HETAS log burner smoking in bedroom

[ecswtrav]

Hi All, Just thought I'd give you an update on the log burner situation as you were all good enough to give me some advice. The guys came back today, fortunately I was off work. First thing they did was remove the stove, metal flue and cowl. They then did a smoke test with several smoke bombs up the brick lined flue...I witnessed the outcome...nothing, absolutely nothing in the bedroom above....I was disappointed to see this as it somewhat didn't make sense. Only thing evident was smoke leaving the chimney which I could see from a Velux window clearly.

Next thing, the guys decided to install the new flue liner even though we all inspected the current liner (I wont say 'old' liner as its hardly been used). Anyway, the liner was fine...looked like new actually...but we proceeded with the new liner. Add to that a brand new 5" anti downdraught cowl (like the one I have fitted on the front room with the same setup and no problems or leakages). I'll add an image here of the cowl so you can see how it connects.

Anyway, they connected the fire up and we were all good to go. The lads added the kindling and then a log and I thought I would go upstairs and grab my torch ready to check back in 10mins or so when it's really going. Anyway, turns out the torch was still in the bedroom so I headed in....and the smoke was absolutely billowing out the bedroom fireplace. Arguably the worse I've seen it - there was no need at all for a torch as the room was full of smoke and it was pumping out.

I let the lads know and they looked through the access hatch on the metal plate at their connection just above the stove - nothing. no smoke visible and nothing coming back into the room.

I noticed the following:

The chimney fireplace in the bedroom was 100% heated up. You stick a torch and your head up the chimney and you cannot see the metal flue liner. yet there was no question it was warm in the opening - I'm assuming the flue was very close.

It's hard to tell whether the smoke is coming back down the chimney and into the bedroom or somehow coming from below and from around/the back of the hearth. If it was coming from below though surely the flue connections would be giving smoke off which I don't think they are?

The lads told me they didn't put sealant around the cowl at the top where the metal flue meets it as the jubilee clip gives a really tight grip as it is - again I wondered if there was some seepage with the jubilee not quite doing its job. Having said that, the smoke that filled the room you would say it would have to be a massive gap.

The noticeable smoke only appears when you put a new log on and it's burning at a high rate. Probably a bit obvious that one, but nevertheless. Whilst its burning slowly/under control smoke is still present in front of a torch but not like the billowing witnessed to start.

My Plan:

Inform Hetas that it isn't repaired. Hopefully they will come out and investigate???Although I've no idea if this is what they do and what else they can possibly do that the installers havent?

Remove the cast iron surround in the bedroom and brick it up....not ideal really but with a baby on the way I don't have many options it would seem.

Anyway, I'm stumped now so I'll see what Hetas advise and keep you all posted for anyone who may have a similar experience in the future. Pain in the butt this one!

 

[ecswtrav]

 

[Doggit]

I think the clue may be in the high heat in the bedroom chimney, and it's burning off old soot in there. Has the bedroom chimney been swept.

If this is the case, then you may have to add vermiculite to stop the heat getting across to the bedroom flue.

 

[ecswtrav]

Thanks Doggit - I've stuck my head up that bedroom chimney and it doesn't look like there's in soot in there - just old crumbled mortar it seems and relatively clean bricks. It hasn't been brushed though. Maybe it's worth me having the bedroom chimney swept to be certain. Instead of vermiculate could I use the blanket type insulation do you think. What amazes me is how the stove installers don't have any suggestions!

 

[Doggit]

It'll depend on the how much space you have round the liner. I suspect the blanket would be fine if it's a 5" liner, but not if it's a 6" in a narrow chimney. This'll partially be down to the installers to make a judgement call, but the blanket ensures that no part of the liner is against the wall - well in theory.

 

[Corgigrouch GTi]

I too think that the hot liner is in contact with something combustible in the chimney, possibly a lump of tar, a small blob can make a lot of smoke.. If the feathering between the two chimneys is gone then it could be finding its way in to the bedroom through there.. Were there any marks on the outside of the flue liner that was removed?

 

[bernardgreen]

How soon after the fire is lit does smoke appear in the bedroom ? Is the metal flue liner insulated.

If the liner is not insulated and is therefor heating ajacent brickwork then the smoke in the bedroom may be vapours from heated residue on the brickwork of the bedroom chinely/.

