Talking of sintering...

[brassmonkey001]

I was chatting with a mate yesterday who told me about a house he was working at (he's a carpenter) and how, apparently, every 12 months someone had to go up on the roof with a hoe and chip away at the buildup of soot & tar in the chimney pot. Apparently it would go from say a 10" gap to a 2" gap over the course of one year.

Now, allowing for a degree of exaggeration or two, what would cause this buildup? Burning too much softwood and not enough hardwood? Burning other stuff i.e. rubbish like plastic?

I find it quite hard to believe a chimney would choke up so badly so quickly. What do you reckon?

[skyhuck]

Wet wood.

[County4x4]

It's perfectly possible mate, and there are quite a few possible reasons for it. Burning wet wood, running a stove in an unlined chimney, keeping the stove in overnight or leaving it slumbering for long periods - all these things will lead to a bigger build up of deposits. People often think that the stove installer who insists on fitting a liner is just trying to make more out of the job - but many of them are just covering their backs against unhappy customers a year or two down the line. An open fire and a modern stove are totally different animals, and this shows in the chimney. Even lined chimneys can end up with problems, often if they're long ones and the installer has not insulated the liner - the upper reaches of the chimney run much cooler with a stove, and with way less draught than an open fire - this is why smoke from stove chimneys often looks "lazy". That lazy smoke in a cold chimney has plenty of opportunity to condense on the walls.

 

Wet wood is probably the biggest culprit though - and I go to so many customers who reckon their wood is great, then you ask to test it and find it lives in a mouldy heap in a closed garage, and is off the scale on the moisture meter! As a chimney sweep, you'll have a pretty good idea about what they're burning and how they're doing it from the condition of the chimney, without even seeing the fuel store.

 

Have a look at this thread on the new Chimney Sweeps forum for some real beauties!

 

wall of shame pics - UK Chimney Sweeps

 

Cheers,

 

Andy

Edited May 31, 2011 by County4x4

[White Noise]

It's perfectly possible mate, and there are quite a few possible reasons for it. Burning wet wood, running a stove in an unlined chimney, keeping the stove in overnight or leaving it slumbering for long periods - all these things will lead to a bigger build up of deposits. People often think that the stove installer who insists on fitting a liner is just trying to make more out of the job - but many of them are just covering their backs against unhappy customers a year or two down the line. An open fire and a modern stove are totally different animals, and this shows in the chimney. Even lined chimneys can end up with problems, often if they're long ones and the installer has not insulated the liner - the upper reaches of the chimney run much cooler with a stove, and with way less draught than an open fire - this is why smoke from stove chimneys often looks "lazy". That lazy smoke in a cold chimney has plenty of opportunity to condense on the walls.

 

Wet wood is probably the biggest culprit though - and I go to so many customers who reckon their wood is great, then you ask to test it and find it lives in a mouldy heap in a closed garage, and is off the scale on the moisture meter! As a chimney sweep, you'll have a pretty good idea about what they're burning and how they're doing it from the condition of the chimney, without even seeing the fuel store.

 

Have a look at this thread on the new Chimney Sweeps forum for some real beauties!

 

wall of shame pics - UK Chimney Sweeps

 

Cheers,

 

Andy

 

Wow ace link

[WFWales]

Yes,Terrific link

 

I've just spent the weekend at the Woodfest in North Wales on our stand promoting the woodfuel industry in Wales. people really just dont realize the extent to which moisture content and a smoldlering fire left in overnight both knackers the chimney/flue and wastes their money by inefficiant burning of their fuel.

 

Burning wet wood is like putting £20 of diesel in your car and then pouring another £10 down the drain. Most people dont do it with Diesel, but loads of them do it with their woodfuel!

 

we are working to get some good material together for a new leaflet aimed at driving the point home.

 

Get a moisture meter and only burn wood with a max m/c of 25% - preferably below 20%.

make small fires burning them hot and fast to start, to get the max energy from the fuel.

