Vented hot water tank overflowing

[Poppygirl]

My vented hot water tank is overflowing into the expansion tank in the attic, which, as a consequence is overflowing through the overflow pipe to the outside. Only recently had the ballcock in the cold water tank replaced. Hope there is a quick fix for this! Please assume I am a complete idiot and make explanations as simple as possible!! Thanks!!

 

[JohnD]

did this start happening after you had a new mixer tap installed, especially a kitchen mixer with a single joystick lever that goes up, down and sideways?

Or a shower mixer where it is difficult to maintain a steady temperature?

 

[Poppygirl]

Sorry no, it started the day before yesterday. Nothing changed plumbing wise, although the water pressure has reduced slightly. Thanks for your response,

 

[dal5band]

What JohnD was implying is some mixer taps let the cold water run up the hot pipe thus over filling the hot tank. This happens if you have mains cold pressure but low pressre hot at a mixer tap or shower.

 

[Burnerman]

Just to clarify things, its definitely the smaller of the two loft tanks that's giving the problem, correct?
John

 

[dilalio]

@Poppygirl have you been up in the loft and checked both ball valves are shutting off?

 

[oldbutnotdead]

While you are in the loft, check that the new ball valve has been adjusted so the water level in the tank is well below the overflow (there should be a scum line to work to) and that the new valve isn't leaking and actually shuts off properly

 

[HERTS P&D]

Looks like Poppy has gone to the pub.

Andy

 

[dilalio]

Looks like Poppy has gone to the pub.

Andy

Which is exactly where I'm thinking of heading... Been for a lovely walk with the dog, until I got shouted at by an attention-seeking fishery bailiff, who obviously didn't know how to "talk", that got me wound up so he got to know exactly how I feel about such to$$ers... Now I need a beer

BTW: I also fish there!

 

[JohnD]

My vented hot water tank is overflowing

how do you know it is coming from the hot water cylinder (it's not a tank)?

is it surprisingly hot?

does it happen all day, or mostly overnight?

 

[Poppygirl]

Hi wasn't in the pub!!
The overflowing has stopped now and hasn't happened for at least 24 hrs. Yes, I checked both stopcocks and they both shut off fine. The expansion tank is now nice and cool.
Thank you all for your kind help.

 

[HERTS P&D]

These problems never go away without being fixed.

Andy