On Sun, 23 Dec 2007 12:41:40 +0000, Anna Kettle wrote:

Thats interesting, so it is not essential for building regs to line a
chimney before a stove is put in.

That's right but the difficulty arises in proving that the existing
chimney meets regs without a liner, so an installer would be unsure to
sign off a flue installation plate.

I have friends who have a big old
chimney very similar to mine, they didnt line their chimney and it
works perfectly well with a woodburner

As did many chimneys before the new regs came in in 2000.

I fitted my wood burner (small Jotul) 30 years ago and it vents, via a
short 150mm enameled steel flue into a 220mm concrete lined chimney and
works fine. Doing the same job now I would probably opt for a 904
stainless 150mm liner with vermiculite insulation.

AJH

On Sun, 23 Dec 2007 14:05:32 +0000, andrew heggie
wrote:

On Sun, 23 Dec 2007 12:41:40 +0000, Anna Kettle wrote:

Thats interesting, so it is not essential for building regs to line a
chimney before a stove is put in.

That's right but the difficulty arises in proving that the existing
chimney meets regs without a liner, so an installer would be unsure to
sign off a flue installation plate.

I shall be installing it myself so I dont care about that

I have friends who have a big old
chimney very similar to mine, they didnt line their chimney and it
works perfectly well with a woodburner

As did many chimneys before the new regs came in in 2000.

I fitted my wood burner (small Jotul) 30 years ago and it vents, via a
short 150mm enameled steel flue into a 220mm concrete lined chimney and
works fine. Doing the same job now I would probably opt for a 904
stainless 150mm liner with vermiculite insulation.

You are another person who would go for the insulated liner then ...

Anna
~ ~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repair and conservation
/ ^^ \ // Freehand modelling in lime: overmantles, pargeting etc
|____| www.kettlenet.co.uk

On Sun, 23 Dec 2007 16:45:22 +0000, Anna Kettle wrote:

You are another person who would go for the insulated liner then ...

For preference, yes and to get the flue signed off yes also. There can be
efficiency improvements as it means you can reject flue gas at a
lower temperature and still have an effective chimney, but the woodburner
would need to be designed with this in mind. In fact there are all sorts
of reasons why an insulated flue of the correct cross section is better,
the only drawback is that the flue tends to cost far more than the wood
burner.

Some types of woodburner, masonry stoves, actually use a massive fireplace
to absorb heat and then release it into the room slowly, these burn at a
very high power and wouldn't work with an insulated flue as they depend on
the flue passage as a heat exchanger, a bit like roman hypercausts.

AJH

andrew heggie wrote:
On Sun, 23 Dec 2007 16:45:22 +0000, Anna Kettle wrote:

You are another person who would go for the insulated liner then ...

For preference, yes and to get the flue signed off yes also. There can be
efficiency improvements as it means you can reject flue gas at a
lower temperature and still have an effective chimney, but the woodburner
would need to be designed with this in mind. In fact there are all sorts
of reasons why an insulated flue of the correct cross section is better,
the only drawback is that the flue tends to cost far more than the wood
burner.

Some types of woodburner, masonry stoves, actually use a massive fireplace
to absorb heat and then release it into the room slowly, these burn at a
very high power and wouldn't work with an insulated flue as they depend on
the flue passage as a heat exchanger, a bit like roman hypercausts.


Odd that. as the aga which is essentially that, was specified for an
insulated flue. Albeit of a lower spec than the wood burner.


AJH

On Sun, 23 Dec 2007 18:42:00 +0000, The Natural Philosopher wrote:

Some types of woodburner, masonry stoves, actually use a massive fireplace
to absorb heat and then release it into the room slowly, these burn at a
very high power and wouldn't work with an insulated flue as they depend on
the flue passage as a heat exchanger, a bit like roman hypercausts.


Odd that. as the aga which is essentially that, was specified for an
insulated flue. Albeit of a lower spec than the wood burner.

