Hot water in the cold water tank

[welder11]

I have been working in the loft and noted that the water in the cold water tank was quite warm. Can anyone suggest a reason for this?

Should I change the thermostat on the cylinder?

 

[seco services]

where is the warm water coing into the tank from ?
vent or the cold feed to the cylinder.

 

[welder11]

i believe it is coming from the hot water cylinder and spilling into the cold water tank

 

[JohnD]

THIS COULD BE VERY DANGEROUS

is it bubbling up from the vent pipe which comes out of the top of the cylinder, and bends over the top of the cold water tank? Doers this pipe dip into the water, or is there an air gap?

Is the cylinder heated by gas boiler or electric immersion heater? Have you got both? Are they both on?

is the cylinder, and the water from the hot tap, too hot to have you hand on?

is the immersion heater quite old (a photo would help)?

do you have children, elderly or disabled people in the house?

is there a room under the cold water tank or the cylinder? does anyone sleep there?

photos will help, especially of the top of the immersion heater
http://www.diynot.com/forums/viewtopic.php?t=129539

 

[welder11]

Posted: Mon Oct 25, 2010 9:07 pm Post Subject:

--------------------------------------------------------------------------------

THIS COULD BE VERY DANGEROUS

is it bubbling up from the vent pipe which comes out of the top of the cylinder, and bends over the top of the cold water tank? Doers this pipe dip into the water, or is there an air gap?
I will check this in the morning
Is the cylinder heated by gas boiler or electric immersion heater? Have you got both? Are they both on?
Both gas plus emersion only one at a time
is the cylinder, and the water from the hot tap, too hot to have you hand on? The water was orginally very hot and was adjusted at the tank thermostat that seemed to work

is the immersion heater quite old (a photo would help)?

I will check

do you have children, elderly or disabled people in the house?
no

is there a room under the cold water tank or the cylinder? does anyone sleep there?

Yes living room no sleeping, the water is on a timer
photos will help, especially of the top of the immersion heater

tomorrow

 

[JohnD]

OK. Best to turn off the boiler and immersion heater overnight. There is a risk that if it continues to overheat, especially overnight when taps not being run, the tank could give way and scalding water pour through the ceiling. This has been known to happen, causing the death of a child sleeping underneath.

Also, children and old or disabled people have had very bad scalds caused by being put into a bath of overheated water. Fit young people can quickly jump out,

I am not making any of this up. Luckily it is very rare and modern designs reduce the risk with the latest heaters.

 

[welder11]

Thanks fro the update I am going up to the house this morning (it is my Son's) I thought of changing the cylinder therm. and getting in an Heating engineer to check the system out.

 

[JohnD]

a photo of the top of the immersion heater will be helpful. Modern heaters have an overheat cutout as an extra safety measure. It is very difficult to get an old immersion heater out, but an experienced plumber should be able to do it without damaging the cylinder (the copper shell is paper-thin and easily creased or torn)

 

[welder11]

I have been up into the loft and no sign of the water flowing into the tank. The tank is also clean therefore I assume that the clynder in sound. The syptoms have now been clarified a little further the tank overflows to the drain when the hot water is used. I tried this several time no action. I did note that the morotosied valve on the tank was sticking on hot water even when switched to CH. I moved this with the turn and it then worked but seems to be intermittent.

The pipe from the top of the tank did get warm but nothing was ejected into the cold water. Next step in to change the motorised valve and possibly the therm on the clyynder?