noise in pipes/radiators

[PAINTERJHD]

Hi could anyone tell me if i need a pressure reducing valve,it is to stop the noise in the pipes or rads well some of them it sounds like a kettle that has not quite boiled. The boiler is a Greenstar WB 35CDI all rads have trvs but i have taken the head off the one in the bathroom,it is running 13 rads on three floors,any help would be much appreciated thank you.

 

[Slugbabydotcom]

Hi could anyone tell me if i need a pressure reducing valve

A PRV wont do it. These are meant for cold water supplies.
Try the ABV as on your previous topic but first turn all your rads off bar one. Open your next rad and close the first one. Work your way around the system to clear any trapped air individually from each rad circuit.

If that doesnt work then read this and post back. It is better to keep your posts in one place so that we can track how you are doing.

At this stage it is possible that you have one of several boiler problems we need as much info as possible to help you figure it out.
Is your system pressure stable ?
Can you describe the noises and where they are coming from?

 

[Bahco]

All rads have trvs .

Is there an auto bypass fitted

If not then your boiler will kettle if the trvs all close down

 

[Strachan]

Auto bypass is fitted on the boiler on the greenstar 35, apparantley the 35 can get the primary flow temperature above what certain makes of trv can handle. this makes a very distinctive noise. Read the manual for the boiler, i seem to remember that you can reduce the maximum primary flow temperature. Worth a shot.

 

[PAINTERJHD]

Hi thanks for all your replys,the pressure in the system is stable,dont think there are any leaks. There is no auto bypass fitted but i am using the bathroom rad with both valves fully open the trv head has been removed. The noise is a bit like the water going through at high pressure for want of a better description, i have looked at the manual and there is no mention of being able to adjust the flow temp of the primary circuit. If i partially shut the locksheild valve or the trv the noise stops but the trv is down to 2 on the scale and the locksheild valve is nearly closed,hope this helps in your diagnosis thank you all.

 

[Slugbabydotcom]

The flow temp of the heating circuit is controlled by the boiler stat.

Is it just your bathroom rad thats noisy?

If so what I would be inclined to do is drain down and look for a physical blockage in the area of the noise. Maybe someone got a bit happy with the ptfe tape!
If there was no joy there I would then look at the possibility of the integral bypass being blocked and consider fitting the additional ABV as you have already figured or perhaps fitting a by-pass at the connections to the furthest rad from the boiler with just an ordinary by-pass valve on it as they used to recommend on ferroli boilers. The latter is not 'by the book' but I think it would be the most effective.

 

[PAINTERJHD]

Thanks for your quick reply, no it is not just the bathroom rad that is noisy most of the others are as well except for the top floor (3rd floor). I will drain the system and check for blockages as you sugest, not quite sure as to what you mean about bypass on furthest rad from boiler,could you please explain how to go about fitting it please many thanks.

 

[Slugbabydotcom]

A bypass is simply a pipe that runs between the flow and return.
It does what it says on the tin and bypasses the circuit to the rads
By fitting a bypass at a distance from a boiler you reduce the risk of the furthest rads not getting their share of water.
This bypass should take the strain from the nearer rads which are getting too much flow. When you get too much flow through a small opening [your trvs] this can result in noise.

An ABV closer to the boiler will do the same job but I have noticed they too can be noisy in operation also they have to have a bit of pressure, ok its only 0.1 bar built up before they operate. I feel that a permanently open bypass at the far end of the system would be a better option. Ferroli agree with me or at least they did. If you go to their website and look up the manuals of one of their older boilers you will see that this is the method they advocate.

Just had a quick look and the way to get there once on the ferroli.co.uk site is by clicking support, domestic, technical, download [at the bottom], non current installation manuals, On page 10 of the .pdf file it says

The bypass should
be fitted as far as possible from the boiler if thermostatic radiator valves are fitted throughout.

There is a picture of it on page 11

 

[PAINTERJHD]

Thanks for your advice slugbabydotcom,i will fit the bypass at the furthest rad on the top floor, just a pipe joining the flow and return and not a abv is that right. Have looked on the site you refered me to, not sure if the bypass was a valve or just a pipe,please could you put me right, many thanks.

 

[PAINTERJHD]

Hi this is additional to the last post,i have just pulled up some floorboards in the bathroom, and found the rad has got service valves on the flow and return to the rad could this be causing the noise ?

 

[uug197h]

try turning the pump down (theres 3 settings) this will reduce the speed of the flow

 

[doitall]

Dare I ask if they have been connected with microbore pipe (8-10mm)

 

[PAINTERJHD]

Thanks for the replys, i cant alter the pump speed on this model, and no it is not connected to microbore