Thermal Imaging Heat Detection?

Soldato
Joined
17 Aug 2009
Posts
18,466
Location
Finchley, London
Hi guys. got a problem with a water pressure leak whenever my central heating is on. Central heating was laid and installed in 2012. To fill you in, a year ago I had a slow pressure leak and had to repressurise the boiler every few weeks until eventually it was once a week. I had a gas engineer a year ago put sealer into the system and that held the pressure fine for a year.

Now the bar pressure goes down from whatever I set it at, usually 1.5 bars, to 0.3 after just a couple of hours of heating along with an F22 message flashing on the screen saying 'safety switch off, no water pressure'.

I had a different gas engineer come over a couple of weeks ago to service the boiler (Vaillant Ecotec Plus 831) and he inflated the diaphragm in the expansion tank as he said it was flat. He reckoned that should fix it. Well it made no difference. He came back a few days later, re-checked the boiler, said it's absolutely fine and put some sealer into the system. While he was here he went into my front room to check the radiator and we had a catastrophe, the valve broke away from the radiator followed by flooding from the radiator and water peeing out of a crack in the upright copper connecting pipe that the valve sits on. Fortunately I have laminated floor and not carpet. He stopped the flooding though.

Then I had a plumber come over couple of days ago to replace the radiator as he was unable to get the broken bits out of the old rad. The heating is all working but the pressure is still going right down to F22 after less than 3 hours heating. I wanted to try a process of elimination. I turned off all but one radiator today and just ran that rad. Pressure still went down and the F22 returned, so I repressurised again.

I could continue with the process of trying each radiator, but I think this leak is affecting all of them. I called the plumber and he suggested I get a company in with a thermal imaging heat detector to pinpoint where under my floor the leak is. And then he said he could come back and fix it. But of course it looks like flooring will have to come up.

It's a ground floor flat with concrete floor under porcelain tiles in the kitchen and adjoining bathroom, and then floorboards under laminate flooring in the hall, bedroom and front room.

I've already spent £460 with the gas engineer and plumber and haven't really gained anything. I need to get this sorted but wondered if you think I should get a thermal imaging company in?

I called my buildings insurance broker last week and was told that I'd be covered for repairs and making good on floor replacement, but I have to pay the first £400 excess. What do you recommend I do? The whole thing is really ******* me off now because it's expensive and I'm dreading pulling flooring up. :(

It's easy enough for me to repressurise the boiler, takes a second, but every time I do that, I'm washing away the rust inhibitor.
 
Sounds like a lot of water loss, no signs of damp anywhere?
You might also have luck listening for the leak, buy a cheap stephoscope and go round at night listen near the radiators first. You may even be able to do it with just your ear pressed to the ground.
Try turning radiators off one at a time to stop the flow along the run to that rad, should make it even easier to hear leaks along that pipework.

I don't envy you though, took me ages to find a leak I had which lost about 0.5 bar over a month. Turned out it was on the back of a vertical aluminium rad, the drip was drying by the time it ran down so left no wet patches on the floor.
 
Have known people to cut their losses on underfloor if it goes wrong. Does insurance not have leak detection cover?
 
UV dye is another leak detection option ? not sure if £60 is cheap or expensive https://uvgear.co.uk/uv-leak-detection-kit-central-heating

While he was here he went into my front room to check the radiator and we had a catastrophe, the valve broke away from the radiator followed by flooding from the radiator and water peeing out of a crack in the upright copper connecting pipe that the valve sits on.
I didn't really understand what he had done to provoke that ... but never mind ... he over torqued something ? - but he has professional insurance ?
 
Have known people to cut their losses on underfloor if it goes wrong. Does insurance not have leak detection cover?

Not sure what you mean by cut their losses? Not sure about my buildings insurance leak detection cover. I'll call the guy and ask him. He just told me last week that I'd be covered for any work but I'd have to pay the first £400, which is a bummer, but I don't mind that if the rest of the job ends up going into multiple hundreds.


UV dye is another leak detection option ? not sure if £60 is cheap or expensive https://uvgear.co.uk/uv-leak-detection-kit-central-heating


I didn't really understand what he had done to provoke that ... but never mind ... he over torqued something ? - but he has professional insurance ?

