Noisy boiler, Is it scale or something more sinister (Link to video)

[MidfieldGeneral]

We moved into our house a year ago. Before that it was more or less unoccupied for 3 years.

The boiler has always been a bit noisy but we are noticing it even more now as the kitchen ceiling is down at the moment exposing all the pipework. I'm wondering if it is scale and a powerflush would help.

Or perhaps its something else. I have uploaded a video of the offending item (a potterton Profile) at the following URL.

YouTube - VID00059.AVI

Any thoughts or suggestions most welcome.

Cheers,

Rob

 

[Blackcatgas]

It does sound like kettleing, a new pump might help (does the heating work ok? rads get hot etc?) a powerflush will help, a localised (to the boiler) power flush with a descaler will be even better, if that doesnt work then there are acids that can be used to clean the heat exchanger, this is really tricky though and you have to know what your doing (I have never done an acid descale btw).

 

[MidfieldGeneral]

Hi There,

The heating seems to work absolutely fine. All 5 rads get warm and it does the job. Just a bit noisy and alarming. There is a pump below the boiler which looks OK and the noise does not emanate from there (it sounds like it is in the pipework just inside or above the top of the boiler curiously. Is kettleing when the boiler itself develops scale (literally like a kettle)?

 

[MidfieldGeneral]

Could it be air in the system? I had a look at the hot water expansion tank in the loft and aside from having a fair amount of red sediment the balcock seemed to be in GWO and the exit out to the system looked clear.

 

[MidfieldGeneral]

There was a bottle of inhibitor and a sticker saying it had been topped up in 1997. Possibly time for a bit of TLC?

 

[Blackcatgas]

Kettleing

Hi There,

The heating seems to work absolutely fine. All 5 rads get warm and it does the job. Just a bit noisy and alarming. There is a pump below the boiler which looks OK and the noise does not emanate from there (it sounds like it is in the pipework just inside or above the top of the boiler curiously. Is kettleing when the boiler itself develops scale (literally like a kettle)?

Kettleing occurs when either the heated water cannot circulate quick enough out of the boiler (poorly pump) or there is patches of scale in the boiler heat exchanger causing un uniform hot spots, when the water hits theses hotter spots it boils instantly causing the noise.

 

[Blackcatgas]

It does also sound a bit rattley like there is some debris in the pipes, bit of solder, grit etc.Ive listen to it again and again and without being there I cant be sure.

 

[MidfieldGeneral]

Thanks, Thats helpful. Think I may go ahead and get the system powerflushed.

Fingers crossed thats all it needs. Will the powerflush do anything for the scale inside the boiler or is the boiler taken our of line when the system is flushed?

 

[Blackcatgas]

all the system is flushed, the boiler is run ocasional during flushing to bring the temp up to make the flushing chemicals work better.

 

[MidfieldGeneral]

Worth a bash then!
Powerflush is booked in for tomorow. Will post back here to let you know how it goes in case its of interest.

All the best,
Rob

 

[hihowudoin]

Could it be fan grumbling, IMHO i would get a GSR engineer in to check out boiler before going to expense of powerflush.

 

[MidfieldGeneral]

Hello Hihowudoin,

I don't think its fan noise but it might make sense to get it checked over. We have a GSR engineer coming tomorrow to do a drop test on the new pipework for the gas fire and I was planning to ask him what he thought anyway.

Cheers,

Rob

 

[Plumbstar Tom]

good idea

Would be appreciate if you post results back hear

you could always try fernox's noise reducer, designed for combating kettling

 

[MidfieldGeneral]

Apologies for not updating this thread at the time of the flushing. After the powerflush the system was initially quite noisy. But then after bleeding the rads of some trapped air it quickly quietened down to a much more acceptable level. Then after about 2 or 3 weeks of good running it began to get noisy again. I'm now beginning to think it IS kettling.

The very interesting thing is that you only get the noise when the CH is on as well as the HW. IF you run the boiler with just the HW there is no noise. So it leads me back to the idea of something in the pipes, maybe steam from the water boiling due to kettling.

Perhaps the pump is not working well enough to shunt the water around.

I am going to experiment with turning the heat down to minimum (so in theory the water might not boil on contact with the hot spots if it is kettling). That said if it WAS kettling I would expect the noise when just the HW is on...

The temperature knob on the boiler is et to 3 and the water is scalding when it comes out of the taps after a few moments so will try turning it right down to 1 and see what happens.

 

[WaterTight]

The very interesting thing is that you only get the noise when the CH is on as well as the HW. IF you run the boiler with just the HW there is no noise.

