Loft tanks

[shewolf]

Hi everyone

I am new to this site and have a question

A month or so ago, a plumber changed over two water tanks in my loft, replacing old ones with new, lidded and lagged plastic ones.

He also moved some of the piping around to make it neater (it was a real rats maze up there!!.

In addition to this he replaced my hot water tank with a new, bigger vented cylinder.

Since all this, every time the pump fires up there are some alarming banging and thumping noises which appear to be coming from within the radiators. I have been into the loft and cannot hear anything there.

I have also been bleeding radiators like its going out of fashion...no success.

Any ideas?....the heating and hot water all seems to be working OK...it's just the horrendous banging noises.

Thanks for any help.

 

[ChrisR]

You shouldn't have to bleed anything after the first day or two. No inhibitor added?? Pipework design/alterations could be a cause of noise as well as excess air. Poor fixing of the pipes could cause noise too.

 

[shewolf]

Thanks ChrisR

He installed a non-return valve but I do not know about an inhibitor.

What does an inhibitor do? (she asked stupidly)

 

[IanDB]

Inhibitor prevents corrosion inside the system. It stops the water reacting with the pipe work and radiators. Without it you will get an increase in sludge in the system and a build up of gas which has to be bled off.

It also appears to improve the water flow through the system but why this is I'm not too sure.

It is a must for heating systems. There should be a label saying when it was done as it should be replaced every few years.

 

[peter anderson]

Possible causes of noise in radiator:

1) Thermostatic radiator valve (TRV) on every radiator and no bolier interlock facility : one or two radiators shouldn't have a TRV fitted on them. Fit automatic bypass and room thermostat.

2) Water hammer caused by radiator valve being incorrectly fitted opposing water flow: replace or resite valve, ensure dirction arrow marked on the valve body is in the direction of the water flow.

3) Flow noise: decrease the pump speed

4) Air in system : vent radiators

5) Expansion creaks: Stress on radiator brackets: insert felt between pipe clips
and between metal contacts

6) Radiator is rattling on brackets: refit radiator on wall

7) Clatter at radiator: De-scale boiler and flush and protect system with inhibitor

If you find the problem is caused by one of the above or another I would be grateful if you could post a message telling me what it was

Thanks

 

[shewolf]

Peter

working on it - will post answer

Many thanks

Shewolf

 

[shewolf]

It appears that the problem is that the water cannot get out of the boiler around the system quickly enough and is "kettling" inside it.

................it is literally boiling in the boiler.

This is happening because the boiler, being new, is very efficient and the non-return valve put in by my plumber is preventing enough water from getting around the system quickly enough (if u see what I mean).

Everything else he did was great and is working fine...so he has turned the boiler down a little to see if that cures the noise although this morning it is still rattling away!

 

[peter anderson]

Thats interesting shewolf because in your first post you said that the noises were coming from the radiators? So is the noise coming from the boiler as well?

 

[shewolf]

Well I THOUGHT the noise was there but I guess it must have been an echo running through the radiators??

But when we both listened to the boiler last evening the plumber was convinced that it was in the boiler, especially as he took the front of the fire off and heard the kettling going on......he said.

Anyway I've now got to wait and see what happens.

Oh well!!

 

[peter anderson]

I don't know anything about boilers but it seems a bit weird that the bolier is kettling because 1) it is new and so efficient 2) the plumber put in a non return valve. Is putting in a non-return valve not standard practice then?

 

[oilman]

I came across a similar noise which I cured by turning one of the gate valves on the pump half a turn. That stopped the banging and rattling.

 

[billy bob]

Why has a non-return valve been fitted, there is normally no need for these to be installed

 

[billy bob]

You say you have been bleeding the radiators , are you getting a lot of air in the system, if you are the vent and cold feed arrangement may be incorrect, and air is been pulled in