He went to check the radiator, I didn't see what he did and he told me the bit I've arrowed in yellow just broke away. And the vertical copper pipe coming up from the floor had some cracks in it. So no idea, but it was obviously weak and had he not done that, who knows if it would have just come away at some point and I'd have been struggling to stop water coming out. I'm not going to bother with buying detection equipment myself, this is too major for me, I need professionals in. I'm wondering if it's worth calling british gas to investigate or call the original gas engineer that installed my central heating? Seems like thermal imaging detection is the way to do it. Apparently it's about £400 to buy one, so maybe there's a thermal leak detection company that I could get in to investigate it.

The new radiator:

Radiator.jpg
 
Not sure what you mean by cut their losses? Not sure about my buildings insurance leak detection cover. I'll call the guy and ask him. He just told me last week that I'd be covered for any work but I'd have to pay the first £400, which is a bummer, but I don't mind that if the rest of the job ends up going into multiple hundreds.




He went to check the radiator, I didn't see what he did and he told me the bit I've arrowed in yellow just broke away. And the vertical copper pipe coming up from the floor had some cracks in it. So no idea, but it was obviously weak and had he not done that, who knows if it would have just come away at some point and I'd have been struggling to stop water coming out. I'm not going to bother with buying detection equipment myself, this is too major for me, I need professionals in. I'm wondering if it's worth calling british gas to investigate or call the original gas engineer that installed my central heating? Seems like thermal imaging detection is the way to do it. Apparently it's about £400 to buy one, so maybe there's a thermal leak detection company that I could get in to investigate it.

The new radiator:

Radiator.jpg
Check your home insurance. Mine has cover to find leaks up to £5000.

The cut losses point was about a colleague of mine saying his underfloor heating went kaput, and the cost of tearing up and fixing was untenable so he just had a cold bathroom.
 
Check your home insurance. Mine has cover to find leaks up to £5000.

The cut losses point was about a colleague of mine saying his underfloor heating went kaput, and the cost of tearing up and fixing was untenable so he just had a cold bathroom.

Oh I see. Well, I don't have underfloor heating but yeah, it's still a case of finding a leak presumably under the floor, since the boiler and radiators seems ok.
I have buildings insurance which will cover repairs and make good the lifting of flooring. Is home insurance something else? Like, I don't have contents insurance (I know, I should), just the buildings insurance.
 
Oh I see. Well, I don't have underfloor heating but yeah, it's still a case of finding a leak presumably under the floor, since the boiler and radiators seems ok.
I have buildings insurance which will cover repairs and make good the lifting of flooring. Is home insurance something else? Like, I don't have contents insurance (I know, I should), just the buildings insurance.
Just checked - it is in my builders cover as "Trace and Access". I have up to £10k cover to find the source of a leak.

On a quick Google it says "slow leaks" can be subjective so I'd be clear to insurer that it is cutting out your heating. Seems slightly more urgent than a typical "slow leak".
 
Sounds like a lot of water loss, no signs of damp anywhere?
You might also have luck listening for the leak, buy a cheap stephoscope and go round at night listen near the radiators first. You may even be able to do it with just your ear pressed to the ground.
Try turning radiators off one at a time to stop the flow along the run to that rad, should make it even easier to hear leaks along that pipework.

I don't envy you though, took me ages to find a leak I had which lost about 0.5 bar over a month. Turned out it was on the back of a vertical aluminium rad, the drip was drying by the time it ran down so left no wet patches on the floor.

Well it's an old house, like edwardian and has always been prone to some damp, but I've done a lot over the years to keep it mostly at bay.
I won't bother with a stethoscope but for the time being will continue with radiators one at a time.


Just checked - it is in my builders cover as "Trace and Access". I have up to £10k cover to find the source of a leak.

On a quick Google it says "slow leaks" can be subjective so I'd be clear to insurer that it is cutting out your heating. Seems slightly more urgent than a typical "slow leak".

Interesting, i'll see what the insurer says. Yep, definitely more than a slow leak now.
 
