Australian lopi vs US lopi

[hansvanderdrift]

Hi

I am about to buy a lopi liberty here in Australia. I noticed a difference between Aussie and US makes.

The lopi in Australia has one secondary burn tube, and it seems the US one has three.

Two questions, can anyone in the USA confirm the lopi liberty has 3 tubes? Do you think only one tube would affect the performance of the wood stove?

Thanks

 

[fossil]

My Lopi Liberty has three secondary burn tubes. I'm not smart enough to comment on the why or the what if. Rick

 

[BrotherBart]

The Lopi Australia website parts list for the Liberty shows three reburn tubes in the firebox.

(broken link removed to http://www.lopi.com.au/wood-parts.html)

Are you looking at an older used Liberty?

 

[hansvanderdrift]

Hi,

It's a new model (unless lopi have sent out the older models to Australia)

Here is a scree grab from the user manual in Australia. I have highlighted the relevant section. I have also inspected the liberty at the dealers and it has one tube.

 

[begreen]

That's an odd one. Is the manifold set up for 3 tubes with plugs in the holes for two sets?

 

[hansvanderdrift]

Just took a quick photo of the display model. Only one tube and no connections for any others.

 

[BrotherBart]

The Coriolis effect?

Kidding.

That is a monster reburn tube with monster holes in it.

 

[BrotherBart]

Sure don't understand it but you are definitely right. Even the ad brochure just shows one tube.

 

[hansvanderdrift]

I spoke to the Australian importers and he gave me the reasons.

1. We use Hardwoods in Australia (Iron Bark and Blackbutt) a lot harder than the typical woods used in the US. There are more gases released from softwood than Aussie hardwood. So, only one tube is needed, and he said that the extra tubes in fact cause the reverse desired effect.
2. EPA standards are different in Australia and the one tube is the outcome.

I am interested in what this will mean to burn times and heat output.

Thanks for your help.

 

[begreen]

I vote for number 2. The first statement is speculation and possibly incorrect. Most wood burning fuel in the US east is hardwood like white oak, hickory and locust.

 

[begreen]

OK, I see now that the difference is in the testing method. It's very interesting. In the US and Europe they use softwood to test the stove's emissions. In Australia, they use hardwood. So the importer is probably correct that it has to do with the testing standards. I don't think it's that Australians burn more hardwood, it's that the testing is done with hardwood. My guess is that the EPA testing is based off of the WA state standard which uses doug fir, a softwood. More tubes may be needed to burn off the more rapid bloom of gas as the wood heats up. But I believe that the northeast US has the largest number of stove installations and there they burn mostly hardwood. If so, this means our stoves are not necessarily tuned to what the majority of stoves are burning. There is discussion in the US to change testing to burning cord wood.

From what I can tell, the test fuel in Au uses relatively small eucalyptus logs for test fuel. I find this also interesting. Locally I have gotten free eucalyptus because folks are afraid to burn it due to its high oil content. I have burned a little bit and like it as a fuel. Regardless, Australian emission standards are tough and it is intriguing to see how a locally made Lopi stove has been modified to meet them. Thanks for sharing.

 

[BrotherBart]

Well heck. Now I gotta get me an Aussie Liberty.

 

[TradEddie]

Reading that, I'm tempted to block my front tubes, but I'd have no way to know if it's better or worse...

TE

 

[begreen]

Not sure that would work. The rear, single tube does not look like it matches the US rear tube. It looks larger and with bigger holes.

 

[Auzzie Gumtree]

Just a follow up on this - i have noticed that a lot of Australian Wood heaters have '...burn only hardwood ' on a sticker on the wood heater. This means that it has been tested to Australian Standards and that they only used Hardwood when testing and therefore they can only recommend hardwood to burn in the heater. This doesn't mean that the wood heater will not burn softwoods but it hasn't been tested with softwoods. I have also noticed a number of other 'foreign' wood heaters ie from the USA that have also been modified to suit Australian testing. They have had some of the secondary air tubes re-moved. I think (my opinion only) is that if they had them removed to actually reduce / limit the amount of air introduced into the firebox which could potentially over heat the heater especially with the resins associated with gum trees.

