overflow running

You seem to have carried out all the essential checks.

I'm not familiar with this kind of system, but presume the hot taps are supplied from the cylinder - which in turn is fed from the cold storage tank, so under gravity pressure - but the cold taps are fed direct from the mains?

If so, and the hot cylinder has not other connection to it (no wet heating coil), then it must surely be cold mains water doing as you say - leaking in to the hot cylinder and hence up to the CWS (does the water up there feel warmer when this overflowing happens?)

How much water comes out the overflow - I'm guessing chust a trickle?

Anyhoo, I can only think it's a mixer tap somewhere - some device that shares the hot and cold.

You've replaced all the taps you say - silly Q: are there isolating valves on the pipes to these taps (cough - as there should be)? If so, turn the cold one off on each mixer tap in turn and see how that affects the situation - hopefully you'll find the culprit.

How is your washing machine plumed in? You don't have a 'cold feed' machine which someone has used a hot/cold tee on have you? (You can get these for the opposite reason - to supply both the hot and cold inlest of a W/M from only the cold supply - I wonder if some twit has fitted this t';other way around?

So, Qs:

1) Are hot taps from cylinder and cold from mains?
2) Is W/M connected ok?
3) Any 'wet system' heating coil in the hot cylinder?
4) Have isolating valves been fitted to your new tap supplies?

Can't think of anything else...

 

Hi
You may have what's called a thermal store,

The water in the cylinder is fed from the header tank, and heated via, day / night rate emmersion elements,

A coil is fitted in the cylinder and is mains fed, the therma mass heats the coil and gives hot water at mains pressure

If the coil develops a leak, or will start to fill the header tank, this would be constant,

So,... It may be the ball valve is set too high to allow the water to expand in the thermal store, and is causing the intermittent overflow,

Regards
Peter

 

Hi
The coil is part of the cylinder, if you look carefully and figure out the pipe that supply's the cold in and hot out, there is often a blending vale fitted?

If not I may have assumed wrong and it's not a thermal store

Regards
Peter

 

Hmm, good point.

Dave, can you post a photo of the cylinder? (Set your camera to 3MP so's the pic comes out at less than 2MP - which is what you need for this forum.)

As for it being the taps, I can't see it happening unless the taps are actually turned on!

Unless you have one of these thermostatic blender types with the blender/mixer under the bath?