Leak in hot water tank

[Johnny]

I live in a modern house (around 4 years old), it has a large and small water tank in the attic, a hot water tank in an airing cupboard, and a boiler (central heating) in my garage on the wall.

Tonight the hot water tank in the airing cupboard has decided to spring a leak. Can't actually see or feel where the leak is coming from, but the floor is wet - as is a few patches on the ceiling under the airing cupboard!

What I've done is I've turned off all water entering the house via the stopcock under the kitchen sink. I did this as I was unable to find a stopcock in the attic on the water tank for the feed to the hot water tank. Turned on all hot & cold taps to drain the water (the large water tank in the attic is now empty, the smaller one (for central heating?) is still full). Finally I drained the hot water tank via the draincock in the airing cupboard.

Also, the central heating and hot water systems are turned off.

What I'm unsure of is:

Can I run the central heating with the water turned off ?

Is it safe to leave everything off for the next few days ? my concern here being the pilot light in the central heating boiler - even though the central heating is switched off. Being without water for a few days isn't an issue as I'm a scruff and would rather wait til after the Easter weekend as it'll save an absolute fortune :) Is it safe though?

Obviously I have no drinking/washing water as if I turn the water on via the stopcock then the hot water tank will fill up (and leak!) - isn't there supposed to be a stopcock in the attic for precisely this reason? I couldn't find it. The only other stopcock I could find is in the airing cupboard and is labelled "hot water isolating valve" - could this be the stopcock for the cold water feed to the hotwater tank? it's on a pipe coming from the attic to the bottom of the hotwater tank so it seems likely, but as it's labelled 'hot water' I'd like this confirmed (also, this stopcock is mentioned seperately from the one that should exist in the attic in the booklet I got when I bought the house)...

Thanks in advance, John (who doesn't want to call out a plumber on Good Friday $$$$)

[Dave Baker]

I'm getting well confused with all these tanks - the one in the airing cupboard is called a cylinder - but let's work through it anyway. The hot water cylinder is filled from the large tank in the loft which will also supply the cold water to the bath. If there is no stop valve between the two then you have to isolate the mains supply to the large tank but all you need to do to achieve this is tie up the ballcock with a stick and a piece of string. No need to shut the water off at the mains or switch off the central heating. All you'll lose is all hot water and the cold water to the bathroom. Cold water to the kitchen sink will be straight from the mains and maybe the loo is also direct.

The cylinder fills from the bottom NOT the top so check again to see if there's a stop valve between there and the large tank in the loft.

Dave Baker - Puma Race Engines

I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.

[Dave Baker]

Oops - I originally gave up before reading your last paragraph properly (well at all actually) having become exasperated by the excessive number of "tanks" in the post. Only spotted it when checking if my reply had sent ok. Seems like you have already found your hot water cylinder stop valve without knowing it so no need to tie up the ballcock now. Just close the valve and put the mains supply back on.

Dave Baker - Puma Race Engines

I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.

[Lurch]

On Fri, 9 Apr 2004 01:46:33 +0100, in uk.d-i-y "Johnny" strung together this:

Yes, if you follow the rest of the replies below.

You can switch it on.

If you turn the valve off in the airing cupboard labelled 'hot water isolating valve' you can then switch the main cold water stop tap back on and you'll have heating and cold water running. That tap in the airing cupboard will just isolate the hot water.

Consider it confirmed.

Should and do are two entirely different words to housebuilders!

[PoP]

A doomsday scenario might be if he got a slow 2nd leak in the CH circuit, perhaps in a pipe joint under the ground floor, where water in the circuit dumped. If the CH system is not replenished then the possibility exists that the boiler might fire up on empty.

I presume this could cause damage to the boiler?

Bear in mind however that sometimes these gate valves are a bit leaky. So you turn the valve off and water still dribbles thru.

I would turn the valve off and leave the HW tap in the kitchen fully open for the duration. That way should there be any leakage in that valve any water which gets thru ought to dump into the kitchen sink.

Unless the plumbing is such that the HW tank feeds taps from the top end, in which case oh-oh.

PoP

[Johnny]

Thanks for the replies everyone.

I've decided to leave the mains water turned off, as I can't be 100% certain that it's the hot water cylinder that's leaking - it could be one of the 4 pipes that run from the attic down through the floor and may be leaking under the airing cupboard floor (I have a total of 7 pipes coming from the attic into the airing cupboard)

Also, the other reason why I was concerned about whether it's safe to leave the pilot light on the central heating boiler is because (after looking at drawings in DIY books etc) there seems to be pipes that enter the hot water cyclinder - even though I can have hot water without the CH being on and vice versa.

[Lurch]

On Fri, 09 Apr 2004 05:22:07 +0100, in uk.d-i-y PoP strung together this:

Yes, which is why I said at the top of the reply switch the heating on

*if you follow the rest of the reply*, i.e. turn the water back on so the CH tank has a water supply.

Won't work like that,

Because of that. To be certain it is off you could either turn the valve off then disconnect the pipe below the valve and fit a stop end. Or you could remove the valve while the tank upstairs is empty and fit a quarter turn ball valve.

[Matt Beard]

Not really - if the house is only 4 years old the system will be indirect so isolating the hot water cylinder will not prevent the heating circuit from getting topped up correctly. Also the OP said he had two tanks in the loft - one would be for the CH system.

Um, I have yet to find a (working) system that feeds the hot taps from anywhere other than the top of the cylinder. You need to drain the cylinger from the drain c*ck which should be roughly where the cold water feed from the isolating valve enters the cylinder. You will need some hose and some way to get the water away. It may be worth getting a friend or family member with some plumbing knowledge to help out - or if you have to get a plumber in! You can't empty the cylinger from the hot taps.

[John Stumbles]

You can tie up the ball-float valve on the big tank in the attic which'll stop the HW system getting any water, then you can turn back on the mains stopcock to get cold drinking (and cold washing and flushing the bog) water. You can run your CH system too, but set the programmer for HW OFF otherwise it'll try in vain to heat up the non-existent water in the cylinder until the cylinder thermostat says it's hot enough. Won't do any harm but a waste of energy.

[Johnny]

Yeah, but I'm not completely sure that it is the hot water cylinder that's leaking and not one of the pipes that go into the floor in the airing cupboard (from the attic) - all I can tell is that the raised floor in the airing cupboard was wet, so I won't be able to tell for sure if it's the cylinder or one of the other pipes untill the cylinder is removed - and I'm not going to tackle that one myself (too scared/inexperienced).