hot water/heating overflow problems

[Keeeneo]

hi everyone, can any one help?
When my heating is off my overflow is running from the tank connected to the cylinder. When the heating is on, it stops overflowing. I have replaced the pump because it was hot to touch and also the motor in the valve for the same reason. Any ideas on what is causing the overflow to run now?

 

[seco services]

we've been here before haven't we with this problem ?

 

[Keeeneo]

Yes, was told by one plummer it was the pump as it was hot to touch, changed that and another one told me it was the motor in the valve as the casing was hot, changed that. Now i've been told its the cylinder tank by another plummer and another says it's the boiler. I just don't know who to believe or what to do next.

 

[seco services]

last time i remember telling you to isolate the mains stopcock and you said the problem stopped overflowing straight away.

am i right ?

 

[Keeeneo]

Yeah it stopped for about three days and then started again.

 

[seco services]

but if you shut your mains stopcock does it not overflow ?

only started again when your mains water was back on.

 

[Keeeneo]

continues to overflow, at a slow little trickle then when turned back on gushes for a while and then slows to a faster trickle now. Did stop first time, not anymore. even when I changed the pump and shut off all valves and turned off everything I could it still overflowed.

 

[seco services]

is it only continuing to overflow at a slow trickle because of the level of water still in the cws.
or your not fully closing the stopcock. shut stopcock and open kitchen cold tap.

if you lowered the water by an inch or so then left the mains off alnight the overflow would stop and the tank wouldn't fill no more.

i still say what i said before you have mains water bypassing to gravity hot through either a mixer tap or shower.
what mixer taps have you running on cold mains hot gravity ?
poss the kitchen mixer tap quite common for this.

 

[Keeeneo]

I have one mixer tap in the kitchen and a power shower in the bathroom.

 

[seco services]

can you isolate the kitchen tap overnight.

and what power shower is it ?
is it one with internal pump or pump next to the cylinder ?

doubt thats plumbed cold mains hot gravity.

 

[Keeeneo]

shower has pump inside i believe!

Don't know how to isolate kitchen tap. Will changing tap sort out the problem??

 

[seco services]

shower has pump inside i believe!

what make/model ?
if it's a power shower that looks like a electric shower on the wall then no it won't be that as that should be both gravity feeds.
then i would 100% say the kitchen mixer.

Will changing tap sort out the problem??

if it is the tap thats why i said isolate it over night.
has it no isolation valves in the pipework.

 

[Keeeneo]

all the pipework is hidden behind the kitchen units the only thing that is there is the mains stop cock tap.

 

[seco services]

all the pipework is hidden behind the kitchen units the only thing that is there is the mains stop cock tap.

well you'll have fun. thats where i would start.
it's def a cold water to gravity hot issue.

 

[Keeeneo]

cheers, i'll give it a go. Thanks for all your help and advice