Leaking over flow pipe

dwill1503

We have had a leaking over flow pipe for several months. We have a cold tank in the loft & a hot Emersion tank on the 1st floor. The emersion has had a new thermostat & the ball valve has been changed in the cold tank.

There is no timer on the hot tank but we just turn it on & off. The over flow still leaks even if the hot tank has been off. It is very often hot water that is leaking out of the over flow. Sometimes if its leaking & we turn on a hot tap to try to release some water, it starts streaming out really fast out of the over flow, with hot water.

One morning last week at 5am, we woke up to what sounded like flooding, to find the over flow spraying out so fast it reached the end of the path, clearing the snow. We had to turn the water off at the mains to stop it.

Has anyone experienced this? We've had plumbers check it & they are all at a loss.

We do have terrible hot water pressure upstairs (so bad we don't use the shower at home) & one plumber has suggested removing the cold tank & replacing with a pressurised system (£330)
But, we are hesitant about doing anything until we've sorted the leak.

firefox1956

If you have a central heating pump try turning the speed down.
They are usually 3 speed.
HTH

dwill1503

We don't have central heating. We have a vented hot air system.

Seronera

I don't have the answer, but I have posted the problem in 'another place' where some clever people inhabit and I'd hoping one of them can come up with a response that makes sense. Mind you they can take the pee summat rotten as well...:D

I shall return if I get a reply I can repeat..;)

Seronera

dwill........one question. Do you have any mixer taps?

Zandoni

Check that the outlet from your Hot Water tank expansion pipe does not dip into the water in the cold tank in the loft.

Seronera

Zandoni wrote: »

Check that the outlet from your Hot Water tank expansion pipe does not dip into the water in the cold tank in the loft.

Its not that. The shower is the clue 😀

bambibashercol

Passing mixer tap would be my best guess without seeing the job in person.

Seronera

Its got to be that hasn't it.

My bet is that the shower valve is passing cold mains water to the hot and going back up to the tank. It could be that or a mixer tap passing cold water across or a last, but distant possibility is that on a hot and cold fill washing machine (rare these days) one of the inlet solenoids has failed.

dwill1503

we have a mixer tap in the kitchen (where pressure seems fine). the bath has a mixer tap but not a bath/shower mixer. the shower comes straight out of the wall - the cold pressure is fine, the hot is terrible. It seems the pipes to the shower go under the bath & up. could the poor pressure and leak be connected then?

Seronera

dwill1503 wrote: »

we have a mixer tap in the kitchen (where pressure seems fine). the bath has a mixer tap but not a bath/shower mixer. the shower comes straight out of the wall - the cold pressure is fine, the hot is terrible. It seems the pipes to the shower go under the bath & up. could the poor pressure and leak be connected then?

Well yes. What we think is happening is that one...or more..of your mixer taps..and/or the shower valve is not sealing the cold from the hot properly. As cold mains pressure is much higher it forces itself into the hot side. We call that 'passing' and it forces its way up the hot supply and fills your tank which then has to overflow....and thats your leak.

Also because it is forcing its way up in the face of lesser hot water pressure the hot water pressure reduces...hence your poor hot water. You need to find which is doing it by a process of elimination. There will be a main culprit, but potentially any mixing device..shower or tap can do it. From what you say the shower would be my first port of call as that is displaying the symptoms you'd expect.

If you have a water meter it is costing you as well. If your shower supply pipes..both hot and cold...have isolator valves on then shut them off and see if the leak lessens and stops. Just turning the shower off on the valve may not be enough to test it properly. If not then you have to repeat this for each mixer tap, which is a plumbing job really.