Tank Overflowing - Please help!

[Sal831]

Also, Seco services, I felt the pipes to the hot tap on both the units I could get to, and I found that the kitchen sink tap did do as you said, it went cold very quickly after turning the hot tap off, however as described when I isolated the mains supply to the tap, the cws tank continued to fill. Very strange! I can't think of an explantaion.

Sal

 

[Dan Robinson]

Not that I am in any state to read the whole thread, but it seems that it is either the shower or the cylinder coil.




From reading your first and last posts (and skim reading the rest) I might suggest both.

 

[TonyW2]

Its good to find that isolators were fitted.
So far so good.
Is the level of water in the cold water tank (usually the big one), when full at a higher level than the water level in the c/h feed tank and is it definately the higher cold supply tank that is overflowing? (As in that case it is not the hot water storage cylinder coil that is leaking.)

 

[TonyW2]

Also, Seco services, I felt the pipes to the hot tap on both the units I could get to, and I found that the kitchen sink tap did do as you said, it went cold very quickly after turning the hot tap off, however as described when I isolated the mains supply to the tap, the cws tank continued to fill. Very strange! I can't think of an explantaion.

Sal

Possibly the pipe is the furthest from the hot water tank and cold weather in kitchen! But if the overflow is continueing when tap isolated, it can't be that.

 

[TonyW2]

Incidently, I don't think its relevant to the problem but just in case, it seems the ball cock in the c/h header tank is leaking just a small drip at a time and when we had a plumber come round he isolated the header tank by turning off the stop cock. He never turned it back on, and I hadn't realised, and so the system has been functioning for the last week like that. (It has been overflowing for the last 3 weeks).

If that ball cock is leaking, and you said earlier that the tank does not have any overflow pipe, its a good job the valve to it was turned off!
If you have turned it back on, why is not flooding? Fit an overflow--nice DIY job now that you are getting interested.
This is the tank you say is getting some hot water into it. If not substantial, this is probably just gravity from the c/h circuit, unless there is evidence of water being pumped in via the expansion pipe when the pump is running. Check it.

 

[Sal831]

Ok, will check water level heights this evening, the header tank for the c/h is not situated on the floor, it is on a shelf, so I think they are about the same height, but I will double check as I can't remember for sure. It is definitely the cws tank thats overflowing, as I have said, the header tank for the c/h doesn't have an overflow.

Will definitely fit an overflow to the c/h header tank. I have left it isolated for now.

Will report back.

Thanks again for your help.

Sal

 

[TonyW2]

It's the top surface of the water heights levels that you need to check, of course, but in your case, as the central heating feed tank is isolated, there can be no supply via the c/h system and so the hot water storage tank coil must be OK.Therefore you have narrowed it down to the last mixer--ie the shower.

Just check that isolating that one does stop the backfeed.

If it does, try to adjust the mains cold feed pressure to it with the isolating valve so that it is the same as the hot water flow from the hot tank,( but you may need a better solution than this simple one.)

 

[Sal831]

Great thanks for your help.

I will test the final mixer tomorrow and hopefully it will confirm it!! I have a feeling the plumbers fitted a pressure reducing valve when they fitted the shower, maybe this has gone. Once I have 100% confirmed the problem I'll start working on the solution!

Thanks again for all your help.

Sal

 

[Sal831]

Hi Guys,

Thanks for your help, it was indeed the shower. Did the final test today, and as soon as I had isolated the shower the tank stopped overflowing....eureka! Only problem now is that I don't know whether the shower mixer was faulty, or if it should never have been used on our system.

Does anyone know whether it is ok to use a mixer on a shower, when we have mains fed cold water and gravity fed hot water from the tank?

The plumber had fitted a pressure reducing valve on the mains feed.

Thanks again for all your help.

Sally

 

[seco services]

you can use a mixer valve as yours has been done but its not the best idea and you can't always get the cold pressure down low enough with a pressure reducing valve.
would of been better with an equalising valve.

http://www.rwc.co.uk/public/gplumb/pequal.pdf