Heating system leak?

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It appears I have a leak on my heating system somewhere. Had the plumber out three times now - Combi Boiler checks out. Have isolated the hot water system and no leak was found on the boiler. Pressure gauge looks fine. Upon opening the valves to the heating system over approx 2-3 days pressure is lost (F22 error).

Have found a few minor leaks on radiators. All fixed. No further water found and pressure still dropping. There is no leak noticeable on the ceilings or around radiators which led the plumber to conclude it is likely within the floorboards... Now this is where it gets frustrating. I have a 1970s house where the copper piping has been laid over with cement / screed (?) and under tiles! With insulation and carpet then placed ontop excluding the kitchen and utility room.

My plumber said that finding the leak will be a needle in a haystack scenario and once one pops up more can easily follow. We could attempt to find the leak and repair it but he suggested just re-doing the entire system. Initially I looked at the fix route but it appears doing that really is only temporary.

Wondered if anyone else has suffered similar or knows of people that have?
 
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Yeah, happened to my inlaws when they moved. Someone had laid all the pipes into the concrete floor. They went away on holiday and turned off the water at the meter, and I happened to be up there to warm the house up for them as they were coming back. I noticed that not only did the water meter start whizzing around when I turned it on, but some of the upstairs radiators were half empty and cold. On further inspection, you could see where the previous owner had tried to hide it here and there, and you could see water damage on the bottom of some of the kitchen cabinets where they touched the floor.

The solution was the same as suggested by your plumber, ie re-run the pipes. The simplest way is to simply cut the old pipes at ground level, and then run new ones around walls, through ceilings, etc, boxing in if necessary. It's much simpler doing that then digging up concrete floors to lay everything in proper conduits. It really needs doing though, as constant water dribbling into the floor can cause issues like damp and subsidence. It may not look like much, but it adds up when it's leaking constantly.
 
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My plumber said that finding the leak will be a needle in a haystack scenario and once one pops up more can easily follow. We could attempt to find the leak and repair it but he suggested just re-doing the entire system. Initially I looked at the fix route but it appears doing that really is only temporary.

Wondered if anyone else has suffered similar or knows of people that have?
Not impossible to find the leak, just time-consuming. How much of your pipework is in the ground?
 
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I've got a 70's house with heating pipework under screed and have had fears of leaks.

However I have now relocated some of this pipework as we are renovating the house and it was in excellent condition in most places as it was well protected and had room for expansion, plus the old copper pipe is thicker than what we have now. So I think at this age of house it mostly comes down to issues where protection from corrosion was poor of there wasn't enough room to allow for pipe expansion which can cause stress fractures and wear if touching screed/concrete etc.

Hence I wouldn't assume all the pipe is bad, and I would consider locating and repairing just the current leak(s) unless its not too hard/disruptive to change it all. This will give an insight into how the pipes were laid and protected for future issues. You can use moisture detectors or even specialist companies to pinpoint leaks. Also, if you have more than one separate underfloor section (I have three separate drops from the floor above) you could temporarily cap off each one in sequence to isolate the faulty section.

I have now located all my under screed pipework and based on what I now know if I get any leaks I will definitely just replace in place as required and with copper again rather than push fit.
 
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@Steampunk Yep. Got him coming to measure and discuss the various methods on Friday. Not sure if we'll be looking to uplift the existing or simply cut and cap it and lay down new. I want to do it properly.

Not impossible to find the leak, just time-consuming. How much of your pipework is in the ground?
Pretty much all of the downstairs - Looking at a big space due to the garage and further extension - 3 rooms are tiled (Kitchen, Utility and a bathroom). May be by taking up all the carpet we get lucky and can see it but I'm really not holding my breath. Although I have no idea what to look for beyond water damage.

@Simon42 It's more my concern that if one pipe gets a leak when will the next? Depending on the method there will be considerably disruption so part of me thinks it'll just be easier in the long run to re-do the entire system and have him generate a full map of the piping for my records. More piece of mind I guess?
 
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With the pressure drop you are experiencing, I would be surprised if there was not something noticeable when you lift the carpets.

Can your plumber measure the pressure at each radiator, to see if they can narrow down the run that is affected?
 
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With the pressure drop you are experiencing, I would be surprised if there was not something noticeable when you lift the carpets.

Can your plumber measure the pressure at each radiator, to see if they can narrow down the run that is affected?

Pressure at each radiator. It will be the same pressure throughout the loop no matter where you measure it. Unless you mean turn each rad off and check the radiator for loss of pressure.
 
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TBH I don't know what I was thinking. What I had in my head and what came out through my fingers was not necessarily connected.
 
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TBH I don't know what I was thinking. What I had in my head and what came out through my fingers was not necessarily connected.

