heat exchanger is like not having seen one to examine. Are there many airways throughit and do they get glogged up very much? The fact that the noise dies away once it has got up to running temperature implies expansion plays a part in this unless I'm misunderstanding it all. If it was down to clogged airways wouldn't the noise continue all the time rather than die away?

 

[Chuck]

If someone competent has gone to town on the likely causes of a problem I usually look at less likely possiblities that they may have dismissed prematurely.

E.g. you didn't mention the circulating pump or water pressure in the system. Is the pipework properly secured? Noise travels, particularly at 4am. Are you sure the boiler is responsible and not a dodgy TRV somewhere? Hot water cylinder coils can also make a number of strange singing / humming noises.

Do you have a recording of the noise?

 

[Al Smailes]

We had the same problem (hence me finding this post)… in fact we’ve had it twice and both times the problem seems to have been lack of gas pressure. The first time the meter was largely at fault (not helped by street pipes being replaced by shoving new plastic ones up the old ones) and as soon as the meter was replaced by Cadent (National Grid’s proxy where we live) the howl went away. A year later it came back and we discovered that at certain times of day the pressure at the meter was on the legal minimum (or possibly less at times, we don’t know) and the pipes to the boiler were losing a chunk of it, so we only had 15.5mb at the boiler itself. Apparently some boilers are more tolerant of low pressure than others, but the FSB30HE is in the latter group. Long story short, our long suffering engineer Vince replaced the run with 28mm pipes (with much muttering about how bloody stupid the whole thing was) and, with the boiler getting 18mb+, the howl has gone away. Worth looking at if you have the same problem.

 

[ExPunkLondon]

We had the same problem (hence me finding this post)… in fact we’ve had it twice and both times the problem seems to have been lack of gas pressure. The first time the meter was largely at fault (not helped by street pipes being replaced by shoving new plastic ones up the old ones) and as soon as the meter was replaced by Cadent (National Grid’s proxy where we live) the howl went away. A year later it came back and we discovered that at certain times of day the pressure at the meter was on the legal minimum (or possibly less at times, we don’t know) and the pipes to the boiler were losing a chunk of it, so we only had 15.5mb at the boiler itself. Apparently some boilers are more tolerant of low pressure than others, but the FSB30HE is in the latter group. Long story short, our long suffering engineer Vince replaced the run with 28mm pipes (with much muttering about how bloody stupid the whole thing was) and, with 18+mb at the boiler, the howl has gone away. Worth looking at if you have the same problem.

 

[AndrewD]

The noise is definitely coming from the boiler itself. I have spent ages tracking down the precise location of the noise. The main pump was one early suspect but there is no noise coming from it at all. The noise can be stopped briefly by restricting the air inflow through the balanced flue but as soon as you take your hand away it starts up again. That indicates it's connected to the combustion/flue in some way. The problem is we cannot identify why it's doing it. There is nothing that appears to be wrong. I have recorded the noise on my phone a little while ago but I need to do another one to get the full effect.
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Well here's the thing. We are sort of hoping and suspecting the problem may possibly lie with the seal ring on the top of the boiler where the inner flue fits onto it. That has broken down and needs replacing. It's why my plumber has ordered the new elbow having been told the seals are not sold seperately. He has now been told, when the elbow arrived, that that particular seal only comes with the boiler, not the elbow. It's not listed seperately so you can only buy it if you buy a new boiler!. That's like saying when you wear out a tyre on your car you can only get a new one if you buy a new car. How bloody daft is that!! Nice one Potterton!!! Unbeliveable!

 

[Lou]

(Just bumping a few older threads, they will drop off what is new soon)

Check Out Plumbing News!

 

[Jezclayton]

Late in the day, but I normally associate howling with a leak in the seals on the concentric flue allowing products of combustion to be sucked back into the boiler. The Ideal Icos/Isars were another boiler notorious for this. The OP has not come back since the flue elbow was changed, so I expect that was the issue.

 

[AndrewDan]

Late in the day, but I normally associate howling with a leak in the seals on the concentric flue allowing products of combustion to be sucked back into the boiler. The Ideal Icos/Isars were another boiler notorious for this. The OP has not come back since the flue elbow was changed, so I expect that was the issue.

Yes, that turned out to be the problem. Once changed the noise subsided though it tokk a couple of weeks to happen. The sound got progressivley lower in pitch and duration until it died away altogether. All silent now.