Ideas please? Overflow running when bath is run

[surreytog]

The way this is acting is very strange.

We live in a top floor flat (3 storeys below us).

The overflow pipe outside starts running whenever we run a bath - sometimes it happens just after the bath is run, sometimes not until the bath is emptied.

I've tried switching off the cold water tap to make the overflow stop running once it has started - however, the strange thing is that this does not automatically work.... sometimes I have to keep jiggling it off and on until I can hear the water in the pipes stop.

Any ideas?

 

[seco services]

sounds like the tap is passing cold mains to hot gravity.
is the overflow from the plastic tank in the cupboard etc ?

 

[surreytog]

The overflow is in the cupboard, yes.

 

[ScottishGasMan]

Take it you have a mixer tap in the bath?

Is it possible that regardless of it being on or off when you jiggle it, it only stops when you keep the tap on either hot or cold, but when in the middle/mixing position the overflow runs?

If this seems to be the case then Id agree totaly with the above, chances are the cold water is mains pressure, and hot is off the tank, and the tap is passing causing mains to push into the tank then over filling it,

 

[surreytog]

Nope - it's not a mixer tap

 

[swidders]

One in a million longshot - I don't suppose the cold water valve is firing water towards the overflow pipe???

 

[Slugbabydotcom]

Number 2 of a million. Has this happened since a washing machine has been fitted? I have seen someone fit a Y piece the wrong way round so that the cold mains runs directly into the hot supply.
Number 3 of a million. I wonder if theres a thermostatic mixer valve that has a problem. Wrongly plumbed in or just plain faulty.

 

[Softus]

The way this is acting is very strange.

No it isn't.

The overflow pipe outside starts running whenever we run a bath - sometimes it happens just after the bath is run, sometimes not until the bath is emptied.

Well then, service or replace the float valve in the cold storage cistern.

I've tried switching off the cold water tap to make the overflow stop running once it has started - however, the strange thing is that this does not automatically work.... sometimes I have to keep jiggling it off and on until I can hear the water in the pipes stop.

Well then, service or replace the float valve in the cold storage cistern.

Any ideas?

Service or replace the float valve in the cold storage cistern.