The aga is massive but its flue is just a means of exhausting the gases,
there's no scope for getting more heat out of the flue gases so they
should not be cooled further, and as they are already quite cool they can
use a cheaper liner if fired on smokeless fuel, gas or oil. The aga I
mentioned earlier that would not draw simply did not have enough heat in
the flue gases to warm the massive chimney it was exhausting into, as well
as the other problems I mentioned.

The masonry fire is actually built into the chimney breast that then
becomes a "radiator" and thermal store, so the flue reaches high
combustion temperatures but is cooled by the massive structure. I'm not
familiar with them but I would expect the flue gases to actually leave the
top at a similar temperature to a conventional wood stove 150C.

AJH

andrew heggie wrote:
On Sun, 23 Dec 2007 18:42:00 +0000, The Natural Philosopher wrote:

Some types of woodburner, masonry stoves, actually use a massive fireplace
to absorb heat and then release it into the room slowly, these burn at a
very high power and wouldn't work with an insulated flue as they depend on
the flue passage as a heat exchanger, a bit like roman hypercausts.

Odd that. as the aga which is essentially that, was specified for an
insulated flue. Albeit of a lower spec than the wood burner.

The aga is massive but its flue is just a means of exhausting the gases,
there's no scope for getting more heat out of the flue gases so they
should not be cooled further, and as they are already quite cool they can
use a cheaper liner if fired on smokeless fuel, gas or oil. The aga I
mentioned earlier that would not draw simply did not have enough heat in
the flue gases to warm the massive chimney it was exhausting into, as well
as the other problems I mentioned.

The masonry fire is actually built into the chimney breast that then
becomes a "radiator" and thermal store, so the flue reaches high
combustion temperatures but is cooled by the massive structure. I'm not
familiar with them but I would expect the flue gases to actually leave the
top at a similar temperature to a conventional wood stove 150C.


No. You can put your hand on the stove pipe. It's nearer 60-70C. For an aga.

VERY efficient heater. More so than a condensing boiler IMO.



AJH

On Mon, 24 Dec 2007 09:13:19 +0000, The Natural Philosopher wrote:

No. You can put your hand on the stove pipe. It's nearer 60-70C. For an aga.

I was comparing the chimney outlet of a masonry stove with that of a
conventional stove, not agas which I had earlier said had low temperature
flue gases,


VERY efficient heater. More so than a condensing boiler IMO.

:-) I've left my personal opinions of agas out of this....

AJH

On 24 Dec, 09:13, The Natural Philosopher wrote:
andrew heggie wrote:
On Sun, 23 Dec 2007 18:42:00 +0000, The Natural Philosopher wrote:

Some types of woodburner, masonry stoves, actually use a massive fireplace
to absorb heat and then release it into the room slowly, these burn at a
very high power and wouldn't work with an insulated flue as they depend on
the flue passage as a heat exchanger, a bit like roman hypercausts.

Odd that. as the aga which is essentially that, was specified for an
insulated flue. Albeit of a lower spec than the wood burner.

The aga is massive but its flue is just a means of exhausting the gases,
there's no scope for getting more heat out of the flue gases so they
should not be cooled further, and as they are already quite cool they can
use a cheaper liner if fired on smokeless fuel, gas or oil. The aga I
mentioned earlier that would not draw simply did not have enough heat in
the flue gases to warm the massive chimney it was exhausting into, as well
as the other problems I mentioned.

The masonry fire is actually built into the chimney breast that then
becomes a "radiator" and thermal store, so the flue reaches high
combustion temperatures but is cooled by the massive structure. I'm not
familiar with them but I would expect the flue gases to actually leave the
top at a similar temperature to a conventional wood stove 150C.

No. You can put your hand on the stove pipe. It's nearer 60-70C. For an aga.

VERY efficient heater. More so than a condensing boiler IMO.

AJH

I was dubious about your claim that agas are efficient, so I did a
little calculation. Assuming that a solid fuel aga requires the same
amount of energy whatever the fuel, aga suggest you need 47.5kg of
solid fuel to get 220kWh. Unless I've done something wrong, that makes
it about 70% efficient. That's pretty impressive for a slow burning
cooker!

