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Got a pouring overflow from the cold waters storage tank, changed the ball valve and it is not filling from there,when it is full it is filling from the cold water outlet of the tank, figured the water was coming in from the rising main and getting past the sink mixer and into the hot and into the cylinder and pushing up the hot water into the cold water storage tank, fitted a single check valve to the hot side of the kitchen sink mixer and shower mixer, lasted seven weeks now doing it again, just fitted a pressure reducing valve to the incoming mains and taken it down from 3 bar to 1 bar, Central heating is gravity fed and the storage tank is not continually filling so i figure the water is not leaking into the cylinder internally and pushing that way, what on earth could it be I have never come across anything like this, totally stumped, help.

Pouring overflow, not an easy fix or is it, im stumped.

It's normally coming from a mixer tap/valve somewhere......

Last time I had a similar problem to deal with, it was in a pub :) .

It turned out to be a glass washing machine in the bar.

Hi,

The last time I saw this problem was in a residential home that had temperature check valves fitted to control the water temperature to the sinks.

The valve are connected to the hot and cold supplies to obtain the correct temp before going to the hot tap.

When a valve failed it allowed cold water at mains pressure to force itself back up the supply pipe from the tank in the loft......

This could be seen and felt in the tank as the water back-flowed.

It could be that one of the mixer valves are faulty, can you isolate them to determine which one?

Arnak