Gas smell from boiler when it switches off.

[Restoration man]

Desperate to get a fix to a smelly boiler. My gas service company are stumped with my Logic 30 boiler.

When the boiler goes off the washroom it is in stinks of a gas smell. It's not necessarily pure natural gas it has a slightly dirty smell to it.

Gas feed to boiler and CO checks have been done on 4 separate days and they never find anything.

Burner gasket was replaced. Gas valve taken off and seals checked. Everything checked has been ok.

Operation of boiler is normal flu gases etc checked.

Fan operation is good and when the fan runs after the boiler has stopped the internal boiler shows air quality as fresh as outside external air.

It appears something is happening intermittently.

They've mentioned changing the main circuit board as this may not be controlling the fan properly all the time.

But this is total speculation there are no fault codes ever showing and nothing scientific to suggest the board has ever been faulty.

The change of the burner gasket made no difference so I feel they are now just going down the road of replace and hope.

Is there any more obvious possibilities for a smell when the boiler stops?

When the smell is present the CO detectors aren't going off. Got one on the ceiling 1.5m from boiler then one just through a door in next room as a back up. Then every room in house has a smoke-CO detector.

Thanks

 

[Dan Robinson]

Think I'd be looking at the condensate drain and trap arrangements.

 

[Jackrae]

Or perchance the boiler casing seal. Is the post-burn purge working correctly ?

 

[Restoration man]

They took off the casing seal and cleaned it! I presume gave it a wipe and put it back. It was fine to be reused.

Post burn purge has been considered. When tested casing air was as clean as external fresh air. Is it possible or probable the post burn purge isn't always working?

The fan has always run what I'd call full power on the purge every time I've been there to witness it.

Dan can you expand on your comments about condensate set up please.

Thanks

 

[Jackrae]

They took off the casing seal and cleaned it!
Thanks

Wonder why they took off the seal and cleaned it as it would normally be expected to remain stuck in position and not require "cleaning"

 

[footprints]

Think I'd be looking at the condensate drain and trap arrangements.

Sounds like a good idea, might well be the smell is coming up from a drain trap or overflow somehow.

 

[J_N30]

All I'd ever say is if you have a smell of gas call national grid to checks there's no leaks. It's free. 0800111999

 

[Restoration man]

National grid or our equivalent SGN were the first here about 9 days ago and signed it all off safe. My service company has been here 4 times since with 3 different people.

There is a technical fault probably intermittent I'm trying to get some options on from experienced trades on here so I can suggest there checked next time the service company come back which is Monday.

 

[Dan Robinson]

Above comment doesn't help

That is a rather arrogant reply. You're not the only one reading these threads.

It is very sound advice.

 

[Restoration man]

Fair point. I've removed the comment. Apologies Joe N30.

It is frustrating though when comments are made which aren't based on the OP description which states Ive had gas engineers out 4 times and everything that's been tried to date.

Understandable if me and a mate from the pub where trying to fix a gas boiler ourselves!

£300 bill so far and same problem!

 

[Agile]

The condensate drainage route is a very important line of enquiry.

It could be that somehow drain smells are being sucked into the room and these, while unpleasant to smell, will not be measurable on any boiler testing equipment.

So where is the condensate draining to?

Tony

 

[J_N30]

Fair point. I've removed the comment. Apologies Joe N30.

It is frustrating though when comments are made which aren't based on the OP description which states Ive had gas engineers out 4 times and everything that's been tried to date.

Understandable if me and a mate from the pub where trying to fix a gas boiler ourselves!

£300 bill so far and same problem!

To be fair your topic title is Gas smell. Admittedly I didn't read the thread hence starting my reply... all I'd say is...... other people reading this need to know the service is available and free.

 

[Nige F]

Desperate to get a fix to a smelly boiler. My gas service company are stumped with my Logic 30 boiler.

When the boiler goes off the washroom it is in stinks of a gas smell. **It's not necessarily pure natural gas it has a slightly dirty smell to it.**





Is there any more obvious possibilities for a smell when the boiler stops?


Thanks

I've been watching the thread, and not commented because I'm not Gas Safe reg (just a retired old skool plumber) As other members have said there is a strong possibility that you are getting a drain smell because of the way the condensate pipe is installed. The condensate is part of the boiler that comes under Gas Safe jurisdiction, so can be looked at by anyone but a GS person must do any alterations if necessary.

 

[Dan Robinson]

Fair point. I've removed the comment. Apologies Joe N30.

It is frustrating though when comments are made which aren't based on the OP description which states Ive had gas engineers out 4 times and everything that's been tried to date.

Understandable if me and a mate from the pub where trying to fix a gas boiler ourselves!

£300 bill so far and same problem!

Unfortunately not every engineer is equal. But we post advice based on the information given with the stance that many others will find it too using search engines. It's Why We also Come down hard on some of the archair regulars that sneak online when their care in the community nurse isn't looking.

 

[ianmcd]

National grid or our equivalent SGN were the first here about 9 days ago and signed it all off safe. My service company has been here 4 times since with 3 different people.

There is a technical fault probably intermittent I'm trying to get some options on from experienced trades on here so I can suggest there checked next time the service company come back which is Monday.

Are you really saying that SGN turned up to a smell of gas when your boiler switches off and signed it off as all safe as you call it ? never in a month of sundays, they would have told you to get a registered gas engineer out and would have turned it off and fecked off TOFO, they are what is called First call operatives FCO and do not hold any qualifications to certify your boiler as safe