Wheres the leak???

[Olwol]

I’ve got a leak in my central heating system.
I’m losing about 1 bar a day and this has been happening for the last 5 days. It works out to be about 3 pints a day.. yep approx 15 pints of water loss.
I have just had new carpets put down so yes it couldn’t have happened at a worse time.
I know the issue is with the pipe work rather than the boiler as I have turned the central heating ball valves off at the boil for 24 hours and the boiler didn’t lose any pressure.
When I turned the ball valves back on the pressure dropped.

My question is how do I find the leak without ripping all the carpets back up one by on or having to pay someone to acoustically find the problem.
Another question is has anyone ever used leak sealant and doesn’t effect the boiler? Oh.. And does it work effectively?

 

[regsmyth]

15 pints should be pretty obvious if it's a leak in a floor space or loft. If it's under the ground floor, is there anyway of checking?
Are you sure it's not the boiler pressure relief valve discharging outside?
Maybe the carpet fitters did something like stick a nail through a pipe?
If the carpets were done properly with gripper rods, they shouldn't be too difficult to get up and put back.
Good luck.

 

[Olwol]

I own the flat below but theres no sign of a leak. I'm guessing this is because I have a suspending ceiling with double plaster board as well as being filled with rockwool!

Any suggestions on how to find the leak?

 

[regsmyth]

As far as I know there's no magic way to find your leak.
You could push up the pressure in the system to almost trigger the prv, then you might hear it spraying around under the floor? This might alternatively cause an electrical fault...
You could wait till your ceiling comes down, or accept you've got some work to do - taking up carpets and floorboards to check.
There are experts who can find leaks with thermal imaging cameras, but I reckon by the time you get them in, the leak will be pretty obvious.
Are you sure it's not the prv on the boiler leaking? ie when the boiler is on, the pressure might be getting too high and then it would come out of the pressure relief valve.

 

[Bahco]

Get the carpets and floorboards up. They will have to come up anyway to repair the leak if it is under the boards anyway!

 

[Olwol]

I'm sure the leak isn't the prv because i switched off both central heating ball valves at the bottom of the boiler for 24 hours.
During this time the pressure didn't drop. When I then opened the ball valve the pressure went down. That indicates the problems in the central heating system rather than the boiler, right?

 

[Olwol]

Does anyone know whether those leak sealants are any good?

 

[Bahco]

Does anyone know whether those leak sealants are any good?

Not used them but I would personally get the job done properly. Get them boards up and stop pussyfooting around!

 

[Olwol]

I think if you'd spent over 1000 pounds getting some quality carpet down you'd be thinking twice about pulling it all up again.
Thank you for you coments but I'll hire a thermal imaging device before I randomly pull up floor boards.

 

[mattylad]

I am pretty sure that it does not cost £1000 to lay carpets unless you also factor in the cots of the carpets.


When you do find your leak you are still going to have to lift the carpets to get at it.

Carpet fitting tools can be got from B&Q and its quite easy once you have a go, especially if it has been professionally laid beforehand.

 

[wotsupnow]

just a thought, are any sections of pipe accesible ? you could hire a pipe freezer to isolate a section to help narrow down the leak ?

Pete

 

[diverdee]

when u have to repressurise the boiler where is all the trapped air?.usualy its in the nearest rad to the leak

 

[muggles]

I'm sure the leak isn't the prv because i switched off both central heating ball valves at the bottom of the boiler for 24 hours.
During this time the pressure didn't drop. When I then opened the ball valve the pressure went down. That indicates the problems in the central heating system rather than the boiler, right?

Not necessarily, it could have dumped out the PRV when you reopened the valves

Is there any boxing anywhere on an outside wall where pipes are running? Is there a hole through to outside in it? If so then it's entirely possible that your leak is running into your cavity

 

[Master of None]

Before you do anything check the PRV discharge pipe. You may think this is not where the water is going but it is the easiest thing to check. It is very possible your expansion vessel is flat or leaking. I have copied my reply to a previous post below.

Had this problem, I had to have my expansion vessel changed, its air valve was letting by. It works like this.
1. Set pressure heating cold.
2. Turn on heating, water expands, pressure cant go anywhere except thro the relief valve to outside.
3. Pressure remains at around 2.5-3 bar (relief valve set pressure) while heating is on.
4. Heating turned off. pressure drops to below initial fill pressure because some water has escaped thro relief valve.
5. You top it up and on it goes..... Back to 1.

So if you isolated the boiler while warm, the water in the rads contracts as it cools. you then open the valves to boiler, pressure drops.
I also think if you were loosing this much water a day and you have access to the flat below you would see something.

Please let us no how you get on.