Woodburner/Flue Question

[Mark A]

Does a stainless steel flue require sweeping? I can't seem to find anything about it online, only information about brick and stone chimneys.

For the past couple of days we've been getting a bit of smoke coming inside when the woodburner door is opened, but only when it has just been lit. Once the fire's going there's no problem.

Thanks,
Mark

 

[Jacob]

Does a stainless steel flue require sweeping? I.....

Quite possibly. It depends on what you burn, how hot, how wet, how well insulated the flue, etc. etc.

 

[Mark A]

We usually burn softwood which we get from a shipping firm we know (the timbers are used to secure goods in containers), though recently we splashed out on a couple of bags of offcuts from a reclaim yard. The wood is mixture of old softwood timbers, pitch pine and a bit of greenheart.

 

[jordec66]

we have had our multi fuel burner for about five years, occasionally when the temp is below zero we experience exactly what you describe. We have our chimney swept but there is always little or no residue in the liner, we were told that the cold affecting the steel liner sometimes causes a backdraught, which is always cured after the fire has been lit for a couple of minutes and the warm liner begins to draw air.

 

[Mark A]

That makes sense, but it's not that cold here! BBC weather says it's 8 Degrees Celsius right now.

 

[Andrewf]

All chimneys need sweeping immaterial of what you burn. In fact insurance companies require proof that you had the chimney swept regularly if you have a wood burning stove. Think it's due to the recent increase in chimney and roof fires caused by the large number of wood stoves.

 

[johnluc]

Mark, the pull on the flue will be a lot less untill it warms up, re sweeping i would say you should sweep it or get it swept at least once a year, here in france we use nothing but hardwood, oak, birch etc and need to sweep at least once a year for insurance purposes, if you are using soft woods ie pine you will get a build up of hard residue from the resins in the wood, a friend had a major problem will downdraught and when he's flue was checked he found the 6" diameter flue was almost completely blocked with a tar like residue, he was only burning pine and not very dry. over here we use a nylon sweeping head so as not to damage the liner.
johnluc

 

[henton49er]

I agree with the general consensus on here that flues from woodburners need to be swept. Not only will the resinous products from woods such as pine build up quickly inside the flue, the flue itself will be attacked by the residues and even stainless steel will gradually be eroded away.

As noted elsewhere, it is important to have a record of the chimey sweeping dates in the event of an insurance claim for a chimey/flue fire.

 

[tekno.mage]

We burn wood and sweep our chimneys three times in a season - once at the start of Autumn, again round about now and again in about March. Once a year was not enough to prevent a chimney fire (although it was a harmless if spectacular event as we live in an old stone farmhouse wih no wooden beams anywhere near the chimneys). The black tar-like or hard residue that has been mentioned is called creosote and it's that which catches fire. Burning a lot of softwood or damp wood makes it build up quicker, but you should still sweep your chimney regularly even if you only burn dry hardwood.

 

[Steve Maskery]

Re the temperature.
Soot and smoke is essentially carbon, which is heavier than air. The only reason it goes upwards is that it carried by warm, rising air. That updraght needs to be enough to overcome gravity, and that doesn't happen until it gets hot. Hence the downdraught when freshly lit.
S

 

[Rob Bacon]

As already said a cold or damp flue will not pull that well it normally reaches temperature after 5-10 minutes, but do make sure that you have it swept regularly also make sure that a flue flow test and a spillage test is carried out at the same time. their should also adequate ventilation for the wood burner burn correctly and safely.

Rob

 

[Alex]

You probably do but just in case. (hammer)
Have a sealed carbon monoxide alarm in the room with burner and another in any room the chimney passes through exiting house. The prior is a requirement the latter a recommendation.

Kym/Tekno- does you flue have a liner and is it insulated?