Flue staining

[Andregrante]

Hi all,
My mother got a new stove and ss flue fitted in the summer but has experienced a lot of staining on the flue. It looks like the gasses are condensing at the top of the flue and the resulting goo is running down the outside.
Ive checked the following :
She's using smokeless stove coal
The fire is burning well with good draw and heat
There's no air leaks anywhere

Stove is a Stanley oisin

Can anyone help , pic attached (the clean section at the top had just been fitted by the installer in an attempt to fix the problem it's now in the same state as the rest)
Thanks

 

[bholler]

Hi all,
My mother got a new stove and ss flue fitted in the summer but has experienced a lot of staining on the flue. It looks like the gasses are condensing at the top of the flue and the resulting goo is running down the outside.
Ive checked the following :
She's using smokeless stove coal
The fire is burning well with good draw and heat
There's no air leaks anywhere

Stove is a Stanley oisin

Can anyone help , pic attached (the clean section at the top had just been fitted by the installer in an attempt to fix the problem it's now in the same state as the rest)
Thanks

Coal is nasty stuff. Not sure what exactly is in smokeless but i am sure it isnt much better than regular coal. We always see staining like that on coal chimneys here.

 

[Kevin Weis]

The sections aren't connected in reverse are they? Should be that anything running down the inside of the pipe stay's inside the pipe, no? Otherwise, coal has sulfur in it. That could be what is running down the pipe from the top. Even hard coal has it in there, just not near as much as soft. Smokeless coal, is that what they're calling hard coal now? Hard coal once ignited has no smoke anyways. I run a small coal stove on bitter days as a back up. Maybe six times a year. If anyone wants to know more there's another stove forum for coal burning on the net.

 

[bholler]

The sections aren't connected in reverse are they? Should be that anything running down the inside of the pipe stay's inside the pipe, no? Otherwise, coal has sulfur in it. That could be what is running down the pipe from the top. Even hard coal has it in there, just not near as much as soft. Smokeless coal, is that what they're calling hard coal now? Hard coal once ignited has no smoke anyways. I run a small coal stove on bitter days as a back up. Maybe six times a year. If anyone wants to know more there's another stove forum for coal burning on the net.

Smokeless is a product from europe. I am not sure what it is made of. And no anthrecite has no visible smoke. But there are still lots of emissions. And it is very corrosive.

 

[Andregrante]

Thanks for the replys guys, flue sections are definitely the right way up, the "coal" is this stuff...
Hi Lite
Hi Lite is a manufactured smokeless ovoid, recommended for burning in cookers, stoves and room heaters. With suitable and controlled air flow from your stove Hi-Lite will burn for long periods leaving minimum ash. Hi Lite is also known as EcoBrite.

Suitable for: Multi Fuel Stoves & Cookers

 

[begreen]

They looks like the charcoal briquettes used for BBQ.

Kingsford Charcoal, for example, by far the most popular brand in the US, is made up of bits of charcoal, coal, starch (as a binder), sawdust, and sodium nitrate (to make it burn better). For the same reason that SPAM is cheaper than a whole ham, briquettes are cheaper to make than all-wood charcoal.

 

[Andregrante]

They looks like the charcoal briquettes used for BBQ.

Kingsford Charcoal, for example, by far the most popular brand in the US, is made up of bits of charcoal, coal, starch (as a binder), sawdust, and sodium nitrate (to make it burn better). For the same reason that SPAM is cheaper than a whole ham, briquettes are cheaper to make than all-wood charcoal.

This stuff is one of the most expensive options on the market here, I've burned it myself previously with no issues. I'm burning almost exclusively wood these days though