I may have a line on a decent catalyst woodstove.
I've been burning wood for the last 7 years, but with an Avalon Rainier

non-catalyst model.
We're adding a second stove and I have a line on an older Silent Flame
model with a catalytic combustor.
My question is - how does a catalyst stove perform on an overnight
burn?
I understand there needs to be a certain temperature to light-off the
combustor, but what happens later when the fuel runs low while the
combustor is still engaged?
I know I will be doing overnight burns and want to be sure that a
catalyst stove will perform well under those conditions.


I'd like to hear from anyone who has such a stove and uses it for heat
24-7.

On 8 Nov 2005 21:38:00 -0800, northcountry wrote:

We're adding a second stove and I have a line on an older Silent Flame
model with a catalytic combustor.

Don't have that model - have Woodstock Soapstone Classic w/catalytic burner.

My question is - how does a catalyst stove perform on an overnight
burn?

My experience has been very good. Get plenty of heat, and if using hardwood,
a good long burn - approx 8-9 hours or so overnight. I also burn pine (well
cured, of course), but the burn time is a good bit less and I try to use
hardwood overnight.

I have a sweep come annually (roof is too steep for my comfort - always
cleaned the flue myself at the old house w/non-combustor stove) and he always
says that the flue is in good shape. He does a thorough job but doesn't have
much to get out.

I understand there needs to be a certain temperature to light-off the
combustor, but what happens later when the fuel runs low while the
combustor is still engaged?

Burning with a combustor takes a little getting used to, but is not
difficult. I highly recommend a combustor probe of some kind rather than a
surface mount thermometer to monitor the combustor. As I understand it, most
stoves have a hole for such a probe.

The first year I had my stove I was using a surface mount thermometer and
wound up with excessive creosote (compared to now, not compared to a
non-combustor stove) because I was not able to tell (due to the thickness of
the soapstone I was measuring the temp of) if the combustor had lit-off or
gone out for a while after I engaged it. It doesn't always light-of the first
try - depends on density of the smoke and exactly how hot the combustor and
smoke is. A probe measuring the gasses coming out of the combustor will let
you know when you should engage the combustor and you know almost immediately
if the combustor lit-off or if you need to disengage it and let it heat up a
little more. Using the surface mount thermometer caused my learning curve to
be greatly exaggerated. Once I started using the probe, it didn't take long
to figure out how to make things work properly. That may be different on an
all-metal stove - never had one of those with a combustor in it.

Yes, the combustor needs a certain light-off temperature. I use an electronic
probe made by Condar (model 9-86, see http://www.condar.com/meters.html for
more info) to determine when the proper temp is reached and to make sure that
the combustor is burning after engaging. If the temp is borderline on
light-off temp then the combustor may not stay lit the first try. It also
provides an excellent indicator of when to reload - if you see the temp
approaching the light-off temp, you can reload and not have to worry about
the combustor going out - or if it does, it will light-off almost immediately
after you reengage it.

One big thing to remember is not to get the combustor too hot too fast. If
you get a roaring fire going as soon as possible, you'll probably crack your
combustor. Should be some warning about that in the stove docs. Build up the
fire over about 45 minutes or an hour to light-off temp. Refilling isn't so
critical unless you've let the fire die back really low.

When the fuel runs low toward the end of a burn, there is not much creosote
generating material left - I'm sure you've noticed that there isn't any or
very much smoke from the coals in your other stove in the morning. Since
there isn't much smoke, there isn't a problem with clogging the combustor -
that would occur if you don't reach the light-off temp and engage the
combustor anyway. Regardless, any buildup from the end of a burn is cooked
off when you build up the fire in the morning and will accumulate (what isn't
forced out by the smoke flowing through the combustor) in the honeycomb as
fine powder.

I usually blow out the combustor with my shop vac every 4-6 weeks when I'm
burning 24-7 - before I got the shop vac I just blew it out using a piece of
3/8" hose and lungpower. Be careful with the combustor when cleaning, they
are rather fragile and not so cheap. I changed my combustor after 4 years (I
figure that my mis-use of the combustor the first year really limited it's
life) - YMMV.

I know I will be doing overnight burns and want to be sure that a
catalyst stove will perform well under those conditions.


I'd like to hear from anyone who has such a stove and uses it for heat
24-7.

My heating season isn't long - Northwest Ga - but I do use the heater 24-7
once cold weather sets in unless it gets really warm outside. I try to take
advantage of warmer days to let the fire die to clean the combustor.

HTH

Later, Mike
(substitute strickland in the obvious location to reply directly)
-----------------------------------


Please send all email as text - HTML is too hard to decipher as text.