And how about CH on it's own? Your HW mode pumps water round the coil in the cylinder. CH pumps it round the CH circuit which sounds like the cause of the struggle.

 

[MidfieldGeneral]

I Don't think you can turn the CH on, on its own from the timer clock (HW automatically comes on with it). I could turn the boiler temp right down and put the CH on.
Will try that now.

 

[MidfieldGeneral]

Yes, The really annoying noise is dependent on the CH. In fact the noise is worse in the room just above the boiler. When we had the ceiling down in the kichen before the powerflush you could almost follow the noise as it moved up out of the boiler and into the pipes which run through the joists. That was what made me think it was scale that floated up out of the boiler and sank back down when everything cooled off.

 

[MidfieldGeneral]

The pump below the boiler only seems to be activated when the CH is on. If the HW is on, on its own there is no noise and the pump doesn't appear to be running (when you touch it you can't feel any vibration). Makes me wonder what is pumping the water round the coil in the cylinder. The cylinder is in a cupboard in the room directly above the boiler. Is it possible it could be heated by convection without being pumped, or maybe there is another (quieter) pump somewhere for the HW. Seems pretty odd to be honest...

 

[aceservicing]

You have old style trv above boiler and flow is wrong way,,,,,,,,,,,,,,

 

[aceservicing]

Nice installation

 

[MidfieldGeneral]

You have old style trv above boiler and flow is wrong way,,,,,,,,,,,,,,

Hi there,

Could this be the cause of the noise?

We have been soldiering on with the boiler despite the noise hoping to get through to next summer when it we may get a loft conversion done (and hence probably anew boiler and pressurized tank in the loft room).

Many thanks for any advice!

 

[MidfieldGeneral]

Hi WaterTight,

sorry for not getting back to you and others on this thread sooner. We are some months down the line and the noise is annoying but tolerable. It would be nice to find a resolution though. Most of the GSRs I have spoken to have immediately said that given the age of the boiler (its a Potterton Profile) there is little point throwing good money after bad trying to repair it (particularly if it is the heat exchanger/kettling) and that a new boiler would be more efficient and cost effective in the long run. I take their point and given the higher cost of callout fees in London they are probably right.

However because there is no noise when the boiler is on without water pumping round I DON'T think it could be kettling (as in theory when the HW only is on, water is rising to the tank by convection and is going over the exchanger more slowly than when it is being pumped by the CH pump. So kettling should be WORSE.

In fact there is no noise when only the HW is on which points to either air or scale in the pipework (I'm guessing).

Since the last posting the fitter who did the power flush has replaced the pump as he thought that because the noise did not occur when the pump wasn't running it had to be the pump.

This did not fix the fault and so I'm not keen to use him any more (as you can imagine).

We have had a powerflush so if that was done correctly it can't be scale.
We have bled the radiators and there is no air trapped.

So can anyone make any further suggestions?

Should I get press ahead and get a new boiler (given that this on its own may not fix the problem).

Should I get a new GSR engineer in to take a look at the system and if so can anyone give an idea of what this should cost?

All help gratefully received.

Rob

 

[SafeGasInstall]

hi Rob ,

Some times I do work for the housing associations , and this is the boiler that we replace the most ! Must have removed hundreds of those boilers and never seen any scale in the pipe work .
Many of the tenants have been so please of boiler been taking away and new one installed as they were complaining of the same noisy system
and when they had the new boiler fitted they could not believe how quiet they are .
99.9 % of all them central heating systems were full of sludge and the actual pipe work had like 2-4 mm sludge internally on the pipe !
Replacing Profile to a modern boiler will be your best call imho , but do not forget all rads manually flushed and system must be flushed out again and must get a Central heating cleaner installed ! This is how we deal with aged system and never had a call back .
Most of the customers do listen to all steps needed to clean the system correctly when new boiler is installed and we never hear from them until first service on the boiler !
Should you need any help I can assure ,you will not look back after using Safe Gas Install Ltd.
I am in London too

 

[Sullivan]

I had a similar problem with an old boiler some time ago and got a plumber to have a look and he flushed the system which resulted in a little improvement only. Being handy, I had a go myself and stripped the boiler sufficiently to get access to the heat exchanger. Visually it looked fine on first inspection but when I examined it closer I discovered the area between the fins was approximately 60% blocked with corrosion and dirt. Carefully working from the bottom I removed the material with a long reach thin screwdriver. The dirt was obviously causing hot and cold spots in the heat exchanger causing the water to move eratically. Following the cleaned exchanger the boiler worked perfect and was totally silent. As your boiler was idle for a long period, it may be worth having a look to see if the exchanger needs to be cleaned.