T

On Mon, 24 Dec 2007 09:15:54 +0000, Huge wrote:

On 2007-12-23, andrew heggie wrote:

the flue passage as a heat exchanger, a bit like roman hypercausts.

Not a flame(!), but it's "hypocaust".

No it's christmas ;-) and I think you are right but:

Hypocaust would be the bit under the floor, I think the flue passages also
ran up the walls and I have seen a square flue wall tile described as a
hypercaust but that equally may have been wrong. I was describing a
vertical chimney breast that was designed to absorb heat and then slowly
release it to the room.

I know the derivation of hyper and hypo but whence "caust"? Caustic is
used to describe alkaline substances that burn. I'll have to remeber to
look one day.

AJH

Hi,

Soot buildup could be much more of a problem with unlined chimneys.

So for professional installers, lined insulated chimneys have much
more butt covering potential in case the chimney gets neglected.

Once a chimney fire gets going I wonder if it's easier to stop with a
stove rather than an open fire.

Maybe worth getting the opinion of an experienced chimney sweep, who
may favour something that needs more sweeping, but could have some
good advice.

cheers,
Pete.

Pete C wrote:
Hi,

Soot buildup could be much more of a problem with unlined chimneys.

So for professional installers, lined insulated chimneys have much
more butt covering potential in case the chimney gets neglected.

Once a chimney fire gets going I wonder if it's easier to stop with a
stove rather than an open fire.

Slightly.

The trick is to put the fire out quickly with water, and then block
the chimney.

Ive used a bucket of water for the first, and a couple of newspapers
over an open fire face for the second. This is the 'approved' method.
With a stove although its slightly harder to put the fire out, its a
damn sight easier to starve the airflow. Shut all dampers and doors.



Maybe worth getting the opinion of an experienced chimney sweep, who
may favour something that needs more sweeping, but could have some
good advice.

Regularly used flues with wood need sweeping annualy. maybe more with
unlined ones.

The one that I set alight three times in a row, was an open wood and
coal burner that had been swept about 18 months previously, but was the
second source of heat in the house apart from a coal aga.


The other one was similar, but hadn't been swept for several years


cheers,
Pete.

wrote:
On Sun, 23 Dec 2007 18:47:07 +0000, The Natural Philosopher
wrote:

Once a chimney fire gets going I wonder if it's easier to stop with a
stove rather than an open fire.
Slightly.

The trick is to put the fire out quickly with water, and then block
the chimney.

Ive used a bucket of water for the first, and a couple of newspapers
over an open fire face for the second. This is the 'approved' method.
With a stove although its slightly harder to put the fire out, its a
damn sight easier to starve the airflow. Shut all dampers and doors.



There can be a lot of heat energy stored if you have good fire going
though whether its open or in a stove. It may be the approved method
but pouring a bucket of water onto a healthy hot pile of wood and ash
can produce an amount of steam whose affect in an enclosed room varies
from mildly alarming to enough to cause scalding.
ISTR that if that bucket held one gallon of water and it all turned to
steam it would take the space of about 1600 buckets.

For anyone who has to do it watch the hands and face.

You obviously have NOT done it.

The steam gets drawn up the roaring chimney.


G.Harman

On 23 Dec, 16:45, (Anna Kettle) wrote:
On Sun, 23 Dec 2007 14:05:32 +0000, andrew heggie

wrote:
On Sun, 23 Dec 2007 12:41:40 +0000, Anna Kettle wrote:

Thats interesting, so it is not essential for building regs to line a
chimney before a stove is put in.

That's right but the difficulty arises in proving that the existing
chimney meets regs without a liner, so an installer would be unsure to
sign off a flue installation plate.

I shall be installing it myself so I dont care about that

I have friends who have a big old
chimney very similar to mine, they didnt line their chimney and it
works perfectly well with a woodburner

As did many chimneys before the new regs came in in 2000.

