Re-use 7 inch existing liner for new wood burning stove?

[ucoulddoit]

We've an open fireplace with a 7 inch twin wall stainless steel flexible liner which was installed about 20 years ago. Now looking at changing this to a wood burning stove and the spec is a 6 in twin wall liner. Just wondered if that's a minimum size and would the existing 7 inch liner be OK with a suitable transition piece at the bottom?

 

Andrew

[Dan Maynard]

Yes, flue sizes are minimum so will be fine. Otherwise nobody could ever connect to an unlined chimney.

[ucoulddoit]

12 hours ago, Dan Maynard said:

Yes, flue sizes are minimum so will be fine. Otherwise nobody could ever connect to an unlined chimney.

Thanks Dan

[Alycidon]

No. 

 

The installation of a stove is legally required to be certified as safe to use under the building regs.   whoever signs it off is personally legally liable,  if it leaks and as a result someone is killed via carbon monoxide poisoning he or she is facing a manslaughter charge which carriers a 10 year to life imprisonment term.      A 20 year old flue liner is past its best,    no installer will risk re using it and putting his name to a certification.   And no certification then if you have a fire its likely that your insurer will invalidate your policy.

 

A

[Dan Maynard]

Fair point, I considered size but not age.

[Steven P]

Back to the question, the size is OK, but to the latest answer it would be very good practice to test and clean any chimney before any installation works - you might find that the chimney is sound, you might find that it is full of holes.

 

If the liner is inside a sound chimney though even if the liner leaks the outer chimney will still be safe for fumes I think... but not sure any installer would go for that.

[ucoulddoit]

Thanks for the further advice. Was looking into this as one of two options. Minimal expense using what’s there with a Hobbit stove, suitable for an existing Victorian cast iron insert with tiles (fitted 20 years ago). Or, remove the insert, open up the ingle and have a larger stove with a new flue liner. I’ve had someone out to look at it and despite the cost of option 2, that’s probably the way I’ll go. Should ‘see me out’ and hopefully I’ll not be changing this again within the next 20 years.

 

Andrew

[Dan Maynard]

Can you sell the Victorian insert?

[ucoulddoit]

14 minutes ago, Dan Maynard said:

Can you sell the Victorian insert?

That's my thinking also. When I said to the stove installer I'd like to remove it before they start as I want it to be intact, he looked at me and laughed and reassured me they'd been doing it for 'decades' and if anyone could remove it in one piece, they could! So for once, I'll probably just take a back seat and leave this project to the experts. My wife likes to tease me that all my questions about 'details, etc.' probably just adds 10% to the cost! But it does help to get a good job done, instead of cutting a few corners.

 

Andrew

[Boot]

Alternatively, carefully break out the brick at the back of the fire,  drop a 6" flexible liner (best use 904 grade) attach x 2 135 degree bends and a straight length protruding at right height to connect to back of your choice of stove. Brick up around protruding flue and fit new extended hearth.  Fit stove.

 

If the wall is a gable end make sure you back fill with Leca to the top - if you use vermiculite it will compact over distance / time. Not insulating a gable end will cause draw issues relating to a cold chimney.

If its an internal chimney 3-4 bags of vermiculite would be more than enough.

 

Cheapest way with least disruption!