Noisy central heating pipes

[MikeN]

Hi,
My central heating system is quite noisy at times. The noise is a whooshing-type noise and seems to be present throughout the pipes and radiators. The boiler is a Baxi combi boiler and is fairly new (less than a year old). General info about the system:

• The pipes start off at 22mm then reduce to 15mm near the radiators.
• The noise isnt there all the time.
• If I turn the hot water tap on it goes away (Baxi did change the diverter valve but it didnt help and they said the noise is within the heating system rather than the boiler??)
• If I adjust the TRVs it can change the pitch of the noise but I'm not sure if this just because it is changing how the noise is transmitted through the radiator.
• The pressure on the boiler is set within the specified zone on the dial.
• The house is just a 3 bed semi with typical size radiators and as far as I'm aware nothing unusual about the system.

After doing some internet research I think it may be caused by the velocity of the water, but I'm not sure - does this seem reasonable? If so what is the cure for this? Or could it be something else causing it?

Any help would be much appreciated. Many thanks - Mike

 

[technoallah]

Hi Mike,

I've got exactly the same problem, with a 8month old Baxi Duo-Tec 24 installation. Adjusting the TRV's also changes the noise or velocity of the water. It's actually sounds like a running tap, when I have the radiator on.

It would be great if someone could identify this problem.

 

[ferret]

Hi guys , check that the lockshield valves are fully open (the other end from the trv,s) as this can cause the noise , because the flow is being restricted , these valves are used for balancing purposes and a new install should not need balancing if it is designed properly , you will need a spanner to do this , remove the cap and adjust fully out anti clockwise , then back a tad , the noise will go away with a tap running as the heating water is diverted to heat up the hot water

 

[dontknowitall]

Wonder tip to learn! I've a radiator in my house that whistles occasionally and a quick twist with the TRV solves the problem. But a fiddle with the lockshield might be the permanent cure I need!

 

[technoallah]

Sorry bit of a late reply... no luck of the lockshields as they're open.

Well I had the 2nd engineer hired by the installer come out and listen to noise. He attributed to the noise/whoosing down to the boiler (Baxi Duo-tec Combi 24kW) being to powerful/giving to much pressure for the flat. He recommended adding more radiators (I've got 4), to ease the pressure.

I phoned Baxi and they said that's irrelevant and suggested reducing the TRVs down to a minimum setting. However when I do this say below 4 or 3 for example, the flow totally cuts out of the radiator and it goes cold. One of the radiators closet to the loop point is really bad to the extent that I turn it off at the TRV it's actually louder than it is on.

My plumber had a look at the underfloor piping and said there's some shoddy bends leading in and out to the loop point, if this has anything to do with it.

Any help would be great appreciated...at the end of my tether here, installation was done in Jan 2010 and it's still not working right, feel like I'm being given the runaround by the installer.

Thanks

G

 

[Billy Bob Bob]

it has probably nothing to do with the boiler, its numatic noise caused by the trvs/pipework/locksheilds but it may also be that the boiler has a 6 mtr pump fitted this may make a noise if its on a small system but i doubt it