I bought a new high efficiency, hand fired Harman wood/coal stove a few
years back. What is uses is a second set of air vents, in the door,
below the glass, that are constantly open- they are just slits. This
air enters the firebox above the fuel, and causes further combustion
and a more complete burn, and less chimney emissions. It's really an
emission control design- but what I found was, it's HIGHLY EFFICIENT at
burning coal and wood. It squeezes every last available BTU out of the
fuel- and also has a built in eletric fan to blow the heat out of the
top through vents. It is hand stoked, so I have to load it with coal
daily, and rake it down, and empty ashes about every 2-3 days. What is
amazing about this stove is, it heats my home using only 2.5 tons of
coal annually. I've been burning coal now for 12 years, and for $250
it heats the house all winter- through some very frigid Pa. USA
winters. Typically I burn it from November to April, sometimes into
May. With the recent spike in fuel costs, 3 ton of coal cost me $375
this year, but I won't even burn all that.

Another interesting fact- the draft control is a large knob that is 6
turns full out- I burn this stove at only 3/8 of a turn out with coal
and it stays lit indefinitely and heats the house, as long as the fire
is serviced. I have never had to open the draft further than 3/4 turn
out, even during 20-30 below zero days. The stove basically burns 40
pounds of coal daily, on the coldest days- on warmer days in the
30-40's, one bucket (40 pounds) will last 2-3 days. I can't believe
how efficient it is.

If the draft is opened up beyond 3/4 turn, and the fan turned on, we
are opening upstairs windows to let heat OUT of the house in the dead
of winter.

By comparison, I lugged 6 heaping truckloads of wood, loaded to the cab
roof, full size F-150 8-ft box, to my relatives last month- they burn
wood. It cost us $40 in gas to haul that wood- then it had to be split
and stacked by them.

For the money, I'd prefer to spend the $300 and burn coal- the work
involved transporting, splitting, and stacking the wood outweighs any
cost savings, in my case.

My main system is electric baseboard, which I keep turned off all year.

Thanks Mike,
One note - from what I've read, you should never "blow-out" a combustor
to clean it.
I read in two separate places that vacuuming is the only recommended
method for clearing obstructions. Not sure if it matters, providing
your careful about it, but I thought I'd pass it along...
One other question - have you had to replace the combustor yet?
I anticipate having to replace mine as soon as I take possession of the
stove (I bought it from a neighbor who had it for 15 years).
I found a replacement for $66 including shipping at
www.stovecombustors.com - not as bad as I thought.

Whoops - i just read the part where you changed it out after four years
- ignore that question ;-)

On 9 Nov 2005 08:54:26 -0800, northcountry wrote:

One note - from what I've read, you should never "blow-out" a combustor
to clean it.
I read in two separate places that vacuuming is the only recommended
method for clearing obstructions. Not sure if it matters, providing
your careful about it, but I thought I'd pass it along...

Vacuum, blow - both move some air through the honeycomb to clear the powder.
You should be careful anytime you're doing something with the combustor it's
pretty fragile. Not to be argumentative, but to provide you with the most
info possible, I went to Woodstock Soapstone Company and looked up the tips
on combustor care. See
http://www.woodstove.com/pdffiles/Ca...tor%20Tips.pdf at the
bottom of page 2 right hand column. It says that LOW pressure compressed air
is ok and that canned air for cleaning computers is fine.

I would think that blowing or vacuuming with a shop vac would generate
similar air flow rates - can't get the vac nozzle against the combustor on
the sides with the openings anyway, unless I take it out of the cast iron
cover and then I'd have to replace the gasket that seals around the
combustor. If you'd like to actually see what I'm talking about, I'd be happy
to take a couple of pix showing how the combustor is mounted and send them to
you - send private email (see sig) if you do as this is not a newsgroup for
pix.

BTW, that document may answer any questions you may still have about
combustors. Although it's for Woodstock stoves in particular, the gist of it
should apply to any stove with a combustor. Didn't occur to me or I would
have sent the URL with my earlier reply.

One other question - have you had to replace the combustor yet?

You should also note that I had misused my combustor the first season due to
my lack of knowledge about how they work and the problem measuring the temps
through the soapstone stovetop (if you are unfamiliar with this type of
stove, see http://www.woodstove.com/pages/classic.html). The instructions say
to measure the temp in the center of the left-hand panel on the top - they
provided a thermometer that would normally stick onto a metal stove with a
built-in magnet. Not the best type of thermometer, even for a metal stove,
from what I've read.

The combustor would probably have lasted longer - I expect the new one to
last a good bit longer.

The combustor temp probes also help determine when it's time to change the
combustor by letting you know that the combustor isn't getting up to the high
temps that it normally runs at - gives you time to get a new one before the
old one completely fails.

I anticipate having to replace mine as soon as I take possession of the
stove (I bought it from a neighbor who had it for 15 years).

If it hasn't been changed in that amount of time, I'm sure that it is no
longer working. The above mentioned URL says that a combustor will last 4-5
years. I figure I should get a year or two more from it since my burn season
is short - time will tell.

I found a replacement for $66 including shipping at
www.stovecombustors.com - not as bad as I thought.

No, not too expensive, but still something you wouldn't want to shell out
unnecessarily.

Later, Mike
(substitute strickland in the obvious location to reply directly)
-----------------------------------


Please send all email as text - HTML is too hard to decipher as text.

Universal Mind, if I may ask , where in PA do you buy 3 tons of coal
for $375 ?
Is it bagged or loose ?

Thanks in advance