Strong Gas Smell after new Gas Work on Boiler HELP Please!

9 Nov 2005
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United Kingdom

I am hoping someone might point me in the right sirection.

Sequence of events that may help.

Biasi Boiler Riva M110 32SM/c

1. Bolier operating fine for 4 years
2. Service Call from Biasi Engineer at our request
3. Boiler found to have a below spec gas pressure
4. Advised to Upgrade Gas pipe to boiler
5. After initial visit (before any work done) a 'Chuffing Sound from Bolier when under load"
6. Biass Engineer re-visited and adjusted gas valve and discussed a cut in a pipe in the boiler with head office. This is normal and an approved modification!!
7. Problem of chuffing sorted
8. New gas supply pipe installed and run from meter in 26mm and then to 22mm.
9. Reported smell of gass around boiler and Fitter (not Biasi) came straight round and investigated pipe work. Checked pressure drop at meter and it was 4mb over 2 minutes. He commented that's what it was before any work carried out and said that is acceptable due to gas hob etc.
10. Fittings all seemed ok
11. Fitter then decided to check flue gas, he then decided to set the boiler up as per instructions.
12.. Fitter set the boiler up as per service manual and boiler locked out
13. Biasi (the following morning) confirmed that the 'modifications' will have changed the Flue readings and the settings should be modified.
14. We reported a strong smell of gas in the morning to the fitter and he came back and check everything. he discovered the flue did not have a seal around it and sealed that up.
15. Later that afternoon still smelling of gas when boiler starts up and is in demand.
16. Back he came and checked every fitting in the boiler with 'soapy' water.
This am the boier still has a smell of gas around it when put in demand.

The problem is the fitter has lost his sense of smell.

I have watched him work and he is very thorough and wants to get to the bottom of this.

Any ideas what the issue might be? This all started when we put in the new gas supply which is now 20mb at the Valve.

Thank you in advance

Here is the modification as advised by Biasi Head Office

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I dont normally deal with biasi so cant comment on the "modification" but the pressure drop is within specs ONLY IF THERE IS NO SMELL OF GAS, as you can smell gas the leak will have to be found and repaired, I would turn off the supply and contact biasi (or your other gas fitter)to have this put right.
As Picasso has already stated, if smell of gas present, even 1mbar would not be acceptable. Reading your post, it would seem 4mbar leak has been accepted without confirming the leak is at the hob- instead it would appear, just because a hob exists and there is a 4mbar leak, it must be the hob. Is the gas smell present at the hob or the boiler?

The fact that gas pipe has been modified, it would be prudent to locate the section that fails the gas tightness test, isolate and test to prove the leak does not exist in new pipe run. Also, I take it gas smell was not present before the modification.

The hole in the tube does not appear to be part of manufacturing process. Instead it looks like a rip or a tear.

It may be wise to call these guys to attend the problem PDQ before someone gets hurt. If all fails, call the Gas Safe Register and seek guidance from them

Rest assured, based on what you have written, proper procedures have not been followed. To say the leak was pre-existing is not enough. Last person to tinker with the gas line become responsible to locate and make safe. If he is reluctant to do so, it is then fast becoming a health and safety issue and I can see these guys becoming a token on the Monopoly board with a 'Go Straight to Jail' card.
The obvious way to look for a gas leak is an electronic sniffer which all serous engineers will have. The days of using your nose have gone!

I have never heard of a modification like that and I have set up quite a few M110s including one last week. There was an early mod of cutting a square 10mm hole towards the other end to prevent a tendancy to resonate at low power.

The design of the boiler makes it very unlikely for any smell of gas when its operating.

You have not mentioned the original installer! He fitted it with an undersized gas supply and an unsealed flue. Was he an unregistered builder?

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The smell is near the boiler, which is in an upstairs air cupboard. spoke with Gas Safe this am and we discussed the modifications but they said that it sounded strange. I was asking that if a manufacturer modified a boiler after it has had a UK approval do they not have to record approved modifications as part of a process so other engineers can check boiler make history.

Fitter is calling Biasi this am and will talk to Gas Safe about my call.

Gas Safe technical mentioned that it might be the connection after the valve before it enters ignition chamber and suggested the fitter use a 'sniffer' rather than the fluid which would not show a small high pressure leak.

I guess the only way to check the hob is to cap the supply and retest the drop.

Thanks for the advice.

Safety is my absolute priority ( Ido have a wife and children) no risks being taken.
Hi Agile

The cut you mention is what it was trying to correct. I think we are now at full pressure so the mod maybe surplus.

The Bolier was already fitted when we bought he house. Yes I think it was a dodgy fit as the supply pipe was reduced from 22mm to 15mm to get through walls.

The guy we bought the house off was a developer (large developments) so he must have used some cheap labour to do work on his house!!
The correct mod is not related to an undersized gas supply.

The resonance could occur on any boiler but was primarily on the early ones with a thick rubber hose. Later ones had a thin plastic hose but they had three 6mm holes.

But the location of the 10mm square hole should have been towards the other end.

A smell of gas ONLY when the boiler is running is only going to be caused by a problem AFTER the gas valve and could possibily be an outlet connection but thats pretty unlikely but a sniffer will be the tool to indicate a leak!

Thought an update would be in order.

Long Story and 4 Days Later the issue was resolved.

The leak developed from 4mb to 8mb after the fitter capped his new pipework. SO he started looking at the old pipework, checked Hob Fittings, Old gas pipe. Was at house until 10.00pm. He then suggested staying the night as he couldn't leave the house without capping the meter. He then turned the meter off and slept in our back room!! 1st think in the am he then capped off the old run at an exposed place. I then helped him check his logic. After testing the system again there was still an 8mb leak. I suggested he cap of he new pipework again and test. Still showed 8mb but he re-check his capping and there was some dirt in the cap. Checked again drop was down to 3.5mb.

I had persuaded him to buy a gas sniffer and that arrived later in the afternoon. I had to leave and came back at the end of the day.

He then told me he had found the leak. It was under the boiler floor in the new pipework at the joints. The sniffer picked it up when his 'liquid' didn't he was very surprised at the leaks and couldn't work out how they had occurred.

After all that (4 days ) and suspecting the boiler etc.

All is well now and wife glad he isn't sleeping over now.!!!!!
Alls well that ends well !

Full marks for staying overnight to continue in the morning!

No marks for doing gas work without a sniffer, they cost from £35 upwards.

Was it him who did the leaking pipework?

This is the most bizzare thread I've ever seen! Did he have an overnight bag, just in case?

Did he get the leak down to ZERO?
Thanks Agile and Expertgasman.

No Leak is now at 3mb over 2min Suspect it must be leaking at a joint that cannot be seen in old pipework. Some is under concrete.

If it ever increased we will cap of the old pipework at the meter. It's starts in the old iron pipes and drops into the concrete floor.

And yes he went home to get his sleeping bag!!!!

My wife agreed that was the strangest of situations.

The leaks were of some of his and some of another fitter he brought (who could smell when he purged he system at reconnection.

I help him at the last purge.

Those sniffers are really good.
No Leak is now at 3mb over 2min Suspect it must be leaking at a joint that cannot be seen in old pipework. Some is under concrete.

I'm afraid work still does not comply. The allowance is only applicable if there is NO smell. Once a leak has been established AND a smell of gas, the leak must be FULLY traced and repaired. Not having a pop at you, but I think the RGI (?) leaves a deal to be desired.
He then suggested staying the night as he couldn't leave the house without capping the meter. He then turned the meter off and slept in our back room!!

Why did he not just cap the meter?

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