I fitted my wood burner (small Jotul) 30 years ago and it vents, via a
short 150mm enameled steel flue into a 220mm concrete lined chimney and
works fine. Doing the same job now I would probably opt for a 904
stainless 150mm liner with vermiculite insulation.

You are another person who would go for the insulated liner then ...

Anna
* * * * * * ~ ~ * * * * * Anna Kettle, Suffolk, England *
*|""""| * *~ * * * * * Lime plaster repair and conservation
*/ ^^ \ // * *Freehand modelling in lime: overmantles, pargeting etc
*|____| * * * * * * * * * * * *www.kettlenet.co.uk

Dear Anna and Staffbull

1)
"The 2002 edition of Approved Document J of The Building Regulations
stipulates that any work that affects an existing chimney (ie fitting
a new stove or liner) or creating a new chimney now comes under
building control"
2)
"An existing chimney or a new flue or chimney installation must be
given a visual inspection to check that it is in good order, clear of
obstructions and is of a suitable size and type for the appliance you
plan to install. It may be necessary to sweep the flue (which should
always be done anyway before fitting a stove or lining a chimney) and
also, if necessary, to do a smoke test to check for gas tightness. "

As the wood burner is more efficient than on open fire I understand
from the literature (but may be wrong) that there is a much increased
risk of condensate of wood extractive then lining the flue and
becoming a fire risk in itself which is why double lined insulated
flues were invented and put in.

Generally speaking, I researched this and found that it would be at
LEAST twice the price of the stove to get it installed properly and
that I had to have a positive air supply which rather ruined my plans
for air tightness so I now have a normal fireplace and flue and keep
the flue closed when not in use

If you have access to lots of free wood and can store it on the
premises then go for it but it will cost and even if you do it
yourself you will need a helper to put in the liner and it will take
twice the time you think it will!
chris

On Sun, 23 Dec 2007 11:08:25 -0800 (PST), wrote:

As the wood burner is more efficient than on open fire I understand
from the literature (but may be wrong) that there is a much increased
risk of condensate of wood extractive then lining the flue and
becoming a fire risk in itself which is why double lined insulated
flues were invented and put in.

Generally speaking, I researched this and found that it would be at
LEAST twice the price of the stove to get it installed properly and
that I had to have a positive air supply
which rather ruined my plans
for air tightness

Can you elaborate? If the stove is small then regs say a vent is not
needed. Is that what you are talking about? My stove will largely be
for decoration and for enjoying the log fire and maybe boiling the odd
kettle so I thought I would just get a small stove, though I dont
think that putting in a vent will be difficult to do. Why did you want
it to be air tight?

BTW I have been told that the best places for a vent are high up in
the same room or low down and very close to the stove. Low down and
away from the stove produces draughts round the ankles

If you have access to lots of free wood and can store it on the
premises

Yes I can do that

then go for it but it will cost and even if you do it
yourself you will need a helper to put in the liner and it will take
twice the time you think it will!

Everything does! Especially things I have never done before and this
is a prime example. However I will have the advantage of a proper
scaffold in place cos I'm planning to repoint the stack and remove the
chimney pots at the same time

PS Anyone in the market for a couple of large Victorian chimney pots?

Anna


chris





~ ~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repair and conservation
/ ^^ \ // Freehand modelling in lime: overmantles, pargeting etc
|____| www.kettlenet.co.uk

Anna Kettle wrote:
On Sun, 23 Dec 2007 11:08:25 -0800 (PST), wrote:

As the wood burner is more efficient than on open fire I understand
from the literature (but may be wrong) that there is a much increased
risk of condensate of wood extractive then lining the flue and
becoming a fire risk in itself which is why double lined insulated
flues were invented and put in.

