Woodburner Draw

[SpecialK]

You need a really good camera and light to inspect the flue. I tried with a usb one (£25) but the amount of soot and darkness (even with a torch strapped to it) made the image very poor!

When I open my woodburner door and its cold in there I know its not drawing correctly. I normally crack a window and it goes nice and warm in there as it pulls air up the chimney. Well worth getting the liner inspected first though as above to rule that out...

 

[subzero]

Hi all

I decided to shin up into the loft, as I recalled that the HETAS installer struggled to get the liner down originally, and had to remove some bricks in various places in the chimney breast (downstairs as well but plastered over afterwards). The bricks in the loft were never cemented back in place, so I removed them to have a butchers hook at the liner.

I was actually looking for an acute bend in the liner somewhere, that might be stopping the brush going the full distance.

As you can see it looks a bit grubby but perhaps at this level, near to the pot, this external appearance is what might be expected after 10 years of service?

 

[Lower]

That looks like it’s been leaking.

 

[subzero]

Sounds expensive.

 

[Lower]

It looks like you have creosote on the outside of the flue and on the inside of the chimney, which means the flue has been leaking and flue gases have been condensing on the outside of the flue and the inside of the chimney.

If that's the case, then i assume that a new liner is the only fix.

 

[cwhaley]

I would agree with others in saying that that flue looks like its broken somewhere and is leaking gasses. If it's broken that is most likely why you're struggling the light the fire as cold air is being drawn down the chimney.

A test you could do is leave a hair dryer on warm/hot pointing into the stove so that the hot air is taken up the flue. Then light your stove and see if it's easier to light. If nothing is drawn back down into the room then problem identified.

 

[subzero]

I would agree with others in saying that that flue looks like its broken somewhere and is leaking gasses. If it's broken that is most likely why you're struggling the light the fire as cold air is being drawn down the chimney.

A test you could do is leave a hair dryer on warm/hot pointing into the stove so that the hot air is taken up the flue. Then light your stove and see if it's easier to light. If nothing is drawn back down into the room then problem identified.

Questions:

How could the liner break through normal use? I know from experience that these specific liners are actually quite difficult to perforate, even with a cutting tool.

Unless it was damaged during the original install and the installer either didn't realise, or kept quiet about it. But then surely a smoke test after the installation would have proven whether there were any leaks?

When we tried to light it (having swept the flue), and the same issues were happening, we removed the air control, taped a cylinder of cardboard to a hairdryer, and placed this over the aperture, forcing air into the mix. Once the combustibles had ignited and the fire got going, things improved greatly.

We will try your suggestion, warm the flue first then attempt to ignite a fire as normal, and see what happens.


Thanks again to all for your input and advice at this point, much appreciated.

 

[cwhaley]

Questions:

How could the liner break through normal use? I know from experience that these specific liners are actually quite difficult to perforate, even with a cutting tool.

Unless it was damaged during the original install and the installer either didn't realise, or kept quiet about it. But then surely a smoke test after the installation would have proven whether there were any leaks?

They can break due to a number of reasons. I'd wager that yours' is has began corroding as they do after ten years of burning different materials -- many only come with a 10 year guarantee anyway for this very reason. No matter how cleanly we try to burn materials, the resulting gases are damaging in varying degrees. Also, when it was put down the chimney (with difficulty as you say) it could have suffered damaged then which accelerated the build up to the potential breach in the liner you have now.

The damage may have been small enough as to not show during the smoke test.

 

[Burnerman]

Now that you have the liner exposed, why not pop a smoke pellet in and see what happens?
Surely if the liner was perforated, the loft void would stink of smoke......the bricks aren't cemented in?
John

 

[subzero]

Now that you have the liner exposed, why not pop a smoke pellet in and see what happens?
Surely if the liner was perforated, the loft void would stink of smoke......the bricks aren't cemented in?
John

Good tip, thanks.

Funny you should mention that... in the past we've noticed a smell of smoke in both the loft *and* the front bedroom (non-functional cast iron fireplace in situ)

 

[Burnerman]

Perforated liner or not, I still think there's a blockage at the top of the flue.
John

 

[lostinthelight]

was actually looking for an acute bend in the liner somewhere, that might be stopping the brush going the full distance.

So are you now saying that you can't get the end of the rods all the way up and out the top but have swept it?

 

[subzero]

So are you now saying that you can't get the end of the rods all the way up and out the top but have swept it?

That's correct.