The liner for my log burner had an insulating blanket fitted. It seems this is a standard requirement for all log burners as the flue liner can get hot enough to ignite tar and other deposits that it comes into contact with.

 

[Doggit]

If the tar etc was being burned in the main chimney, then you'd see wisps of smoke coming up the side of the liner, but they may not be easy to spot. They'd need to take the cowel off to see smoke coming up the side, but it would be a way of checking.

 

[ecswtrav]

The guys didn't mention anything about insulation and to be fair, I've only learnt about these things since installation problems. Usually I always research jobs first but with lots on I just trusted installers with some good feedback on the internet. You live and learn I guess! I think the idea of the liner pressing against brickwork and heating up something that hasn't been removed makes a lot of sense - would a blanket surrounding the flue stop this? or would it just slow down the speed at which this tar/soot is heated? It is a 5" flue doggit so it would fit a blanket I'd like to think like the one in bernardgreen image.
It has crossed my mind too that after the initial burst of smoke (happens once a log goes on usually and the fire starts raging) things settle down and I'm not sure whether I'm seeing smoke in front of the torch or some kind of vapour/steam from the heat? Pretty certain its smoke though to start with - you couldn't mistake it earlier. And it does stink. Today's smell though could be the oil in the liner as the flue manufacturers suggested.

Just doesn't make sense that the smoke bomb didn't come out in the bedroom as surely this would have crossed missing midfeathers? Thanks again for the help everyone

 

[bernardgreen]

Just doesn't make sense that the smoke bomb didn't come out in the bedroom as surely this would have crossed missing midfeathers?

The liner may be heating brickwork that separates the two chimneys until the residue ( tar ) on the bedroom side of the brickwork starts to vapourvise. In other words no smoke is going through the brick work, only heat is going through the brickwork and smoke ( tar vapour ) is being generated in the bedroom chimney

 

[lostinthelight]

I think you will find that the principal reason for any form of insulation surrounding a flue liner is to maintain a higher temperature to aid draw, this is of greater importance as woodburner get more efficient
litl

 

[Doggit]

Any oil on the liner will burn off in a couple of days. If it smells, then somethings getting very hot, or more likely burning, but steam wouldn't smell very much, and if it was steam or vapour, then where's it getting refreshed from. We've got to assume that they capped off the flue when they did the smoke test, or it would have just taken the path of least resistance. If they have done the smoke test properly, then the smoke not getting across does tend to suggest it's a heat issue. Does the smoke build up in the bedroom every time you put anther log on the fire, and die down in between.

 

[ecswtrav]

The smoke test was done with chimney open as I could see smoke leaving the pot. The chaps didn't think of capping it and neither did I thinking about every little issue. As you say that would have cleared things up if smoke came.out in bedroom. Today's experience of using the fire meant it smoked ridiculously after the first log...Almost like a chimney in the bedroom...Then died down to only being noticeable with a torch, before adding a log which increased the smog to the extent of you noticing it but no way near like the first startup. I'm going to.light the fire again Tomorrow and have a feel inside of the brickwork to see if it's evident things are heating up greatly. Certainly there is warm air/warmth at the bedroom fireplace along with the smog

 

[Corgigrouch GTi]

How soon after the fire is lit does smoke appear in the bedroom ? Is the metal flue liner insulated.

If the liner is not insulated and is therefor heating ajacent brickwork then the smoke in the bedroom may be vapours from heated residue on the brickwork of the bedroom chinely/.

The liner for my log burner had an insulating blanket fitted. It seems this is a standard requirement for all log burners as the flue liner can get hot enough to ignite tar and other deposits that it comes into contact with.

View attachment 114072

The purpose of the insulation is not to insulate the liner from anything that may burn in the chimney... Remember it is a chimney and should be free from any combustibles.. It is as already been said to ensure that the flue warms and promotes a good flow, also the flue should be hot to help reduce the risk of Creosote and the formation of tar.

 

[bernardgreen]

The purpose of the insulation is not to insulate the liner from anything that may burn in the chimney

That is not what HETAS told me. HETAS said it is to prevent ( reduce the risk of ) the brickwork of the chimney becoming hot enough to ignite flammable material in contact with the brick work.