Sweeping the chimney.

Dieselman

How often do you really do it?

I have read all the bumf of every 12 months at least or twice a year if it's used more often but really how often do you do it?

My mate says his is used approx 7 months and he swept it once in 8 years loads came down but there is no need to sweep as often.

I bought my own rods and the brush and had a go before it was lit since it's been fitted 8 months there was some swept up by the ash vac.

For peace of mind and the enjoyment of doing it i'm doing mine at least once per year.:D

Greenfires

There's no one answer. So much depends on the stove/chimney/draught/way the stove is operated/fuel you use and so on.

The "official" guidelines say a woodburning stove should be swept every three months "when in use". The trouble is that guidelines such as this have to cater for worst case scenarios as well as those people operating stoves properly and burning decent (ie dry) fuel. If you try and slumber burn a stove 24/7 using wet wood you can fill a liner in 3 months - I've seen it more than once. Having said that, of the hundreds of stoves I sweep every year, I'd say there are perhaps two or three that need looking at more than once a year - and in both cases, it's them doing stuff wrong rather than any problem with the appliance or the flue. Burning wet wood is the classic - but I've also had a couple of problem stoves where they've been burning housecoal, and as well as some very thick deposits in the flue, they've blocked the mesh on the cowl with thick soot, effectively sealing the chimney.

The other thing of course is that it's all very well your mate saying they don't need doing that often. There are over 10,000 chimney fires every year in the UK and practically ALL of them were preventable - this would kind of suggest there might be a flaw in his argument!. Been to a few myself - one of which was in the house of someone high up in the fire brigade - who often run campaigns to get people to get their chimneys swept! There's also the issue of CO poisoning of course - there's much less risk from a well maintained chimney. Given that many people will pay the window cleaner a couple of hundred quid over the year, a few quid for a chimney sweep to help ensure your safety seems quite cheap!
Lastly - a chimney sweep will use the correct gear for the job - there are all sorts of different rods and brushes for different applications. I've been to a job only this morning where two restaurants have ended up having to have chimneys re-lined after someone thought it would be a good idea to do it themselves, and knackered the liners using the wrong sort of gear for the job! Most chimney sweeps get a couple of calls at least every year to go and get lost brushes out of chimneys where the homeowner has assumed it's "just sticking a brush up and wriggling it about a bit" And we always charge extra for those!

Little_Vics

Every year for us. We had a chimney fire last year when a bird's nest fell down the chimney and blocked it.

We had it swept last week and the chap bagged up 3 (yes, 3) bin bags of twigs/nesting materials from within - and that's despite it being capped!

OH will go up on a ladder at some point to see what's going on. Stupid birds.

Greenfires

I had a stuffed full builders bulk bag of nest out of a chimney last year where the customer told me "we cleared a nest earlier, but you may as well give it a quick sweep as you never know if there might be a bit left somewhere"

Hmmm....!

A._Badger

I think Greenfires is exactly right about how unpredictable it is. I have mine swept once a year and very little comes out - but I use decent quality smokeless and dry wood and I tend to run it flat-out. Heaven forbid if you used housecoal and tried to get away with annual sweeping, or if you slumbered wet wood!

Dieselman

Thanks all.:j

My wood is less than 16% and i use smokeless the better quality stuff he uses house coal but his is a open fire and he uses wood.

Lately seen a increase of house coal been burned a few around here with the black stuff coming out the chimneys.

Greenfires

There's no major problem with housecoal on an open fire - well pollution/sustainability issues aside. There's a lot more draught going up a chimney serving an open fire than one serving a stove - that's why smoke coming from a stove chimney always looks "lazy". This roaring draught will go some way to keeping the chimney clear of any really fluffy deposits - they just get blown away sort of thing. Older people may well remember getting "smuts" on the washing when it hung on the line in areas burning a lot of coal.

A._Badger

Greenfires wrote: »

There's no major problem with housecoal on an open fire - well pollution/sustainability issues aside. There's a lot more draught going up a chimney serving an open fire than one serving a stove - that's why smoke coming from a stove chimney always looks "lazy". This roaring draught will go some way to keeping the chimney clear of any really fluffy deposits - they just get blown away sort of thing. Older people may well remember getting "smuts" on the washing when it hung on the line in areas burning a lot of coal.

I've often wondered about this. As the gasses in a liner are moving through a smaller diameter pipe and they are a lot hotter, why do people think they move more slowly? Have we any actual measurements to show this?

Just curiosity...

Greenfires

Because the only draught that can get up the chimney from a stove is having to pass through the air vents in it - the combined area of which will be a fraction of the throat area of an open fire. This is assuming the stove is properly installed with a sealed register plate etc. A stove going into an open (ie unlined) chimney is even more pronounced - like a fast flowing stream carrying loads of sediment flowing into a wide open lake - all the sediment drops out as it enters the lake and slows down.

A._Badger

Greenfires wrote: »

Because the only draught that can get up the chimney from a stove is having to pass through the air vents in it - the combined area of which will be a fraction of the throat area of an open fire. This is assuming the stove is properly installed with a sealed register plate etc. A stove going into an open (ie unlined) chimney is even more pronounced - like a fast flowing stream carrying loads of sediment flowing into a wide open lake - all the sediment drops out as it enters the lake and slows down.

I have a dim memory of school physics (not to mention steam boiler design) suggesting that this is unlikely and that the smaller area presented by the vents and grate, the intense heat and a smaller flue would result in faster moving gasses - but it was absorbed a long time ago and I could be wrong.

I'd still like to see some reliable figures, as I would with quite a lot of stove legend and lore.

alleycat`

I know fluids in a narrow pipe move faster, but under less pressure than fluids in a wider pipe.

I'm not sure that it will directly impact flow rate in terms of a single pipe.

A steam boiler with multiple narrow pipes would probably out perform a single fat pipe in terms of flow rate through the boiler whilst making up for the lost pressure.

Not sure how that applies to chimneys or if that is even correct.

I'd have asked my neighbour as he designed steam locos but sadly he passed away a couple of years ago.

He was still designing the ones that you can sit on until a few weeks before he died.

Probably the most interesting person i've ever met.

He built a scale model landrover series I for his grandkids (complete with battery drive from wheelchair) and, more oddly, a working scale model of the salisbury cathedral clock mechanism.

Anyway i digress. I have my chimney swept annually in August after most of the birds have stopped nesting (per the original post).