HETAS log burner smoking in bedroom

[ecswtrav]

Not sure if this the correct section but wondered if there were any HETAS experts who could possibly advise?
We had an inset stove fitted in the front room in a Victorian era house by HETAS registered installers. Works great with no problems at all.
I had the same chaps out to install a log burner in the back room - this time not an inset but a small 5kw traditional log burner. The same 904 grade flue was used. The guys fitted the burner and a few days later over the weekend I decided to run it. Within 15mins I noticed a smell in the bedroom above and in a dark room with a torch on I could see swirls of smoke coming out of the fireplace.
Rang the chaps and they came out in no time, removed the flue and checked it and then reinstalled the stove pipe etc. We tested the fire and the same again in the room above.
Being genuine guys, they returned the following day with a new connector and new stove pipe. Removed and reinstalled again....with once more the same results. smoke swirling in the bedroom above.
The front room fire has the same setup in terms of their being a bedroom above with an open fireplace but there has never been an instance of smell or smoke.
We contacted the flue manufacturers who said a small amount of oil is used in the construction of the flue but I've been running the stove to see if this clears up (with a carbon monoxide alarm in the bedroom above) but there's no sign of it stopping.
The only difference between the front and back room is the front room has an anti downdraught hanging cowl and the back room has a traditional hanging cowl with birdguard.
The HETAS guys are stumped and I think the smoke isn't exiting the chimney fully and somehow backing up as the flue will be hung too low below the pot - the HETAS guys tell me this isn't the case.
Has anyone experienced such a thing? Thanks a lot

 

[andytw]

How about sticking some smoke pellets in the wood burner and then putting a USB camera up the bedroom fireplace ? You should be able to get a long USB cable. At least you could conduct your own safe investigation at minimum cost. Using the pellets would absolutely rule out the flue oil question.

 

[Brigade77]

Wasn't this covered on Jeremy Whine Fri 03/02/17 or is my De-Ja-Vu faulty?

 

[shambolic]

Bridges broken in chimney causing lounge flue to mix with bedroom flue.
You need a liner fitted

 

[Doggit]

You've used a liner in the second installation, yet there's smoke coming from the chimney in the bedroom, so either there's a downdraught bringing the smoke back down the chimney into the bedroom, or there's a crack in the liner, allowing the smoke across a crack in the chimney breast. Can they get on to the roof easily, block up the bedroom chimney, and then see if the problem still exists.

Can you post a picture of the chimney pots.

 

[cross thread]

suspect its down draught on the bedroom flue pulling smoke from stove as it terminates flue on chimmney,fit taller pot or cap bedroom flue

 

[ecswtrav]

Thanks for the replies. The USB camera sounds like a good idea but I can lie on my back and look up the chimney with a torch - the smoke isn't noticeable really in the chimney only the swirls in front of the torch...and smell. I think too that the downdraught is bringing smoke into the bedroom but I don't understand why the smoke is not exiting the pot as the metal liner goes through the pot on a hanging cowl...from what I can see of diagrams. Looking at the chimney there's only one pot on top and its been flaunched over so I wonder if its possible for the smoke to leave the metal flue liner in the hanging cowl at the terminal and deflect and seep down the sides of the liner somehow and back into the chimney...then down into my bedroom? The liner company have been superb and sent me a new liner when I explained the problems. It doesn't help that a new baby is going into that room in a few months so the last thing we need is any risks like this.
The Hetas guys have said they would come back but I worry they'll spend a day grafting, install a new liner and we will have the same thing all over again if something isn't done at the chimney end. Maybe fitting the new liner may resolve the issue?

 

[Doggit]

Are you saying that both the living room and the bedroom chimney exit into just one chimney pot. If that's the case, then that would be where the problems coming from, they're joined somewhere up in the loft. It would mean that they've got to seal the top of the chimney pot, so that nothing could go back down. It also suggests that you've got no insulation round the liner.

 

[ecswtrav]

It seems doggit that the chimney flue with the metal flue liner in is separate to the bedroom chimney flue where the smoke is coming out. I shine a torch up and there's no sign of the flue liner as its a separate brick flue from down below. The bedroom brick flue turns at the top so I cant see where it meets the chimney pot or figure how it's been capped off. What puzzles me is that surely there shouldn't be any smoke anyway if there's a metal flue liner that terminates properly? That was my argument with the Hetas chaps. The fire in my front room has the same setup but no smoke backing up into the bedroom above - only difference is it terminates on an anti downdraught cowl in the shape of a UFO. I'm just assuming the flue liner has dropped and there's a brick or two missing between allowing smoke to backup down the wrong brick flue and into my bedroom. But you are right, the flue liner isn't insulated which would make it easy for smoke to backup.
I lit the fire again this evening and removed the inspection hatch - no smoke down below for certain so its connected up well that's for sure. Just something going in up above or a crack in the flue liner.
Would it be worth experimenting with a new antidowndraught cowl first before trying the new flue liner?

 

[lostinthelight]

If the chimney was not properly cleaned before the new flue pipe was installed could it be getting hot enough to to burn off any soot/tar thats contacting it?
litl

 

[Agile]

In the room with the fire, is there a vent to the outside for combustion air?

Tony

 

[bernardgreen]

it be getting hot enough to to burn off any soot/tar thats contacting it?
litl

In which case there is a serious hazard of a chimney fire.

Many chimneys that are not in use have convection driven down draughts of cold (heavier ) air into the warmer ( lighter ) air in the room.

As has been said the smoke from the fire may be leaving the chimney pot and then some of it is then being sucked down the other chimney and into the bedroom

 

[Doggit]

Would it be worth experimenting with a new antidowndraught cowl first before trying the new flue liner

Definitely, as there should have been one in the first place, so it begs the question as to why they did them differently. I'm not sure how long they've been doing this, as the connector and the stove pipe they changed wouldn't have made any difference whatsoever.

Oil in the flue liner would give a different smell to smoke, so I think you can rule that out, and I wouldn't have expected much smoke to come back down the adjoining chimney if it was the wind blowing it down, but it is possible - you'd need to block the bedroom chimney at the top to determine that. The flue liner could have dropped (negligence in fitting the cowl), and hopefully they'll be honest when they get up there - ask for a photo maybe - but as you've got the new liner, I'd almost be inclined to suggest they redo the job properly, just in case there is a brick loose between the chimneys.

 

[oilboffin]

Needs a heavyweight liner and needs to be properly backfilled.Bob

 

[ecswtrav]

The fire itself is less than 5kw tony so a vent isnt needed from what I've read although there is one in the room anyway just in case. The liner is a 904 multifuel high spec job not a cheapo one so I'm hoping the problem is at the terminal and checking the connection and fitting a new cowl will help. I'm sure as you say dogget there's a problem at the connector and whoever has flaunched the chimney over has probably knocked a brick out leaving a joint for smoke to get through to the adjoining stack. Why it's backing up out of the cowl is a puzzle as it's a proper multifuel cowl but just not an anti downdraught one. I may ask the guys to remove the concrete on the chimney and see whether it has been properly separated. Apparently they've been at it for years and in fairness they've returned to me several times so I'm hoping they come back to fit the new flue. I'll get the replacement flue fitted, a new anti donwdraught cowl and see if they can break the concrete off the top of the chimney for a check. And take some photos! Any better suggestions please let me know as I'll give the guys a shout this week . Thanks a lot.