Noise in Central Heating Pipework

[DenG1]

Last night a noise suddenly started up whilst our heating was running. It sounds like rain falling onto a tin roof and is more or less constant. The heating had been on for over 5 hours and the noise started suddenly. The only thing we have done differently is to turn our room stat up from 20 to 22. In January we had a new boiler (Vaillant ecotec plus 428) fitted in our loft which replaced a baxi bermuda back boiler. We had a slight problem with "expansion" from where the new pipework in the loft went through the new holes to the airing cupboard which our heating engineer sorted out, but this is a different noise and seems to emanate from the airing cupboard where all the controls are.

I am fairly confident it is not the 3 port valve, but it is hard to isolate the noise. It can be heard in our lounge in what I believe is the old capped off pipework to the old boiler. And in the 2 bedrooms between the airing cupboard. I called our heating engineer this morning but he cannot get to me until possibly tonight or even tomorrow,(fortunately the heating is working albeit noisily). He suggested it may be air in the pump (it has to run at setting 3 to avoid the dreaded S53 code on the boiler) so my husband has bled all the radiators (no air) and vented the pump, (he says a little air and water came out) but when he switched the heating back on again he says the noise is the same.

Any ideas in case its something simple. My husbands a carpenter but unfortunately heating, plumbing and electrics are beyond him!

We havent been up in the loft as the boiler seems to be working ok as in providing heat and hot water and was pluming nicely when I left for work.

We have an open vent system with boiler, cold water storage and F & E tank in loft, "normal" hot water cylinder in airing cupboard, room stat in lounge, pump, 3 port valve, bypass thingy (thats a technical term) and programmer in airing cupboard.

The system was flushed and inhibitor added when the new boiler was installed and the water that came out the rads and pump was clean.
Finally (sorry to have gone on a bit) when the system fires up from cold, the noise doesnt kick in until its up to temperature so this morning I thought it was just a blip last night as the noise didnt start for about 30 mins, but then once we're up to temperature and it goes off via the room stat and then starts up again its instant noise as the system's still warm.

Many thanks for reading, Denise

 

[su966]

I had the similar problem with my system. I put the actuator valve in manual position to refill. The noise went away. The water in the system is not enough. There is air trapped. Bleed the radiators. And refill the system properly.
Your problem may be diffrrent but it worked for me.

 

[DenG1]

There was no air in radiators and only a little came from pump. How would I "refill properly" ? This is an open vented system and wouldnt have a clue how to refill!!!

 

[su966]

My one is open vented system. There is a valve near the motor. It is normally set to automatic. To refill you will have to pull the lever to the right to manual. This is normally called mid position actuator. I can only explain what is mine. There are three small switches on the actuator. On the left it reads three position. W, M, H. Do not touch this. It is controlled by the switch. For example if you put the system to hot water this switch will automatically move to W, if you turn on central heating this switch will move to H. If you turn on both then this switch will move to M. This actuator opens a valve. You don't need to touch this switch at all.

Switch 2: It is the biggest of the three switches on the actuator. It normally stays on the left. You can gently push this switch to the right. It will stay on the right. Read manual of your actuator. As soon as you push the switch to the manual position the system will start to refill. Switch off boiler before you do this. Give some time for the system to refill.

After refill is done you can restart the system. You will not need to pull back the lever to the left. When you chose central heating or hot water the lever will move back to the left automatically. Do not try to pull the lever to the left. It is automatic.

Switch 3:a small one. Don't touch it.

Read manual for actuator. They have model number on it.

Your system may have different problem such as deposit of limescale in the water or something like this.

I am not a gas engineer. So, try at your own risk.

 

[DenG1]

Just an update on this and would welcome any other thoughts. Got home yesterday, heating had been on about an hour, all lovely and warm but still this noise. Then it quietens right down. Heating engineer called round for a "listen". but of course nowhere near as noisey as it had been previously. He Made minor adjustments to the "gate valves", which had no effect and turned the pump right down to 1, no noise at all. He did say it could be a little bit of debris has dislodged and is rattling round and if so he would come back, drain system, add fresh inhibitor and refill. Unfortunately turning the pump down to 1 meant the S53 code, and cooling rads. Put pump back to 3, very noisey again. Put pump down to 2, rads stayed hot but hot water tank needed boost from immersion after 1 bath as slow to reheat (it isnt when pump at speed 3). So I wondered could it be connected to the pump? I need this to run at speed 3. This morning heating came on as normal at 6, (pump still on 2) no noise, until after 30 mins then noisy again, but after a further 30 mins it quietened right down again. The pump is about 14 months old, not a brand recognised by me from reading this forum, just says on box Compact Circulating Domestic pumps. Many thanks Denise

