Hot water tank starts bubbling

continualdiamond

I can't describe it any other way in that when the hot water is on at the main give it a couple of hours and then it starts bubbling and making a really loud noise. As if like when you're boiling water in a pan, telling you enough is enough and to turn it off.

It basically means i need to turn the hot water on when i am home to heat up enough water for baths or hot water from the taps etc. Then once i hear it start bubbling turn it off and again we got through the same cycle the next night etc.

Shower is separate and always has hot water.

What is it and is it dangerous? It is fixable and is it expensive?

Have put up with it for awhile now, seems ages that its been doing it.

ariba10

It would help if you told us how the water is heated.

Gas?, Elect?, Coal? Central heating?.

27col

I assume that you are talking about an immersion heater. If so then it sounds as if the thermostat has gone. This allows the heater to go on heating the water out of control. The sound that you hear is indeed, the sound of the water getting very hot. The replacement of the thermostat is a simple job and should not cost much. Think of it as a large electric kettle that will not switch off. It could be dangerous in that the very high temperature of the water could severely scald someone who was not aware of the problem. Best get it sorted as soon as possible.

JoJoB

Yes, the thermostat is most likely not working. Until you get it fixed can't you put the immersion on a timer so it heats up the tank and then clicks off? Did you say the bubbling started after a couple of hours? If so it doesn't need to be on for that long really. 30-40 minutes should be enough to heat the tank up.

continualdiamond

I have no idea how the water is heated cos im from Australia and have no idea how it all works over here re hot water tanks and central heating because hot water tanks are outside in Australia and central heating doesn't exist back home.

Basically in the spare room in 1 ventilated cupboard is the boiler, in the next cupboard is a big tank at the bottom, a shelf where i store towels and then a black box at the top where i assume the water is, because that is where the noise comes from. Inside this cupboard is a switch that i switch on/off just for the hot water tank. Sometimes it can be on for 1 - 2 but then i find the hot water lasts maybe 2 evenings if baths are run. Like i said the shower isn't affected and i thought for the time the hot water tank is on it really isn't generating enough hot water.

In the cupboard with the boiler is a timer i think, i have never tried to use it.

A thermostat is on the wall in the square, i say square because it is that, the bathroom and 2 bedrooms come off this area.

The thermostat is actually on the wall that behind it is the hot water tank in the spare room.

I thought this thermostat controlled the boiler though as i turn this on/off to make the boiler come on/off, however i think it is in the wrong place as the central heating will not come on unless at the max temp. So not very cost effective cos when you get too hot you cannot turn the temp down without the boiler turning off completely.

I hope this is all making sense to people who know about this kind of stuff, cos i know nothing about what i should be doing.

ariba10

I think it would be better for you if you asked someone local to have a look at it.

continualdiamond

I will, but problem is as soon as i mention i know nothing about this sort of thing i will probably get told a load of rubbish, scaring me into paying more than is needed to fix it.

Which is why i came here first to try and get some understanding of it all. I appreciate i won't know all the details, but just the basics of what does what would help.

ariba10

Do you have a friend, workmate or neighbour who might be able to help?

googler

Try posting the question in the plumbing and/or heating section at

www.diynot.co.uk

vaio

All guess work but my thoughts……..

It sounds like the thermostat has failed. The lower tank is the one that is heated, the black one up high is the feed/expansion tank

Look at it and you’ll see a wire coming from the wall to the tank, if that wire ends up at a circular boss maybe 75mm diameter and 50mm high then you have an electric immersion heater and the internal thermostat has failed. If the wire ends up at a plastic box maybe 50mm square with a temperature adjuster on the front then your water is heated by the boiler and your tank thermostat has failed.

Either is easy to change with a technical difficulty rating about the same as wiring a 3 pin plug.

Mains power off, remove cover/strap, make little drawing of where wires go them remove them from the thermostat, off to your local screwfix and buy a like for like replacement, refit the wires/cover/strap and the job is done.

If you don’t have the required plug wiring skills at least you’ll be able to describe the problem and probable solution to the local plumber when you ring him to arrange a visit. When he’s there you can get him to show you how the heating works.

All this is assuming you own the property, if you are renting just ring your landlord