Questions for any Plumbers on here

Thread starter #1
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I have three water tanks in the loft, two very large and one quite small. The largest, which seems to be the one that fills the tank in the airing cupboard, and the little one both have overflow pipes that run out over my conservatory. This is not an issue until one starts leaking water, which is soon obvious due to the racket it makes emptying onto the conservatory roof. This week, one of the pipes has leaked water out a couple of times for no apparent reason. It's difficult to say as the pipes seem to twist in the loft and disappear under the lagging before they get to the exterior, but the one leaking looks to be from the smallest tank. Last weekend, it started leaking whilst we were out, as soon as I noticed, I went straight up into the loft and looked into each tank, expecting to see one of the tanks full to brimming with a possibly faulty stopcock. I was very surprised to see that none of them were more than half full, no water anywhere near the overflow pipes. The little tank wasn't even half full. There was condensation inside the lids which I suppose could run into the overflow pipe - I couldn't confirm this is the case though as the lids won't remove completely due to some intricate looping copper pipes coming out of the tanks and feeing back in through the lids.

My question is, why is the overflow leaking when the water levels ar so low? I just want to make sure I'm not going to wind up with water coming through the roof.
 

Robin Hood

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I'm no plumber either.
Is one of your small tanks the expansion tank from your boiler.
Is the boiler working ok ?
I'd pull back the lagging to find the exact point of problem and phone a plumber
 

williamalex1

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I think the small tank will probably be the central heating header top up and expansion tank, if you have a systems boiler [ not combi ].
Large tanks ,1 suppling hot water cylinder plus expansion, the other a cold water supply to bathrooms. Experts will be along shortly
 
Thread starter #5
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Not a plumber but could the overflow be from another source like the cistern in the bathroom ?
Unlikely, I can see the two overfow pipes leaving the two tanks and entwining as the go into the lagging towards the roof exit. The bathrooom cistern overflows are located elsewhere.
 
Thread starter #6
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I'm no plumber either.
Is one of your small tanks the expansion tank from your boiler.
Is the boiler working ok ?
I'd pull back the lagging to find the exact point of problem and phone a plumber
Heating is working fine, unfortunately, the loft space is so low, it's pretty impossible to get over to the point where the two pipes disappear into the lagging, I have tried. They do protrude from the roof shortly after the lagging. They definitely come from the two tanks in question, neither tank has a leaking ballcock, neither tank hass water anywhere near the overflow outlet, can't see any sign of leaking water around the tanks, just don't understand why the overflow is expelling water.
 

williamalex1

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Heating is working fine, unfortunately, the loft space is so low, it's pretty impossible to get over to the point where the two pipes disappear into the lagging, I have tried. They do protrude from the roof shortly after the lagging. They definitely come from the two tanks in question, neither tank has a leaking ballcock, neither tank hass water anywhere near the overflow outlet, can't see any sign of leaking water around the tanks, just don't understand why the overflow is expelling water.
Could be steam coming from the expansions pipes into the tanks condensing, maybe water temp too high
 

jim8flog

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As some else has said one of the small tanks will be a header tank for an open venting central heating system if the pressure in the heating system gets too much there is a pipe which feeds the water in to this tank if this overfills then the excess goes out of the overflow pipe.
 

Robin Hood

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As some else has said one of the small tanks will be a header tank for an open venting central heating system if the pressure in the heating system gets too much there is a pipe which feeds the water in to this tank if this overfills then the excess goes out of the overflow pipe.
This happened to me with my old boiler, the overflow kept running due to steam condensing in the overflow tank. The boiler was fixed (faulty thermostat) problem solved.
Sounds like you need to get a very thin plumber who can crawl into the roof space !!
 
Thread starter #10
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As some else has said one of the small tanks will be a header tank for an open venting central heating system if the pressure in the heating system gets too much there is a pipe which feeds the water in to this tank if this overfills then the excess goes out of the overflow pipe.
In this case though, I would expect to see the water level close to the overflow outlet at the time the pipe is leaking, and this is not the case, which is why it is baffling me.
 

Stuart_C

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I have three water tanks in the loft, two very large and one quite small. The largest, which seems to be the one that fills the tank in the airing cupboard, and the little one both have overflow pipes that run out over my conservatory. This is not an issue until one starts leaking water, which is soon obvious due to the racket it makes emptying onto the conservatory roof. This week, one of the pipes has leaked water out a couple of times for no apparent reason. It's difficult to say as the pipes seem to twist in the loft and disappear under the lagging before they get to the exterior, but the one leaking looks to be from the smallest tank. Last weekend, it started leaking whilst we were out, as soon as I noticed, I went straight up into the loft and looked into each tank, expecting to see one of the tanks full to brimming with a possibly faulty stopcock. I was very surprised to see that none of them were more than half full, no water anywhere near the overflow pipes. The little tank wasn't even half full. There was condensation inside the lids which I suppose could run into the overflow pipe - I couldn't confirm this is the case though as the lids won't remove completely due to some intricate looping copper pipes coming out of the tanks and feeing back in through the lids.

My question is, why is the overflow leaking when the water levels ar so low? I just want to make sure I'm not going to wind up with water coming through the roof.
Have you had any issues with your heating?

I would say the heating is expanding back into the F&E tank if the the ballcock is not passing.

Send me your email address and I'll forward the invoice ๐Ÿ˜

If you need anymore advice fire me a pm and I'll help as much as I can without seeing it.๐Ÿ‘
 

Stuart_C

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OP said the tanks were only half full and not near the overflow ?
My thought is if theres a circulation issue and its venting back in the F&E and overflowing, that water that has expanded out of the system would be replaced by the water thats already stored in the F&E. The ballcock is doing its job hence the tank is only half full.

I might be wrong like , I've only been doing it 20 odd years.
 
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