Gas smell from boiler when it switches off.

[Steelmasons]

As one who's a stickler for correct terminology Steely, are you referring to the Gas cock?? Just to clarify, same Hymn Sheet & all that dear boy.

Well Dickie , had I been referring to the ECV then I would have said so , I clearly stated "appliance isolation valve"....this would be the gas shut off valve that was supplied by the boiler manufacturer that resides underneath the boiler Dickie..

 

[Steelmasons]

who's to say there's not a fu.ked relay or transistor on the PCB??

If that were the case the control board would throw an error code.

 

[Restoration man]

Ianmcd and Steelmasons you boys are funny. I'm not going to bite. My story hasn't changed!

Service engineer has taken the sump off and refitted it with a new seal. The seal is a double lip seal and one lip was damaged. Me thinks he knew this happened during service!

Will have to wait and see.

The thing that I'm thinking though is if gas was passing this seal enough to stink why was the inside of the boiler never covered in condensation or pools of liquid in the bottom tray!

 

[Steelmasons]

Stop "thinking" and move on.....
"service engineer" appears to be working late!!......BS..

 

[bernardgreen]

but who's to say there's not a fu.ked relay or transistor on the PCB

If that were the case the control board would throw an error code.

Does this boiler's gas valve have feed back to the PCB to inform the PCB as to whether the valve is open or closed.

Could the apparent leak of gas be related to one of joints in the gas pipework being affected by heat ( thermal expansion ) at the gland (?) plate ( where the pipe work is attatched to the the boiler casing

 

[Restoration man]

Bernard green

The flow and return pipes are fixed into the heat exchanger and go through the casing where they are sealed with a rubber gromit. There is no bulkhead connection fitting across the boiler casing.

Cheers

 

[Agile]

Service engineer left about 30 mins ago. He has taken the sump off and refitted it with a new seal. The seal is a double lip seal and one lip was damaged. Me thinks he knew this happened during fitting!

Well, obviously the sump should have a proper effective seal.

But that is still within the room sealed boiler case!

Nor would it explain why you say that you are smelling "gas" in your room.

I use exclamation marks because as far as I can see, no instrument has ever been there to measure this "gas" that you can smell.

I usually ask this early on, do you have a particularly sensitive nose?

Have any independent engineers also smelt this gas?

Tony

 

[Restoration man]

Tony you make the point I've been making to the service engineer. I've been convinced it's an internal boiler issue but if thst was the case we would also need a casing leak for it to smell in the room.

The smell only happened after the sump was changed about 4 weeks ago and it was a very obvious used gas smell.

The sump seal was changed. The new one that had been put on was damaged.

So I do think that is our main problem fixed. We haven't had this issue in 5 years of the boiler been installed only since the recent service. It's too much of a coincidence with the damaged seal also.

But the turret seal or the cover seal must also be defective. My background is pressure testing oil industry equipment and the design of clipping the boiler casing cover on top and bottom just doesn't seem very great to me. If the casing seal is so significant from a safety point of view I think it should have more fixing points round the whole perimeter of the casing to ensure the seal is contacted all the way round.

Problem now how do we check the casing seal. All checks to date have been ok. The internal fume pressure has maybe been high due to the sump seal but only an issue when the boiler goes off and the fan isn't able to clear that much fumes from the casing because it's not designed to.

The smell was only ever there after the boiler had gone off.

Cheers

 

[Agile]

I think you need to review how the internal fan operates.

It takes air from INSIDE the casing and pressurised the combustion chamber and forces it out of the inner tube of the flow.

So any leaks from the pressurised sump will only leak into the sealed casing and be resucked into the fan from there.

So still no explanation of how or why "gas" could get OUTSIDE the casing into the room.

You have now called the smell "used gas" whatever that is meant to mean.

Perhaps you should buy a gas sniffer?

There were some cheap ones at about £32 but unlikely to be sensitive enough to respond to a general smell of gas in the room.

You did not answer my question about if you had a sensitive nose and how much others can smell this "used gas".

Tony

 

[Restoration man]

Concur with how the gas is removed by the fan. The air you speak of inside the casing has obviously been drawn in from the outer flu tube. So it is external air which becomes casing air.

Let's agree gas was leaking due to defective sump seal. It leaks into the casing. When boiler is running normally there is a large negative pressure lots going on the spent gas is removed. We have never had the smell while the boiler is running.

When the boiler goes off the fan runs for 4 minutes. This is obviously not enough time to remove the excess fumes from the leaky sump. The fumes then slowly leak into the room past what we've agreed earlier must be a not very well fitting casing cover.

My term used gas is because it's not new natural gas we had been smelling it was a slightly acrid burnt gas smell. It is obviously the fumes from the leaking sump which are flu gases that had not yet gone out the flu.

This is not an overly sensitive nose issue this has been a very obvious smell of used gas or flu gas that myself the wife and engineers had all agreed was very obvious.

I'd never used the term flu gas or exhaust gas because I didn't know for a fact it was that and if I used those terms on here all your thoughts would have been biased towards flu gas problems only. It could for example have been plastic melting somewhere.

Thanks

 

[Steelmasons]

4 minutes is AMPLE time , do you realise just how many air changes this relates too..
This thread is getting foolish now.

 

[Restoration man]

Yes Steelmasons it's a bit long.

Concerns me why the gas smell was coming into the room if your saying 4 mins is great.

Leak in a boiler with defective case seal should never be an issue then if that's the case because the fan should always be removing gases during operation and the 4 minute post purge.

Why even need a casing seal then.

 

[Steelmasons]

Why even need a casing seal then.

Due to the fact that the boiler manufacturer has classified the flueing arrangement as a C13..should you wish to remove the front cover then I suggest you carry out any remedial works required in order to classify the appliance as being a B23....

 

[Restoration man]

Due to the fact that the boiler manufacturer has classified the flueing arrangement as a C13..should you wish to remove the front cover then I suggest you carry out any remedial works required in order to classify the appliance as being a B23....

Your knowledge astounds me you've probably forgotten more than I know. Or your just very condescending and come on a site like this to make you feel really good about yourself. Lol. I think your great. Every forum needs a Steelmasons. Come to think about it most have one!

Ps I honestly dont understand what B23 means but I've just left the cover off anyway so I can see where the CO is coming from.

 

[ianmcd]

The smell only happened after the sump was changed about 4 weeks ago and it was a very obvious used gas smell.


Read more: //www.diynot.com/diy/threads/g...n-it-switches-off.474462/page-7#ixzz4VNWZMtCy

Please explain what a used gas smell is ? you have went from one load of crap to another in your post, you were adamant that it was gas but called out SGN because CO detectors were activating and now it is a used gas smell whatever that is