DIY Doctor UK DIY Forums

Hi, a couple of months ago I moved into a new house, which is 7 years old. It has a central heating system with separate heating/water controls (not a combi boiler, which is what I was used to).

I've noticed the last couple of nights that the water tank has been making bubbling noises through the night, when it's not switched on. It's set to come on at 6am but it starts to quietly bubble away from about 2am, then gets louder and goes on til about 5am!

What is it doing? And how is it doing it??? Is this normal/safe? Could it be that when the temperature outside reaches freezing (as it probably has done the last few nights), it switches itself on? (I've no idea if this is a feature of my system). Or is something potentially dangerous going on?

Also, if it is switching itself on, and staying on for hours at a time, it's going to cost me a mint...

Can anyone help, as it's driving me mad - its right above my bed and makes it really hard to sleep as it becomes noisy enough to be very distracting.

Thanks :o)

Does it have an immersion heater ? if it does the stat could be faulty.

Have you checked the water at the hot taps when this noise happens ? it it very hot ?


htg

Not that I know of. I've not spotted any switches anywhere for an immersion heater.

my central heating system keeps the hot water topped up at all times, even when the heating is switched off, so if anyone has recently run off any hot water, eg washed their hands or had a shower then the hot water automatically tops up even if the heating is off.

I'll go with Htg's explanation here. Heating after 1am can be normal as the low tariff Economy 7 kicks in and the element automatically switches on.

Some systems have the immersion switch downstairs somewhere in the kitchen so you could turn it on without having to go upstairs. Look for the element in the top of the tank and follow the cable to find the switch.