Hot water tank/cold feed tank over flowing, please help..

[k4neb]

Hi there everyone

heating systems id the one thing i pretty much know nothing about, so i need your help.

i noticed on friday that my overflow from the cold feed tank on top of the hot water tank has started over flowing. the ball cock on the cold feed is fine and shuts off way before the water level reaches the over flow.

however the water level then continues to rise slowly and then starts to trickle out the overflow to outside.

if i listen very carefully i can here the cold water running, so it must be coming from somewhere??

it doesnt matter if the heating and hot water is on or off it still continues to fill up.

if i run the hot tap it drains down again. but then the process continues.

im aware of the hot water tank releasing the expanded hot water into the cold feed tank but as the boiler is not on and the water in the tank is not at all hot i dont think this is the case.

as i have said i know nothing about heating systems.

i have a little glowworm boiler that i think feeds the hot water tank thats about all i know.

heres a picture that might help.

green arrow - the cold feed, ball cock is fine.
red arrow - the overflow
pink arrow - pretty sure thats the hot water out
orange arrow - not really sure, water in?
blue arrow - coming from bottom of boiler which i think is whats filling up the cold feed tank on top.

there is also another pipe around the back that goes up to the cold feed tank that i believe vents the hot water tank into? this above the water level in the cold feed tank but nothing is coming out of it.

help and advise would be great please
also if you could explain in laymen’s terms, as technical words for stuff with it all will go right over my head

thanks in advance.

 

[picasso]

If you can hear water when everything is switched off then you probably have a passing shower valve or somewhere that the hot water and mains water meet, try isolating one thing at a time to pinpoint where the cold is passing into the hot supply.

 

[seco services]

If it's heated by a boiler have you another small tank somewhere ?

Poss the cylinder coil is pin holed.
Poss you are passing cold water to the hot through a mixer tap or shower.

 

[k4neb]

thanks for the quick replys.

yes i do have another smaller tank to the side that is fed by the same cold feed. this tank is working fine. see pic below

i have just turning off vales to see if i stop the top filling up, the only one that worked was the one that feeds the whole sytem. which is downstairs in the kitchen, pain in the rear.

i have a very big lacking of valves so isolating each part is basically not something that is possible.

after turning off the water in the kitchen and running a few taps when i turned the cold water back on again the boost in pressure has made the top cold feed tank fill up even quicker! and the sound of the water unning is louder, like the systern on the toilet filling up.

im guessing that maybe i might have pin holes in the coil inside the tank?? and the boost in pressure from turning the water off and on has made it worse?

 

[joe-90]

Christ! Don't trust those brackets and a couple of screws. Water is heavy.

 

[k4neb]

Christ! Don't trust those brackets and a couple of screws. Water is heavy.

thats how its been since i moved in. terrible isnt it.

good job that tank is only half full.

 

[picasso]

Its not the coil causing your problem its the mains water backfeeding into the hot supply.

 

[k4neb]

Its not the coil causing your problem its the mains water backfeeding into the hot supply.

so would this be a valve somewhere or something?

 

[joe-90]

A mixer shower would be the most likely cause.

 

[sooey]

There's an isolating valve on that pipe into the fortic. Have you shut that off to see if the water stops running?

 

[k4neb]

A mixer shower would be the most likely cause.

YES! that completely went over my head, but yes that was the cause.

i drew out a diagram on a piece of paper of my system as was confused as to how it could be back feeding.

but yes the shower mixer on the bath was the problem.

im happy now i know what it is.

thanks for the help everyone and the quick replys, much appreciated