Dependant on the flow, return and layout of the pipework you could drain the system, and pressure test between radiator feeds (cap one end etc). in theory, this could be very simple if you're half handy and have a pressure tester...

https://www.amazon.co.uk/318927-Ins...id=1542044873&sr=8-4&keywords=pressure+tester

This does depend on the layout of the flow and return and how the radiators tee into this

Edited to add, I have repaired a heating system with a leak through concrete previously with success and no further leaks. I have also chopped the flow and return to a system and ran this around rooms etc. If this was my home I would attempt a repair and prepare to dig the floor and renew completely. Plastic would actually be better than copper in this situation as it has far more flex and insulating properties vs copper.

Running a heating system fully surface mounted looks crap, you might feel differently.

Do you have an external expansion vessel on your system?
 
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@Pabl0 I have a valliant EcoTec 837 Pro which has an internal one I believe. This really isn't my field. If by chance lifting up the carpets we find the leak I would look to repair it. However in the same motion I am prepared to go for a full re-installation. I would not look to a surface job. Looking online a new installation is between 3.5-5k with a new boiler? So hopefully it's not outside of that ballpark.

The guy has checked the internals a few times now. We isolated the Boiler on two occasions with no real leak. I left it isolated other a weekend (Friday to Sunday). Original reading was 2.8 and I came back to it being 2.2 bar. However there was no leak on the boiler or in the PRV area.

The second time I left it isolated for 12hours 8am to 8pm and it went from 2.7 to 2.8bar. Whenever the heating system (radiators) was on the pressure would drop within 2-3 days. Pretty consistently sadly. I did find a minor wet patch on a two radiator caps which I fixed - Made no difference.

The plumber hasn't recommended using anything like leak sealers or using a leak detection service. The cynic in me thinks that's due to him wanting a big job but the other part of me realises that it's more likely they simply don't work or are temporary at best. :confused:
 
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My folks had this exact issue in a 70s wimpy house, it was obvious where the problem was when the carpets were up and a relatively simple fix as well.
 
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My folks had this exact issue in a 70s wimpy house, it was obvious where the problem was when the carpets were up and a relatively simple fix as well.
Was it obvious? I suppose it's no hardship ripping all the carpet up considering I'm going to be looking at having to take it all up anyway. I shall have a look tomorrow eve.
 
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Was it obvious? I suppose it's no hardship ripping all the carpet up considering I'm going to be looking at having to take it all up anyway. I shall have a look tomorrow eve.

It was because of how it had been laid originally and a damp patch was visible and was appearing from behind a skirting board on a wall adjacent to the leak.

I wonder if a pipe / cable finder would help you plot the layout of the pipes.
 
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I did have a leak in a bathroom on the water system (non-heating) which damaged a wall slightly. It would be... Odd if the leak was also there. But I shall have to move the pc and have a look.

Have a similar issue, no visible leak, its in the downstairs walls/floor somewhere, not sure what to do either. No real option other than. Start ripping stuff up. :(
I'm hoping by fluke it is under the carpet somewhere so I can avoid a new system.
 
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I did have a leak in a bathroom on the water system (non-heating) which damaged a wall slightly. It would be... Odd if the leak was also there. But I shall have to move the pc and have a look.


I'm hoping by fluke it is under the carpet somewhere so I can avoid a new system.

Good luck finding it! We dont have carpets downstairs, wood over concrete. :( Going to "excavate" behind/below the boiler check the concealed pipes there first. Almost wish it was upstairs and a visible leak!

Have already had a new expansion vessel as it was relatively cheap to try out first see if it was that. Also tried 2 bottles of the sealant stuff which didnt work.
 
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I've decided to wait until the plumber comes and quotes what he would recommend to do prior to uplifting my entire house. None of the carpet is even remotely damp so the chance of seeing it on the concrete seems... Extremely small.
 
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I've decided to wait until the plumber comes and quotes what he would recommend to do prior to uplifting my entire house. None of the carpet is even remotely damp so the chance of seeing it on the concrete seems... Extremely small.

Unless you can test the pressure on each run of pipe, you're not going to pinpoint one bit to dig up and repair. You're going to have to dig the lot up, or do as my in-laws did and just write off all the pipe laid into the concrete as a bad investment and redo the pipes elsewhere.
 
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Unless you can test the pressure on each run of pipe, you're not going to pinpoint one bit to dig up and repair. You're going to have to dig the lot up, or do as my in-laws did and just write off all the pipe laid into the concrete as a bad investment and redo the pipes elsewhere.
Ah. Okay. I suppose I'll discuss with the plumber the various options on cost. There's a few other piping issues that I need to deal with such as the gas to the boiler being too small... As the floor will be up I am going to do everything...

Just going to throw money at the problem until it is in top nick and just live here until I have a family that's outgrown it (little chance of that). :p
 
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