Softwood is good to burn too

 

We are also promoting the HEATS SBAS quality scheme and helpong wood fuel producers through the certification process.

[Alycidon]

Yes,Terrific link

 

I've just spent the weekend at the Woodfest in North Wales on our stand promoting the woodfuel industry in Wales. people really just dont realize the extent to which moisture content and a smoldlering fire left in overnight both knackers the chimney/flue and wastes their money by inefficiant burning of their fuel.

 

Burning wet wood is like putting £20 of diesel in your car and then pouring another £10 down the drain. Most people dont do it with Diesel, but loads of them do it with their woodfuel!

 

we are working to get some good material together for a new leaflet aimed at driving the point home.

 

Get a moisture meter and only burn wood with a max m/c of 25% - preferably below 20%.

make small fires burning them hot and fast to start, to get the max energy from the fuel.

Softwood is good to burn too

 

We are also promoting the HEATS SBAS quality scheme and helpong wood fuel producers through the certification process.

 

 

 

Hard at 25% wont burn well at all, soft will though but not cleanly unless you get a real good fire going first. I have been into detail about the wet wood issue on a couple of occasions recently here so I wont repeat. What others have stated is correct.

 

No stove manufacturer recommends slumbering a stove overnight, on wood the low temps cause tars and several times the amount of soot. Another thing to be aware of is smokeless fuel and slumbering, almost all smokeless fuel is imported and has a very high sulpher content. Slumber that overnight on a low oxygen setting and the sulpher gas does not get combusted, it is very corrosive so when it gets into the flue it quickly corrodes a flue liner. No liner manufacturer warrants their liner for slumbering smokeless fuel.

 

The best advise you can give a stove owner is to fill it before bed and let it burn out on its usual setting, if its a half decent stove it will continue to radiate heat for some hours once the fire has died.

 

WF wales, pm sent,

 

A

 

A

[County4x4]

We only burn briquettes at home in our Squirrel - and never shut it down for overnight burning - it just gets left on whatever setting it was operating at during the evening. Nine times out of ten there will be enough left in the way of embers to relight the fire in the morning - we sell to quite a few narrowboat owners who love this as a feature as it's often their only source of heating, and they struggle to keep logs in all night unless they close the stove right down.

 

They don't have much in the way of chimney problems of course having only six feet or so out of the stove!

 

Andy

[WFWales]

Thanks Alycidon - I'll be in touch soon.

 

I spoke to another chap at the show who had his own intersting technique for "overnighting".

 

pop in some green ash into the stove, open the vents to get it roaring for a while, then close right down.

 

In the morning (apparently) you have a charcoal and all the nasty creasote oils etc covering the inside of the firebox.

 

Spark it up with a bit of paper and a couple of bits of kindling and off it goes like a rocket - burning all the nasty stuff, cleaning the glass again and getting hot very quickly.

 

No opportunity for me to try this in my gas heated flat.

 

Has any body heard of or tried this method? It was late at night at the beer tent and I had had a few sherberts so, um .....

 

he did emphasise that this only work with green ash

[Stereo]

If the firebox is full of gunk then the rest of it is likely to be as well and that won't burn off in a hot fire (until it finally catches of course and burns the house down).

 

We do overnight our Esse but we stack it out with good dry hardwodd and make sure it's burning very nicely before we close it up. It will stay in for a good 5 hours this way and we still have coals in the morning to get it fired up again with pallet wood.

[County4x4]

Regarding the "technique" for overnighting - considering that the stove will be the warmest bit of the system - if even that's covered in condensed crap, what on earth does he think is happening in the further, colder reaches of the chimney, or does he imagine that once the stove is closed down that nothing goes up the chimney?!

 

He sounds like the sort of chap who probably thinks having your chimney swept is unnecessary as well - and if he was one of my customers his bill would be a lot bigger than someone who knew what they were doing with their stove!!

 

I think I'll stick with my briquettes and not closing the stove down thank you!

 

Andy