Ok, maybe a stupid question, is anyone burning Envi or other compressed sawdust bricks in a cat stove? For what it's worth, I burn them regularly in my Hearthstone without over firing or getting out of control.
Compressed Sawdust Bricks in a Cat Stove?
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stoveliker
Minister of Fire
You can burn such bricks in a cat stove, as long as there are no additives. I.e. just pure wood/shavings/dust.
That seems to be the case with Envi bricks.
In fact, some here advocate to buy a pallet of such bricks when buying a stove, because most people don't ahve enough dry wood stacked up when the stove is installed.
If you can control it well, it's not an issue. For a first time user of the bricks, I'd put in 3 or so, keep an eye on the stove to avoid it taking off, and get a feel for it. (Similar for e.g. burning untreated 2x4 cut offs.)
That seems to be the case with Envi bricks.
In fact, some here advocate to buy a pallet of such bricks when buying a stove, because most people don't ahve enough dry wood stacked up when the stove is installed.
If you can control it well, it's not an issue. For a first time user of the bricks, I'd put in 3 or so, keep an eye on the stove to avoid it taking off, and get a feel for it. (Similar for e.g. burning untreated 2x4 cut offs.)
ratsrepus
Minister of Fire
No problem as long as they are the highly compressed variety (NIELs, Homefires, Bio Bricks, Envi Bricks, etc.) and not the flakey cheapos.
BKVP
Minister of Fire
What is also paramount, is the source of raw materials. One brand tested from the PNW admitted their feedstock was often drift wood. The saline count was not favorable to any wood stove, let alone a catalytic wood stove. The good thing about NIEL's, they are not anywhere near the ocean! We have done very extensive, proprietary analysis of various (but not all) manufactured fuels. These lab studies have shown "most are organic" but some contained melamine and other materials that should not be burned in any stove.
Just read the label or call the company and ask about their source or feedstock to get an accurate answer. You will find they are generally very happy to speak with customers.
BKVP
That's a bummer. It would be good to identify those offenders. Some of the cheapo sawdust logs look like they were packed floor sweepings. Typically they expand badly on heating and leave a lot of ash. Homefires and NIELs are denser than water and stay solid down to the end of their burn.
BKVP
Minister of Fire
Of course I can't do that, But you can call them. When we did our sampling, we called and asked for samples. (I should have had a disclaimer that said.. "If you supply us a sample, the results may be made public". Anyway, when the results came back, we called each company and said, "where do you get your feedstock?" That is when we received a response, "pallets, yes. Drift wood, yes. Melamine or OSB, yes." Just because a log looks "denser", that does not assure you of their ingredients.
Interesting isn't it...EPA regulates the fuel that goes into cars, but there are ZERO EPA regulations pertaining to manufactured solid fuels.
Hmmm I was just down at my stove dealer and asked about Bio Bricks. He said to not use them in a Cat Stove. Said it would burn out the cat and void the warranty
BKVP
Minister of Fire
kennyp2339
Minister of Fire
BKVP
Minister of Fire
I can state for the record, our thermostat can control the burn rate. We can only suggest that not all manufactured fuels are the same. Some have byproducts or other contaminates that can harm ANY stove. One log we had tested was very high in salt content. The feedstock "may include logs scavenged in the form of drift wood". So buyer beware of what you feed your stove.
For the true BioBrick brand, we had them tested as 100% organic material. We do recommend you use approved, tested, manufactured fuels in combination with cordwood. This is because emissions studies done by ADEC in Alaska show the combination of the two results in the cleanest emissions. We also advocate for responsible burning and burning in combination gets there!
Also, limit the amount of manufactured fuels that you burn in any given load. While the thermostat on our stoves can meter out the energy of a given load, it cannot address shortcomings such as failure to close and secure front loading door, closing and locking down the bypass etc.
In my King, I never put in more than four (4) of the NIELS (North Idaho Energy Logs). Each log is 8lbs (+/_ .25lbs) so that is 60k+ Btu's per log. 60 x 4 = 240,000 Btu's in a load. You can see why in a stove that has a minimum air setting and is susceptible to over drafting, this could be hazardous to a stove (also a combustor). So stove manufacturers do have a reason for their recommendations and policies.
Lastly, with so much energy in a single load it is easy to get a fuel rich situation in the firebox if you cut back on the air supply. Just like in a car that backfires through the carb (now you know I'm old car guy!..carb?) Your stove back burp or backfire too. I'm certain that is why the studies done with the blend of cordwood and the NEILS performed best. It allowed for the most energy input but maintained enough M.C. in the load to avoid that "too rich" environment.
BKVP
I looked in the installation manual and there is a warranty exclusion for using compressed pre-manufactured logs. I am assuming that he had to say that to cover his butt. Basically the warranty exclusion is for burning anything except seasoned cordwood. Interestingly the exclusion includes Kiln-Dried wood too.
BKVP
Minister of Fire
You see that is the issue with emission testing to EPA requirements (methods). Forgive the simplicity of this statement:
If you have a hole in the bottom of the stove and you have a metal moving plate that can cover that hole to restrict air intake, you can control the burn rate. Prior to 1984, that movable metal plate was able to cover the entire opening and "simmer". The problem is the simmer mode produces excessive particulates and also creosote formation in the stack. 1984 is when OR began requiring testing and set a maximum standard for emissions. In 1988 EPA adopted the method, change the name from OM7 (Oregon Method 7) to Method 28.
They also lowered the allowable emissions in the 1988 rule making with another reduction in 1990. That number was lowered again in 2015 and again in May of 2020. Each time this is done, the lower burn rate operating temperatures must be increased because in secondary combustion, the lower you burn, the lower the temps and more particulates. When you shut down to "low" now, you must allow enough air into the firebox to maintain at a bare minimum 1176 F to break down and consumer the particulates.
The problem is all stoves are tested on dilution tunnels and that is why you see so much discussion about in-flue dampers on this site. Dilution tunnels do not addresses stack effect. When it 40 degrees outside and 70 inside, the 30 degree differential creates some modest stack effect. So the burn rate of a stove on low is "X". Leaving the air control still in the lowest burn rate position, but the outside temperature drops to 0, now baby that is some real stack effect
So you can't cover the hole any further, but the amount of air (in cfm's) being pulled into the firebox increases vastly. Whether is is catalytic or secondary combustion doesn't matter, you are subject to increasing burn rates. (Over firing) The best way to address this is to use a some form of automation that can continually reduce the amount of air permitted to enter the firebox. It protects the stove (and in catalytic models the combustor) and provides control of the heat output and fuel consumption.Now you see why folks add flue dampers.
BKVP
mellow
Resident Stove Connoisseur
I used wood bricks in a couple cat stoves with great success. I used them to fill in the void around the wood for those long overnight burns.
BKVP
Minister of Fire
How many hours of burn time (hours in catalytic range and hours to enough hot coal left for a quick restart) do you get with such load in your insert?
mellow
Resident Stove Connoisseur
Jotel me this
Feeling the Heat
Just be sure theres no additives and you can burn that till your heart is content (or you run out)
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