Generally speaking, I researched this and found that it would be at
LEAST twice the price of the stove to get it installed properly and
that I had to have a positive air supply
which rather ruined my plans
for air tightness

Can you elaborate? If the stove is small then regs say a vent is not
needed. Is that what you are talking about? My stove will largely be
for decoration and for enjoying the log fire and maybe boiling the odd
kettle so I thought I would just get a small stove, though I dont
think that putting in a vent will be difficult to do. Why did you want
it to be air tight?

BTW I have been told that the best places for a vent are high up in
the same room or low down and very close to the stove. Low down and
away from the stove produces draughts round the ankles

If you have access to lots of free wood and can store it on the
premises

Yes I can do that

then go for it but it will cost and even if you do it
yourself you will need a helper to put in the liner and it will take
twice the time you think it will!

Everything does! Especially things I have never done before and this
is a prime example. However I will have the advantage of a proper
scaffold in place cos I'm planning to repoint the stack and remove the
chimney pots at the same time

Ideal. if the flues are straight you simply drop it from the top in
sections, and hold it there with a plate on the stack top.

The problems happen when you have cranked over stacks.


PS Anyone in the market for a couple of large Victorian chimney pots?


5 years too late. ;-)
Anna


chris





~ ~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repair and conservation
/ ^^ \ // Freehand modelling in lime: overmantles, pargeting etc
|____| www.kettlenet.co.uk

wrote:
On 23 Dec, 16:45, (Anna Kettle) wrote:
On Sun, 23 Dec 2007 14:05:32 +0000, andrew heggie

wrote:
On Sun, 23 Dec 2007 12:41:40 +0000, Anna Kettle wrote:
Thats interesting, so it is not essential for building regs to line a
chimney before a stove is put in.
That's right but the difficulty arises in proving that the existing
chimney meets regs without a liner, so an installer would be unsure to
sign off a flue installation plate.
I shall be installing it myself so I dont care about that

I have friends who have a big old
chimney very similar to mine, they didnt line their chimney and it
works perfectly well with a woodburner
As did many chimneys before the new regs came in in 2000.
I fitted my wood burner (small Jotul) 30 years ago and it vents, via a
short 150mm enameled steel flue into a 220mm concrete lined chimney and
works fine. Doing the same job now I would probably opt for a 904
stainless 150mm liner with vermiculite insulation.
You are another person who would go for the insulated liner then ...

Anna
� � � � � � ~ ~ � � � � � Anna Kettle, Suffolk, England �
�|""""| � �~ � � � � � Lime plaster repair and conservation
�/ ^^ \ // � �Freehand modelling in lime: overmantles, pargeting etc
�|____| � � � � � � � � � � � �www.kettlenet.co.uk

Dear Anna and Staffbull

1)
"The 2002 edition of Approved Document J of The Building Regulations
stipulates that any work that affects an existing chimney (ie fitting
a new stove or liner) or creating a new chimney now comes under
building control"
2)
"An existing chimney or a new flue or chimney installation must be
given a visual inspection to check that it is in good order, clear of
obstructions and is of a suitable size and type for the appliance you
plan to install. It may be necessary to sweep the flue (which should
always be done anyway before fitting a stove or lining a chimney) and
also, if necessary, to do a smoke test to check for gas tightness. "

As the wood burner is more efficient than on open fire I understand
from the literature (but may be wrong) that there is a much increased
risk of condensate of wood extractive then lining the flue and
becoming a fire risk in itself which is why double lined insulated
flues were invented and put in.

Generally speaking, I researched this and found that it would be at
LEAST twice the price of the stove to get it installed properly and
that I had to have a positive air supply which rather ruined my plans
for air tightness so I now have a normal fireplace and flue and keep
the flue closed when not in use


In my case it was about a grand to do two pipes..one downstairs from the
aga, one upstairs from a wood burner.


The air feed was accomplished by a 4" p[ipe into the loft for the
latter, and a underfloor vent of tow 4" pipes for the aga.



If you have access to lots of free wood and can store it on the
premises then go for it but it will cost and even if you do it
yourself you will need a helper to put in the liner and it will take
twice the time you think it will!
chris