Hot water in cold water storage tank

[stevie-c]

My cold water storage tank feeds the hot water cylinder and also a shower with a pump. On several occassions the shower has been too hot to use. My initial reaction was that the shower was faulty but decided to do a bit of diy investigating and discovered that the cold water storage tank contained very warm water. It appears that heat is tracking back up the feed pipe from the hot water cylinder as this pipe is hot.
Is this possible? If so what can be done?

 

[kevplumb]

would think the vent is blocked or the coil in the cylinder is leaking

 

[stevie-c]

How do you test for either of these possibilities?

 

[PEDANTICVINDICTIVEMAN]

I should find out why the water is so hot to start with, faulty immersion heater stat or boiler stat faulty or to high check the vent pipe over the tank hasn't drooped and got immersed in the water as this causes gravity circulation and puts hot water into the feed tank.

 

[stevie-c]

There is no imersion heater. The hot water cylinder is controled via a cylinder stat set to 60 degrees and appears to be working fine. The hot water flow from the top of the cylinder goes horizontal for a couple of feet before going vertcally down. The vent pipe is connected to the horizontal part of the pipe and goes vertically up to the header tank.

 

[kevplumb]

pedantic posted on the wrong thread (he he he )
would still go with the vent

 

[brumylad]

This can be really dangerous, the tank can soften and colapse the hot water which comes throegh the ceiling has killed people! Honest!.

Get a pro in to sort it asap. Don't use the hot water in the mean time and check it stops getting hot.

Don't sleep under the hot water storage cistern in case it colapses.

 

[stevie-c]

My guess is that it is the vent. I drained down the cold water storage tank and turned off the mains feed to it to see if it would backfill from the cylinder. It didn't, so I don't think the coil is damaged in the cylinder. The vent pipe is warm only for an inch or two from the connection with hot water supply. Would you normally expect the vent pipe to be warm all the way to the cold water tank?

 

[Bahco]

Has the vent pipe been installed properly?
To prevent parasitic circulation the vent should start horizontally a certain distance (I believe it is 450mm ) from the top of the cylinder.
Could be the origin of your problem

 

[kevplumb]

oooh who has had the textbooks out then

 

[PEDANTICVINDICTIVEMAN]

Eh, what, cough cough, er, it's my neice you understand, told her not to sit on my knee, cough cough splutter, what day is it

 

[kevplumb]

you been at the solvent again
sniff it dont drink it even if it is your (neice )it wont work if you drink it

 

[shaneo]

My cold water storage tank feeds the hot water cylinder and also a shower with a pump. On several occassions the shower has been too hot to use. My initial reaction was that the shower was faulty but decided to do a bit of diy investigating and discovered that the cold water storage tank contained very warm water. It appears that heat is tracking back up the feed pipe from the hot water cylinder as this pipe is hot.
Is this possible? If so what can be done?

if your heating header tank is in higher position, than the vent for the cold water storage, and u are finding that the heating ball valve is filling every so often then u know its the cylinder
if it was the vent it would have always had this prob