Sounds like you might had a dodgy pressure relief valve ( have you been refilling it a lot and perhaps over filled it a few times? it could be the value is stuck open?) because most of the time a leak will be at a joint or a connection to a rad so you should be able to see it, any damp spots or flaking wallpaper or paint anywhere? As its a Vaillant boiler I would recommend getting one of their engineers out to have a look at it, that is if you are confident you dont have a leak anywhere. We had a local gas engineer condemn our boiler as unsafe who then wanted a £90 call out fee off me, I argued with him and said he has not doing anything to it and said he wouldn't because its unsafe. I agreed to pay him if another engineer said the same thing, I called Vaillant they sent one of their engineers out and he fixed it (was a faulty float switch) and I think the cost was about £140 for the call out and the parts required to fix it. Needless to say I called the other guy back and told him that my boiler was back up and running and that I would not be paying the £90 call out fee.
 
There's an old plumbers trick where you add some perfume/cologne in to your central heating system then sniff out the leak. Not tried it myself and could be an issue clearing it out after.

 
Ive seen a trick by old plumbers where they add a really strong smell like a bottle of aftershave into the system and then over the next few days ask the homeowner to “keep a nose out”

any leaks can usually be smelt and at least pin pointed to a room.

Edit :- beaten too it! As above really.
 
And it's definitely not coming out of the pressure relief valve/overflow? I had similar albeit it not as quick a drop (week not hours) on same boiler as yours where the valve had failed, replacement of that fixed the issue there and then.
 
Thanks for the suggestions guys. Well regarding pressure relief valve, I'll check it tomorrow. But I seem to recall the first gas engineer checking that a year ago when the problem appeared and I think he said it was ok. And the gas engineer who came recently didn't mention it at all, so I'm assuming he would have done if he suspected it. I really wish it was that, it would be so much easier!
 
Thanks for the suggestions guys. Well regarding pressure relief valve, I'll check it tomorrow. But I seem to recall the first gas engineer checking that a year ago when the problem appeared and I think he said it was ok. And the gas engineer who came recently didn't mention it at all, so I'm assuming he would have done if he suspected it. I really wish it was that, it would be so much easier!

Presume you're not getting much water coming out the pressure relief overflow. You'd obviously see this amount of water.
 
Any of the engineers considered the pressure gauge is faulty?

I was going to suggest this when I posted initially because the gauge on mine does not work but even if the gauge doesn't work that wouldn't result in a drop in pressure. My boiler works fine but the gauge reads 0 bar.
 
Well guys, I decided to call the gas engineer that installed my central heating system in 2013. He's just been over to look around, discuss and recall to memory as best he could where the pipes were laid, and is going to call me with a date next week to investigate the problem and fix it.

We checked the pressure relief valve and there's no issue with it. He suspects the issue lies under the floor in my front room. He's going to have to break some laminate boards and lift floorboards and at first suggested a more discreet part of my hall where broken laminate wouldn't be as visible where he could crawl underneath. But then he decided he could probably get a good view under my front room by lifting floorboards in the shared hallway which faces the front room, and that shared hall doesn't have laminate flooring so is a bit easier to deal with. He might still have to lift laminate flooring or even tiles in the kitchen but he's got detection tools, a thermal detection device and cameras where he said he should be able elimimate areas of my flat and find out where the leak or leaks are. Hopefully it'll be one place but we don't know yet if there are multiple holes or not.
Gonna be expensive whatever happens and probably a couple of visits by him.

edit:
Well it looks like Howdens still sell the same laminate flooring I've had for 8 years so at least it can replaced. https://www.howdens.com/joinery/flo...-grey-oak-laminate-flooring-222m-pack-sdh3578

Looks the same as mine anyway. This is a spare board I have. And if the porcelain tiles have to come up, I hope B&Q still sell the same.

20210319-135816.jpg
 
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I've not read the entire thread, but I saw recently there are companies that put gas through the central heating pipework and then use a gas leak detector to find where the problem is. This may help narrow down the location.
 
I've not read the entire thread, but I saw recently there are companies that put gas through the central heating pipework and then use a gas leak detector to find where the problem is. This may help narrow down the location.

It's not a gas leak, it's a water pressure leak.
 
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