 

[RigidRaider]

We recently had a similar noise, which I thought was kettling in the new boiler as it would start about half an hour after the CH came on then gradually die away. Then I realised that I could only hear it in the bedroom rad so I had a good listen and realised it seemed to be coming from the vertical leg of the flow pipe into the rad. I turned the valve down slightly and the noise stopped immediately. It seems to me that a small drop of solder from recent boiler replacement work had found its way into the pipe and was jumping around in the flow, not quite able to get into the rad and lose itself. Your symptoms sound very similar.

 

[DenG1]

I'm pretty sure its not coming from a rad. It can be heard in the airing cupboard, the 2 bedrooms either side of the airing cupboard and the lounge chimney breast on what I assume is the pipework to the old back boiler. Our new boilers been in nearly a year tho!!!

 

[DenG1]

Sorry to keep on about this!! Last night on pump setting 3 - lots of noise, turn pump down to 2 much quieter with just occasional noise. So when the heating and water went off last night I put the pump back to 3 to enable me to turn it down to 2 and quieten it this morning (hope this makes sense) When heating & water came on at 6.30 this morning it was noisy straight away but when I turned it down to 2 we had no noise at all. I still would prefer to run on 3 because of the S53 on the boiler meaning everything takes longer to get to temp. 2 more questions, if it is debris in the pipes, if I run just the hot water and not the central heating would I still hear it? Also last night when I adjusted the pump speed everything had been off for over an hour but when I felt the 3 port valve this was still quite hot and felt as if it was vibrating - is this normal or could this be part of the problem. When holding a screwdriver to both the pump and the 3 way valve and my ear it does not seem as if the noise comes from either of these, but could be from any of the airing cupboard pipes. Thanks again, Denise

 

[Burnerman]

Just a thought Denise and it may be quite wide of the mark - but you said your heating man made gate valve adjustments? I presume this was to the boiler bypass. I'm just wondering if the pump is struggling on position 3 and the bypass needs to be opened a little. If you can find the bypass gate valve, try opening it when the noise is there and see if it quietens.....but do mark its original position!
John

 

[DenG1]

Im not at home at the moment so cant upload picture. The pump sits between 2 valves (I think) and it was these that he tweaked. There are 2 other "things" that can be adjusted but am reluctant to touch anything. Just mystified that it happened so suddenly, no gradual build up of noise or anything! If things do not improve I will take a pic and perhaps you could tell me what bits can be adjusted and whats what. Thank You.

 

[Burnerman]

There will be a valve on either side of the pump - these are the ones that are turned off for the pump replacement. So far as I know, they must always be turned fully on.
A bypass is a pipe link between the flow and return pipes to the boiler, effectively connecting them up before the radiators. Sometimes the bypass is automatic, sometimes another gate valve is used to balance the flow through the bypass. This is the gate valve I'm referring to, should it exist.
John

 

[DenG1]

I think I have one of these, but it has a soft grey covering over the end, so I do not know if there are any numbers on it. My heating man definitely did not adjust this. Is it easy to adjust and how do I do it?

Untitled

• DenG1
• 18 Dec 2009
• 1

But as I said I am at work so will have a good look tonight and if necessary get the digi camera out!! Would this cause said noises which appear to be in the pipework if it needs adjusting. Thanks again

 

[Burnerman]

Indeed, this is an automatic bypass valve, which should have been set by the commissioning heating engineer. They are adjustable up to pre set parameters, whereby they take over the bypassing up to that level. There should be numbers on it I think so make a note of it should you attempt adjustment. Do note though, its only a thought of mine and may be miles away from the cause.
John

 

[DenG1]

Many thanks, I will see how it is when I get home, anythings worth a try. Could be worse I suppose and have no heating at all. I have no problems with my heating engineer at all. Everything was done by the book when the new boiler was installed in January this year. He is local and popped in on his way home for a quick "listen" and did not charge, I'm trying to find out if this is something relatively simple but if it persists I will have to properly book him (he is servicing the boiler early in new year to ensure it remains under its 3 year guarantee) to sort it out. Many thanks again

 

[D_Hailsham]

In January we had a new boiler (Vaillant ecotec plus 428) fitted in our loft which replaced a baxi bermuda back boiler.

Why did you have such a large boiler installed? The largest Bermuda provided 16.85kW and your 428 provides 28kW.