Cold Water Cistern in Attic is overflowing

P

PJJassal100

Joined
26 Apr 2009
Messages
4
Reaction score
0
Location
London
Country
United Kingdom
Hi
I thought this was an easy one to fix, it had to be a leaking stop cock valve. So I replaced the hole unit and alas the water tank is still overflowing! I spent some time watching the water tank filling up from the valve and confirmed that the it was indeed stopping when reaching the correct level. As I was monitoring it I noticed water level still rising even though the valve had shut off.

A closer look showed, I noticed that water was feeding back in from the exit hole from the tank. Bizzare don't understand how it is possible.

The exist hole feeds the Hot water cylinder which is heated by the boiler, I can only think that the hot water cylinder is over filling and pushing back up into the cold water cylinder?

Any Ideas, anyone?

This is my first post so please let me know if you need information. Please see the diagram below which gives you an idea of my system setup.
Untitled

Untitled


Many thanks in advance
 
Sponsored Links
Sponsored Links
i would go more along the lines of a mixer tap as mogget said
or shower valve passing cold mains to hot gravity.
 
seco services said:
i would go more along the lines of a mixer tap as mogget said
or shower valve passing cold mains to hot gravity.
Click to expand...

Agreed - so for the CWS to be continually filling the mixer tap must be faulty, otherwise it would stop when the tap is turned off.
 
Thanks all for your prompt replies, the change to plumming is a new kitchen fittend a while ago.

We added a dishwasher feed from cold and hot mains, the washming machine was already feed by both cold and hot
and finally a new mixer tap, the previous tap was also a mixer. The pressure in the tap is very high for cold compared to hot water tap.
 
PJJassal100 said:
and finally a new mixer tap, the previous tap was also a mixer. The pressure in the tap is very high for cold compared to hot water tap.
Click to expand...

Like Orwells Pigs, not all taps are equal! There are a lot of cheapies kicking about and this looks like the source of your problem. Think about the logical consequences when both hot and cold taps are open and the cold and hot supply confront each other in the mixer.The flow from the cold mains becomes "connected" to the low pressure hot supply and forces cold water backwards along the system.
 
Then when the hot tap is open and the cold tap is open, the pressure from the cold supply will not be able to feed up past that "one way"valve BUT will hot water be able to come out of the mixer?????????
Unless the pressures are made equal or the tap is a type that does not actually let the cold and hot confront each other, it will never be able to function as a mixer, only as two taps sharing a spout, with priority given to the cold.
(Think of a tee junction and what would happen with unequal pressures on the arms.)
 
Good point ;)

Some time ago I fitted a high pressure mixer to a system with mains pressure cold and low pressure hot. Reason was that customer was having a combi fitted some weeks later so had bought correct tap ahead of time.

As a temporary fix I put isolation ball valves on hot and cold supplies but closed the cold valve a little so less cold would get through. This did work fine. I also fitted check valve on hot. I am aware that the iso valve reduces flow rather than pressure but it did work on this occasion.

(I tried rather than going straight for the more expensive pressure reducing valve).
 
Thanks for the feedback and sorry for the late reply, I will get the valve this weekend and give it a go.

Thanks
 
P.s. for today I have closed the isolator to the hot tap going into the mixer, I hope this will throw some light on the issue if this is the mixer tap causing the problem
 
That may not help, as some designs of isolator will let by when subjected to reverse pressure.
 
D

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
You must log in or register to reply here.
Sponsored Links

Similar threads

S
Cold water tank overflow
Replies
3
Views
916
Rico99
R
M
header tank overflow problem.
Replies
5
Views
2K
madsey
M
F
overflowing hot water cistern
2
Replies
17
Views
2K
Softus
S
H
Continued problem with overflow
Replies
8
Views
4K
harris48
H
W
Overflowing cold water tank
Replies
7
Views
4K
Wotsinaname
W
Back
Top