hot water coming out cold water taps

bluff_ugi · 19 May 2006

Does anybody know why I have hot water coming out my cold water taps in my bathroom? (The kitchen is ok). The water is also really hot.

I turned the hot water supply off about a week ago to replace a tap and now this has happened. Any idea how to fix it?

(I can also hear the water in my hot water tank boiling! Can this be related as it never used to do this?)

jobloggs · 19 May 2006

Some details of type of system would help.

You could have a failed thermostat on an immersion heater causing hot cylinder to boil. Switch of immersion heater to check.

Have you a cold water storage tank in loft. Feel it. Is it cold?

bluff_ugi · 19 May 2006

I have a tank in the loft and it is hot!

I have a potterton suprima 50L boiler if that helps.

Any ideas?

Biggles.. · 19 May 2006

Could be failed cylinder stat or motorised valve allowing the water in the cylinder to boil over back into the cold water storage tank, thus making hot water at hot tap boiling and tank in loft hot. kitchen cold taps ok because fed from cold water main. Bathroom cold taps sound like they are low pressure so are fed from the tank in the loft which as you have described is now boiling hot instead of cold.
Lee

chrishutt · 19 May 2006

lcgs said:
Could be failed cylinder stat or motorised valve allowing the water in the cylinder to boil

How would the cylinder water "boil" if the boiler temperature was limited to say 80°C? The boiling of the cylinder water must be due to a failed stat in the immersion heater, which has been left switched on (as jobloggs has already said).

ChrisR · 19 May 2006

Dead dangerous:
http://news.bbc.co.uk/1/hi/england/cornwall/3035606.stm

bluff_ugi · 22 May 2006

Thanks to all who gave their advise...I changed the thermostat on the immersion heater and hey presto...its all back to normal again.

Thanks again...

ChrisR · 22 May 2006

Good! The new type stats are much safer than the oldies.

Agile · 22 May 2006

In view of the dangers of failure of plastic storage cisterns may I suggest that if yours is plastic that you carefully inspect it all round to ensure that it has not deformed as a result of being heated up!

Tony

bluff_ugi · 22 May 2006

OK - I'll check it over...

Thanks.

avarils · 12 Nov 2009

Hi,

It's my first post here and I could really do with some advice. I have exactly the same problem with hot water coming out of my cold water taps. The water is also boiling in the tank in the loft.

Reading the advice here I've changed the thermostat on the cylinder tank (and set the new one to 60 degrees)but its still doing the same thing (water boiling etc).

When I touch a piece of exposed metal on the tank where the thermostat is clamped on, it actually fells quite cool, so I'm not surprised it keeps asking for water to be heated. Could there be an air bubble in the tank causing this and if so how do I remove it?

I've switched off the immersion heater while this problem exists to prevent damage etc...

Any help would be greatly appreciated!

thanks

kevindgas · 12 Nov 2009

DO NOT RUN BOTH the boiler and the immersion as this will cause the overheating you describe
make sure that you and your family are not sleeping under the tanks in the loft until this is checked by a very competent engineer.

Whitespirit66 · 12 Nov 2009

avarils said:
I've changed the thermostat on the cylinder tank (and set the new one to 60 degrees)but its still doing the same thing (water boiling etc).

Do you mean that you have changed the thermostat that is strapped to the outside of the cylinder?

If you have, you have changed the wrong one. The thermostat that controls the immersion heater is under the cover of the element itself (where the supply wires go in)

Isolate the elec. supply to the immersion element, and remove the element cover/cap. Inside you will see a part with a small dial and numbers on. Remove the wires from it, withdraw it from the element, and replace with one of the same type.

Goldspoon · 12 Nov 2009

avarils said:
Hi,

Reading the advice here I've changed the thermostat on the cylinder tank (and set the new one to 60 degrees)but its still doing the same thing (water boiling etc).

thanks

There are TWO thermostats on your cylinder. You have changed one of them and probably not the one causing the problem.

No. 1 thermostat is strapped to your cylinder and controls when the boiler comes on and off to heat the water. I think you have changed this.

No. 2 is built into your immersion heater (is likely under a metal cap so you cannot see it). An immersion heater is an electrical device that protrudes, stick-like, into the top of your cylinder. Probably it is this device's thermostat that has failed and is boiling the water (when your immersion is switched on it keeps heating and heating until the water boils and rises into the loft tank).

Goldspoon · 12 Nov 2009

Bah... beaten to it

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

hot water coming out cold water taps

Goldspoon

Goldspoon

Similar threads