Boiler flue issues - basement and flue termination

[Mjward]

Hello

new to the forum so will say thank you in advance to all and any assistance you can provide.

background: current boiler installed in Basement in 2011. Six months ago it failed gas safety for the first time, I sought a second opinion and same thing. Diagnosis being that the flue termination is too close to the ground.

Nothing has changed re the setup so I’m not going to get bogged down in why it was fine and now it isn’t,the regs are the regs.

after a bit of googling I’m confused about the rules that govern this, in particular definitions of the terminology. I know flue clearance must be 300mm from the ground but clearance of what? My logic would have thought the outlet of the flue ie where the gases escape (which is 2.5m from ground) but can only assume my setup is failing because it covers the height the piping exits the property at the horizontal (at 0.15m above a dug out area that enables circulation for an airbrick into the basement)

if it is in fact 300m from where the pipe simply exits the property (even if not terminated there) what are my options?

1) does increase the depth of the dug out area to increase the distance from it to the horizontal to 300mm suffice (even if still below adjacent “normal” ground level)
2) drill through room above and take flue further vertical so it doesn’t exit the property horizontally until 300mm above normal ground level
3) anything else?

once again appreciate any advice you can give
Thanks

 

[PETE 123]

If the air intake for boiler is below the grd then it would fail as if it snowed may block up air intake or effect boiler operation.

 

[Mjward]

Hi PETE 123

Thanks for your response. It was my understanding that the air intake is only happening at the top of the flue vertical extension kit (in red in the diagram) which is 2.5m above ground. The pipework that is coming out from the boiler in the basement and exiting the property below ground is not open to air intake, it's just a bend upwards to the extension

 

[gmartine]

At least 300mm of clearance above ground level (I). At that height though (< 2m) you'll have to install a terminal guard, no need to raise it to 2.5m.

 

[Mjward]

At least 300mm of clearance above ground level (I). At that height though (< 2m) you'll have to install a terminal guard, no need to raise it to 2.5m.

So can you understand why two gas Safe engineers have failed the setup I have given the outlet for the flue on top of flue extension is 2.5m above ground level. They seem to be solely judging it on height pipework exits the property which is not 300mm above ground but surely the regulations deal with the termination of the flue ie where the gases are escaping and don't care about covered pipework itself?

 

[Last Plumber]

As @PETE 123 points out, if the air intake was in a dug out below ground level, it would fail.
Is the air intake in there?

Have you a photo of the external flue and dug out.

It is possible that there has been a misunderstanding of the regs but we would need to see the actual flue and its surroundings in order to pass comment.

 

[Mjward]

As @PETE 123 points out, if the air intake was in a dug out below ground level, it would fail.
Is the air intake in there?

Have you a photo of the external flue and dug out.

It is possible that there has been a misunderstanding of the regs but we would need to see the actual flue and its surroundings in order to pass comment.

Apologies I'm not currently at the property so don't have access to better pictures but pls find these from my records include a diagram of it helps

[automerge]1583318119[/automerge]
Plus image from valiant themselves of the extension

 

[ShaunCorbs]

I would want the flue to the same height as the plume kit eg replace the flue and bring it full height both the air and exhaust