How do I find leak in pipework without taking up floor?

[johndmf]

Last year I put in a new combination boiler - a worcester greenstar 25si. The system keeps on loosing pressure. My plumber has come round and we have checked all the radiators and valves for leaks and tightened all the nuts by the radiators. He suggested I get Worcester Bosch out to check the boiler as it is still under guarantee. The engineer came out and checked the boiler and he also checked all the radiators and valves and could find nothing wrong. He showed me how to isolate the central heating system, which I did. The pressure didn't drop and when I turned the screws back on the pressure did drop, so the leak must be in the central heating pipework.

It is a rented flat, so I have to keep on going round to repressure the system. I have asked the tenants to look for any leaks or wet patches, but they can't find any and I have also been into the flat downstairs to look for damp patches in the ceiling.

Now the heating system is turned off, the pressure is not dropping so much, maybe 1/2 bar every 2 or 3 weeks - but at one stage it dropped 1 bar in 24 hours.

My plumber has now said we need to take up the flooring to look for the leak, but I want to avoid this if at all possible, as all the rooms have hardboard nailed to the floorboards with either laminate or carpet on top so it could cause a lot of damage if it turns out to be the last bit of pipework we check!

I have also chatted to another plumber who has suggested fitting a filling loop with a pressure reducing valve set to 1 bar and then we just wait for the leak to show itself with a damp patch somewhere. I am a bit wary of doing this as my tenants don't really look for damp patches and I am concerned that if I keep on filling the system like this it may cause damage the boiler or heating system.

From searching on this website, I have seen I can get a specialist plumber who can find the leak with either thermal imaging or by putting gas in the system and I will get a quote for this.

I have seen another suggestion saying to pressure up the system to 2 1/2 bar (while cold) and then check the radiators and valves again to see if I can find any leaks. Is this safe to do (i.e. will it cause damage to the pressure relief valve?)? Also, could I pressure up the system to say 2 bar and turn on the heating as it seems to loose pressure quicker with the heating on, or would that cause more damage.

Does anyone else have any suggestions?

Any advice is very gratefully received!

Thanks,

John

 

[holty]

could iso the boiler. then fill the system with a compressor thats with the pipework dry though.you then may be able to here a hissing noise.

 

[Deleted member 105431]

try fernox F4 leak sealer. put a balloon over the prv discharge to make sure it is not dripping intermittently.

 

[johndmf]

The specialist plumbers I phoned said they would drain down the system, fill it with gas and listen for leaks with specialist equipment, but their office is closed today (it was an engineer who answered) and I have to phone back on Monday for a quote. What would a reasonable price for this be?

I looked into using the fernox leak sealer, but the boiler has 2 years of a 3 year guarantee to run and the technical department at Worcester Bosch advised me not to use it as it could cause damage to aluminium heat exhanger and also generally as it is a condensing boiler and it heats up the water very quickly.

What about the filling loop and pressure reducing valve suggestion or pressuring up the system suggestion. Are they safe?

Thanks,

John

 

[holty]

The specialist plumbers I phoned said they would drain down the system, fill it with gas and listen for leaks with specialist equipment

bit like using a compressor and your ear

 

[johndmf]

bit like using a compressor and your ear

I'm not sure I feel confident enough to do that myself, as I would have to drain down the system and then somehow get the compressor to pump air into the system and at the same time go round trying to listen for leaks. Presumably the compressor would be quite noisy, so that might make it difficult to hear any hissing sounds?

I would like to try pressuring up the system and then checking round the radiators and valves again and also checking the ceilings below for damp patches. I have been told the system should normally be pressured to between 1 and 1 1/2 bar. I have also been told the pressure release valve will operate at around 3 bar but that if you leave the system at 3 bar it can cause stress and possibly make new leaks in the boiler which would defeat the object.

What can I safely pressure the system up to:-

1. when cold

2. when the heating is on

Can I safely leave it at this higher pressure for a few hours?

Presumably I don't need to isolate the heating system when I do this (I'm assuming I can't do this if the heating is on). To lower the pressure I assume I just bleed a radiator.

Thanks,

John

 

[ffsday]

Hello Johndmf,

I have the same problem as you with my boiler.

Have you solved your problem? Did you find your leak? Is your boiler now behaving?


Regards: ffsday

 

[johndmf]

Yes, we found the leak.

When I phoned around, one of the plumbing firms mentioned it might be covered by my buildings insurance under a trace and access clause. I phoned up the insurance brokers and they confirmed it was. The insurers sent out someone with heat detecting equipment. They couldn't find the leak with that, but they were able to see the location of all the heating pipes without taking up the flooring.

