Tracer Gas - Drain or not?

[venton]

I've got a guy coming round who is going to try to trace a leak in my heating system using tracer gas (sealed system).
He said I don't need to drain the system, but if I want to I can drain half out. He's worried he might not have enough gas.
I have no experience of this, but I would have thought all liquid should be drained and the system pumped with gas only.
Can anyone who know about these things tell me what the truth is. Thanks.

 

[Whyme]

Tracer Gas Leak Detection & Fixing - Trace and Access

 

[Whyme]

thats how they do it

 

[CHRISX]

I've got a guy coming round who is going to try to trace a leak in my heating system using tracer gas (sealed system).
He said I don't need to drain the system, but if I want to I can drain half out. He's worried he might not have enough gas.
I have no experience of this, but I would have thought all liquid should be drained and the system pumped with gas only.
Can anyone who know about these things tell me what the truth is. Thanks.

Hello venton,

Identifying leaks using Tracer Gas is usually an expensive proposition - usually on Commercial / Industrial systems where either the cost is not prohibitive in terms of the `value` of the system / Contract - or where it is covered / agreed by the Insurers.


I think that Systems would normally be specified to be fully drained - but from what you have been told probably the Tracer Gas would still find any Leak by escaping even if the system is only partially drained.


I take it as `obvious` that there are reasons why the Leak cannot be found by the `normal processes` - for example Pipework is running under floors / expensive flooring that cannot be accessed to check joints and where any Leak would be soaking into the ground under the Building - or similar circumstances - ?


I hope that You won`t mind me asking:

Is this Leak detection being carried out on your Home`s Heating system ?

Have they given You any idea of the Cost ?

Will the cost be covered in full by your Home Insurance ? [If it is at your Home]


Also - would You mind posting a follow up after the Tracer Gas Leak detection has been carried out as I / other Members might be interested in the findings - especially why `normal methods` of finding the Leak were not possible.

"Good Luck" - with finding the Leak and being able to rectify it without too much expense to You for accessing it to repair and for reinstating the area.

Chris

 

[Whyme]

sounds like some mush with gas and a sniffer doing it on the side tbh. bit ottt for a house.

 

[venton]

Ok an update..
The reason this is being done is to prove there isn't a leak really, as I suspect the boiler.
For two months the combi boiler has been showing a drop each day of between half and one bar. And hence water is being added to the system.
It isn't coming out the prv, baloon over that, it isn't coming out condensate pipe.
No visible signs of leak.
Plumber pressure tested section where pipe is under screed, held 3 bar for 24 hours.
Pressure tested rest of system and saw drop...but after he left I found a tiny leak on rad joint, perhaps this was it.
Pressure kept dropping when boiler running.
Didn't want the house torn apart, as my suspicion is the boiler. It's only 3 months old.
Leak guy came round with thermal camera. All quite normal and we could see all pipe work with it.
Emptied system and pumped tracer gas in. No trace of leak. We opened every radiator bleed after checking to see gas was there and detector working which it was. Checked all pipe runs.
Finally pumped whole system to 2 bar with traver gas and left it to see if there was a drop.
After 2 hours no drop. Of course its freezing outside so had to get the system up and running again.
As far as logic goes, we have no leak. No point in tearing the place apart. ..the pipes run over head under plasterboard ceilings, we'd see a patch after two months of adding water.
The installer however didn't think it's the boiler.
I am now convinced there is a highly unusual fault with boiler, where we lose heating water in the exhaust when it is firing only.
Bear in mind I am a layman so this has been a nightmare. We are losing water but it is going nowhere. Unless I top up, boiler goes off.
I paid for the tests myself (600 quid so far) as no visible damage so no insurance.
I am now going to insist the boiler is faulty and get the manufacturers to replace parts. Someone here suggested secondary heat exchanger could be to fault.

 

[Alex Knight]

Have seen a pinhole leak on main heat exchanger before that only leaked when boiler was up to temp but never leaked enough to leave a trace as it evaporates

 

[CHRISX]

Ok an update..
The reason this is being done is to prove there isn't a leak really, as I suspect the boiler.
For two months the combi boiler has been showing a drop each day of between half and one bar. And hence water is being added to the system.
It isn't coming out the prv, baloon over that, it isn't coming out condensate pipe.
No visible signs of leak.
Plumber pressure tested section where pipe is under screed, held 3 bar for 24 hours.
Pressure tested rest of system and saw drop...but after he left I found a tiny leak on rad joint, perhaps this was it.
Pressure kept dropping when boiler running.
Didn't want the house torn apart, as my suspicion is the boiler. It's only 3 months old.
Leak guy came round with thermal camera. All quite normal and we could see all pipe work with it.
Emptied system and pumped tracer gas in. No trace of leak. We opened every radiator bleed after checking to see gas was there and detector working which it was. Checked all pipe runs.
Finally pumped whole system to 2 bar with traver gas and left it to see if there was a drop.
After 2 hours no drop. Of course its freezing outside so had to get the system up and running again.
As far as logic goes, we have no leak. No point in tearing the place apart. ..the pipes run over head under plasterboard ceilings, we'd see a patch after two months of adding water.
The installer however didn't think it's the boiler.
I am now convinced there is a highly unusual fault with boiler, where we lose heating water in the exhaust when it is firing only.
Bear in mind I am a layman so this has been a nightmare. We are losing water but it is going nowhere. Unless I top up, boiler goes off.
I paid for the tests myself (600 quid so far) as no visible damage so no insurance.
I am now going to insist the boiler is faulty and get the manufacturers to replace parts. Someone here suggested secondary heat exchanger could be to fault.

Hello again venton,

Thanks very much for your detailed reply to my questions - I really appreciate it.

What an irritating situation to be in !

The `Testing` / Tracer Gas Leak detection process does seem to indicate that the loss of water from your Heating system can only be from the Boiler - something similar to what Member Alex Knight has described.

Depending on what Boiler You have - regarding whether the operation of the Boiler re. the Fan / Air pressure etc. will allow it to be fired up with the Combustion chamber open - a Gas Safe registered Engineer might be able to remove the Boiler casing / open up the Combustion Chamber and possibly fire up the Boiler and try to see if there is any `weeping` around the Heat Exchanger which is usually being evaporated when the Boiler is operating.

If You already have a Gas Safe registered Engineer who has done work / investigation for You He will be able to tell you whether what I suggested can be done on your Boiler and it should not take very long if it is possible.

Once again - "Good Luck" in resolving this fairly unusual problem.

Chris

 

[venton]

Thank Chris. It is actually an oil combi. Firebird Enviromax.
The installer will now have a word with Firebird and hopefully they will agree to send an engineer out.

 

[SimonG]

All sounds ott. Installer should have had the manufacturer in before the gas test.

As said could be a small leak on main heat exchanger or secondary into condensate.

 

[CHRISX]

Thank Chris. It is actually an oil combi. Firebird Enviromax.
The installer will now have a word with Firebird and hopefully they will agree to send an engineer out.

Hello again venton,

Thanks for your reply.

You have definitely gone beyond what almost any other Home owner would have arranged in trying to identify the Leak / loss of water from your Heating system.

I am sure that You / the Boiler Installer will communicate details of all of the `Tests` to the Boiler manufacturer.

Having been informed of the testing processes I feel that if it is still within the Warranty they should definitely send an Engineer to investigate the Heat Exchanger etc. for `weeping` when expansion occurs during the operation of the Burners.

Chris