Immersion heater / cylinder

[Adrian R]

Hi,

I'm after some help with an immersion heater. I've recently moved into a flat, and the hot water cylinder has started making some disturbing sounds. The system is relatively quiet (other than a few knocking sounds) when it is heating up... but it makes a hell of a lot of noise when I go to use the hot water!

When I turn on the hot water tap (either in the kitchen or the bathroom) for more than about 4 seconds, the tank makes a kind of vibrating/resonating type of sound. This continues for a while, then fades away. It doesn't happen *every* time I use the taps... but it is quite a loud sound, it even shakes the floor slightly!

What is a little odd is that this sound doesn't occur if I use the shower - even though the shower seems to feed straight from the immersion tank.

I've tried draining the tank (turning all the hot water taps on for an hour) and then letting the tank re-fill.. this seemed to make the problem worse. I'm not sure if its relevant, but the property wasn't lived in for about 6 months before I moved in.

Does anybody have any ideas as to what this could be?

Thanks in advance,

AdrianR

[IMM]

Sound like air trapped. Also check that pipes are not loose and are well clipped.

[John]

Firstly it is extremely unlikely you immersion has anything to do with the problem Your ball float valve in the cold water storage header tank supplying the cylinder is most likely cause and groans when the valve is passing water. Its quiet when the shower is on because you are also drawing cold water and relieving the pressure. Cheap 1st line of attack is renew this ball valve. Also check your cold pipe to this valve is properly secured. If you don't have a service isolator on the ball valve fit one while you are about it.

[Set Square]

When you run a hot tap, cold water runs from the header tank (in the loft?) into the hot tank to "push out" the hot water. This causes the level to drop in the header tank - whereupon the ball valve opens to replenish it.

My guess is that you've got a noise ball valve in the header tank. You can test this by temporarily tying up the ball valve so it can't open and running a hot tap. If the problem is still there, it ain't the ball valve - but if this fixes the problem, it probably is.

You may be able to cure it by dismantling the ball valve and cleaning all the moving parts - or you may need to replace it.

[Adrian R]

Thanks for everybdoys input on this one - it was indeed the ball valve causing the problem, which I've now managed to remedy!

Adrian.