Major water leak in central heating system

[MaryJane7]

I have a 3 bedroom terrace house built in 1988. The central heating rads and pipes were put in when new, except for one additional radiator in extension about 10 years old. New condenser boiler and pump fitted 2 years ago and its a gravity fed system.

Yesterday, with no warning and with the central heating having been working as normal for 2 hours, the central heating system system just emptied itself completely in about 30 minutes. Fortunately the boiler stopped by using its safety valves etc. There is no water showing anywhere and trying to fill up the header tank again fails as the water just runs out continuously.

The piping downstairs is buried in the concrete flooring.

I have called our plumber who is as mystified as I am and is coming tomorrow to look at the piping for the extension as a first move, but this does mean taking up some of the concrete floor.

Anyone had experience of this sort of problem? Where has the water gone? And what's the best way forward? Any advice would be welcome. Thank you.

 

[Burnerman]

Could this be a coincidence, we fear, that the thaw has started somewhat?
If the leak is so severe, it should show itself soon enough.
Sometimes (anorak on) a stethoscope helps to roughly locate the leak as you can hear water passing through various pipes.
John

 

[BingoBongo]

throw in some aftershave so you can smell it too

 

[ScottCheg]

throw in some aftershave so you can smell it too

haha. Aint bread any good?

 

[Burnerman]

Mmmmm nice
With luck, Mr. Plumber will be able to isolate the supply to the extension, so that MJ7 can at least be warm before the floor comes up - if it has to.
John

 

[MaryJane7]

I keep the heating on all day, although off at night. The coldest part of the house is the conservatory but there is a radiator in there and the air temperature has never gone below 7C. Is it likely that the central heating pipes in the concrete floor would still burst?

 

[Burnerman]

Hey, who can tell? You musn't bury copper pipes in concrete though - the cement action eats them clean through. Maybe this is whats happened?
John

 

[electronicsuk]

There is no water showing anywhere and trying to fill up the header tank again fails as the water just runs out continuously.

Surely the header tank would have been trying to fill the system from the moment it started to empty? If that's the case, and the header tank shows no signs of filling despite continuous water flow from the ball valve, it must be one heck of a leak. So much so that I find it hard to believe it could even be a problem in the concrete floor, as the pipes being embedded in there would limit the leak somewhat.

Do you have any suspended floors where the leak could go unnoticed?

Hey, who can tell? You musn't bury copper pipes in concrete though - the cement action eats them clean through. Maybe this is whats happened?
John

Not directly, but nothing wrong with it if they are in conduit or otherwise correctly insulated and sleeved.

 

[AfterburN003]

Before starting to rip up the concrete i think i would capoff the pipework going to the conservatory under the wooden floor to see if that stops the leak....if it does , the leak is under the concrete...if it doesn't , the leak is under the wooden floor. (Pray its the wooden floor! )

 

[Ihavenojob]

depending on boiler,it could be the heat exchanger leaking and going out through the condense pipe.

 

[Burnerman]

If the F/E tank can't make headway, it must be a hell of a leak...if its not visible, you would think you would hear it
John

 

[Nige F]

Are there any drain off pipes Outside through the wall , with drain cocks on ... hidden under the snow ...Frozen, thawed, leaking now

 

[MaryJane7]

Many thanks for suggestions so far. Today we've:

1. dug up concrete to expose pipes linking kitchen with conservatory, no sign of any damp and pipes in good condition

2. pulled up all carpets to check condition of concrete floors, no damp (all our floors are concrete downstairs with no suspended floors or floorboards)

3. looked for any signs outside of drain off pipes, or any water at all. None.

4. Plumber checked heat exchanger and said it was fine.

5. went to loft and turned on the water to the header tank again to see what happened, saw water running out of tank and heard water going round pipes, rads (including conservatory rad) got a little water in them (air came out from bleeder valve) but then later heard water gurgling out of rads again (not all at same time)

5. could hear water gurgling round but couldn't hear anything that might be a leak

6. looked everywhere again to see if there was any sign of water anywhere. None.

7. Turned off water to header tank and gave up.

Where can the water be going? Any ideas on what to try next?

 

[Burnerman]

Turn off every rad, allow the tank to fill...what happens now?
John

 

[Whitespirit66]

This is better than Midsomer Murders. Op, please keep posting!