They then sent someone with gas detection equipment. They drained down the system, filled it with gas and then went round with some highly sensitive equipment trying to find where the gas was escaping from. It took them a couple of hours to find as the leak was so small. They then sent out a plumber who only had to take up the floor where they had found the leak. They got it spot on, which was a big relief as I was originally worried they would end up having to take up loads of flooring before finding the leak.

It turned out that the plumber who originally laid the system about 10 years before had laid copper pipes across a supporting steel beam. Over the years when people had been walking across the floor, it had squashed the pipe slightly and caused a very small leak. The water was dripping on to the steel and mostly evaporating before it hit the plasterboard of the ceiling of the room below, which is why there was never a sign of any leakage on the ceiling below.

He cut out the damaged pipes, replaced them with plastic pipe and then put pieces of plyboard either side of the pipes on the steel so that when we put the flooring down it didn't squash the pipes anymore. That has solved the problem, but if it happens again, at least I know the likely cause.

When I had been phoning around the specialist plumbers I was being quoted around £500 to £700 to have the leak detected by gas. I just had to pay an excess of £100. Even if it hadn't been covered by insurance it would have been worth locating the leak this way as it would have cost a lot more in damage to take up all the floor boards.

Good luck.

 

[ffsday]

Yes, we found the leak.

When I phoned around, one of the plumbing firms mentioned it might be covered by my buildings insurance under a trace and access clause. I phoned up the insurance brokers and they confirmed it was. The insurers sent out someone with heat detecting equipment. They couldn't find the leak with that, but they were able to see the location of all the heating pipes without taking up the flooring

Good luck.

Thanks very much for your advice, johndmf.

I've checked the insurance policy and found the 'trace and access' clause, thank heavens! Did your insurance company react to your phone call alone? Or did you have to produce a claims form? Or could the claims form only be produced when the investigation and access work was completed and you had received the invoice? Who actually selected, mobilised and paid' the investigating company?

Once again thanks a million!

regards: ffsday

 

[johndmf]

Thanks very much for your advice, johndmf.

I've checked the insurance policy and found the 'trace and access' clause, thank heavens! Did your insurance company react to your phone call alone? Or did you have to produce a claims form? Or could the claims form only be produced when the investigation and access work was completed and you had received the invoice? Who actually selected, mobilised and paid' the investigating company?

Once again thanks a million!

regards: ffsday

I can't remember exactly what happened as it was a while ago. I did it all by phone with a claims advisor appointed by the insurance company. I didn't have to fill in a claims form as I was able to explain in detail what the problem was and what tests/checks we had already done to eliminate other possible causes. As a plumber had already checked the boiler and I'd also checked all the radiators for leaks, they accepted it was a problem in the central heating system. They were going to send out a surveyor, but as there was no physical evidence of the leak (just the pressure dropping on the boiler) they didn't bother. The insurance company appointed and paid for the investigating company and the plumber who did the repairs, so I didn't pay any of them but did pay my excess to the insurance company.

I was told I was only covered for finding the leak and accessing the leak and I would have to pay for the plumbing repairs. However as the repairs were straight forward and the plumber did them once he had found the leak, they didn't charge me. I did run the risk that had there not been a leak in the system and the cause had been something else, then I would have been charged the full cost of the investigating company. This wasn't an issue for me though as I'd already decided to get in an investigating company anyway.

Different insurance companies may have different procedures, so the best thing to do is to phone up your insurance company and explain the situation, but before doing this you should be reasonably sure the pressure drop is caused by a leak in the system and not something else.

 

[heydiy]

Hi John

I have a same problem. Could you tell me what company helping you detect the water leak? Do they offer repair leak service as well?

the plumber you menthioned is from the same company? the system problem really annoy me. if u could give me the detail about the company. I will really appericate it.

Thank you!

 

[johndmf]

Hi,

You'll need to find a company local to you. The company the insurance company employed were called Munters. They didn't repair the pipework and a plumber from a different company came to fix it. To find a company near you do an internet search for 'leak detection services'.

 

[HERTS P&D]

Can't you find anyone in China???

Andy

 

[dhutch]

try fernox F4 leak sealer. put a balloon over the prv discharge to make sure it is not dripping intermittently.

Seen this in rent accom asa s student, followed by another house 'fixed' with fernox. But it appears you have found a nice solution to finding the issue and fixed it. Sorted.

Like the idea of using heat detection cameras to find the pipes.


Daniel

 

[heydiy]

Thanks for your reply.John,
May I know which company the plumber from? I m now living in great london. the plumber finally opened the floor and fix it? Do u need any builder to open it and recover the floor? Do I need to prepare pipework map for plumber?

Thank you!

Hi,

You'll need to find a company local to you. The company the insurance company employed were called Munters. They didn't repair the pipework and a plumber from a different company came to fix it. To find a company near you do an internet search for 'leak detection services'.