Help with noisy hot water heating loop

[marc1977]

Hi,

I have a sealed S plan system which is noisy BUT only when i have the hot water on alone. If i have the central heating and the hot water on together there is no noise but as soon as i switch the central heating off it sounds as if there is air or something moving inside the pipes (sounds a bit like a marble moving around the pipe!).

I have a separate issue where I am getting a small amount of air in the highest rad (it needs bleeding for about 2-3 seconds each week even though i can find absolutely no leaks and ive checked everywhere!).

Any ideas on either issue?

 

[ShaunCorbs]

Could be too much flow through the cylinder coil (does the noise sound like somthing is vibrating or is it more of a ting ting noise)

Second question do you have to top up the system pressure twice a week ish ?

 

[Last Plumber]

Is there an auto bypass on system and balancing valve to coil fitted ?

 

[marc1977]

Excellent, you both sound like you know what you're talking about!

1. The noise is like a Ting Ting, not vibration
2. Despite a very small leak the system pressure does not visibly seem to drop. I checked it when cold over a week or so and could not see a visibly change, it remained bang on 1 bar. (It obviously drops slightly if i bleed the radiator)

3. There is a bypass valve fitted.
4. There is also a balancing valve to the coil (i haven't touched this so not sure how open it is).

Thanks again

Marc

 

[ShaunCorbs]

Seems like you might need to put some more inhibitor in your system

The valve on the coil is it a red gate valve ?

 

[Last Plumber]

What type of Boiler ?
System Boiler or Regular Boiler (with external pump)?

 

[marc1977]

Shaun,

Yes, the valve is a red gate valve. I've recently put in some new inhibitor (and leak sealant) whilst removing a radiator to decorate - would this really make a differecne to the "tinging" noise?

Last Plumber,

Its a regular Worcester boiler with an external pump. (Its oil rather than gas as we live in the sticks but dont think this makes a difference.

 

[Last Plumber]

What speed is the pump on?

Has this just started ?

 

[ShaunCorbs]

Depends if you drained the whole system could be air trapped in the coil

 

[marc1977]

Shaun,

The system hasn't been drained recently so dont think its air trapped in the coil. There is manual an air oulet valve next to cylinder which i checked and no air in there. The tinging noise is coming from the pipes near the boiler that feed the coil

Last plumber,

The pump is on max speed setting - its a big house though with 15 radiators.

We moved into the house 6 months ago and as soon as we moved in i had the old 1 pipe system replaced with a 2 pipe system. The noise (and also a small amount of air somehow getting into the system) have been present since then. Unfortunately plumber who fitted the system has now moved and cant get hold of him.

 

[marc1977]

Whats weird is that:

a) the noise from pipes is only present when the hot water is on alone. As soon as i switch the central heating on it disappears?!

b) Its a pressured system with no visible leaks so how come i have to bleed one of the rads for 2-3 seconds every week?! I've also checked the expansion tank overflow and there is no water discharge from there.

 

[kris]

Is the noise only heard near the tank ?

 

[marc1977]

Kris,

No, the ting ting noise is coming from the 22mm pipes near the boiler. Sounds like air in them to me but this doesn't really make sense (see above)

 

[lame plumber]

turn the circ pump down a notch and try adjusting the bypass as well if it only happens on hw it is probably down to too high circ rate on smaller circuit and just needs adjusting.

 

[townfanjon]

Excellent, you both sound like you know what you're talking about!



Marc

Forgive me Marc , I aint taking the pi** , Its the funniest thing I have heard today , YES they certainly do lol

 

[Last Plumber]

I agree with Lame.
You could try adjusting the Balancing valve a bit too on the cylinder coil.
Try half way open if it's 22mm

 

[marc1977]

Right, I have Rubbish the gate valve off slightly and it seems to have stopped the noise! Thank you all.

Anyone any idea on how i can be getting air into a sealed system but dont have a leak? only a small amount but its there...

 

[Last Plumber]

Right, I have **** the gate valve off slightly and it seems to have stopped the noise! Thank you all.

Anyone any idea on how i can be getting air into a sealed system but dont have a leak? only a small amount but its there...

It may not be air, it could be hydrogen !
By product of corrosion ?
Did you have rads changed when pipe work was changed to two pipe?

 

[marc1977]

Yeah all rads except 1 were changed. Ive tried setting the air on fire but didnt ignite!