I had to modify one of my wood heaters so it could burn soft woods i had to reduce the minimum amount of primary air as the fire would overheat if it was set on the minimum setting with ultra dry pine.

I have a Country Hearth (USA designed made in China) this has the full compliment (4) of air tubes and doesn't have the Burn Only Hardwood sticker on. This burns very well with dry wood (hard or soft) much better, more heat, less smoke, than my much more expensive Australian wood heater.

Here's the Australian Quadrafire 5700 - Burn Only Hardwood.

 

[Kleenburn]

I modified my Lopi Liberty Freedom Bay, from a 3 air tube to a single rear air tube, and blocked and sealed the 4 remaining holes in the air manifold. I used an ordinary 3/4" galvanized steel pipe, as a replacement for the stainless steel originals. I "guesstimated" the hole size, spacing & number from the picture of the Au Lopi pictured in the earlier blog. I have also removed the bottom firebricks, to allow a deeper ash bed that helps preheat air to the rear air tube and the circulating house air. Measuring with a laser thermometer, at operating temperature, the increase in air temp is about 185F, before the preheated air enters the rear vertical chambers. After an initial 15mn hot burn, the air emanating from the single rear tube is so hot, that visible smoke is eliminated from the chimney. The single rear air tube puts out so much super heated air, that refilling the firebox is an exercise in speed. I burn mostly seasoned hardwood, sometimes mixing soft & hardwood for a hotter fire. An all night full load throttled down fire can output usable heat for over 10hrs, with very little smoke. and plenty of hot coals left over to start again in the mourning. I don't firmly attach the blower assemble to the bottom of the stove, but rather let it rest on the hearth beneath the lower shelf of the stove. There is a visible 1/2" gap between the shelf and blower housing, which looks like a dark shadow line. This air gap helps protect the expensive plastic blower fans from melting, should there be a power failure, before the blower assembly can be pulled back a bit. The sleeve bearings of the blower motors should be oiled about once a month, and cleaned of dust regularly.

 

[heavy hammer]

So which is a better technology.

 

[Kleenburn]

I think the down under Australian Lopi Liberty, with one single rear burner tube, burns cleaner, than the USA 3 burner tube model. The Washington state, EPA burn cycle testing, requires that "crib" wood be used. Crib wood is kiln dried Douglas fir end cuts or other scrap kiln dried soft wood. In order for one to be EPA compliant, you would have to only burn kiln dried soft wood in the USA. By contrast, the Australian EPA testing uses any kind or dry cord wood, and further rates the stove on total emissions for a 100Kilograms of wood per burn cycle. That's 2.5gr/100Kgr vs. 2.6gr/hour burning KDsoft wood. 100Kgr of wood is about 36lbs or, enough to fill the firebox completely full. This amount, depending on wood thickness, might take 4hr to completely burn, depending on the opening draft of the front air dampner. That's 2.5gr's of smoke over 4hrs vs 2.6gr's X 4hrs; over 4x more particulates emitted for the USA 3 air tube model.

 

[Kleenburn]

Just a Short Follow-Up: I'm surprised no one has asked me what size & spacing are the holes in the rear burner tube? Well, I'm still experimenting, but for the Lopi Liberty Freedom Bay 3/4" diameter standard galvanized schedule 40 steel pipe I'm using, after 3 try's I've settled on the following configuration:

20 holes evenly spaced from end to end (about 1" apart). The first 4 holes at each end are 1/8" diameter with a 60degree
chamfer about 1/2 way through the wall thickness; the remaining holes are all drilled 3/16"-no chamfer. The tube is angled
down slightly toward the front door lower edge, about 10 degrees; in other words, not level. Too many hole's, or too large
seems to result in a smoky chimney and incomplete combustion of smoke gas's; the rear air tube becomes black with soot!
There seems to be a "Goldilocks" configuration for the rear air tube and the super heated air/fuel mix. Combined with the throttled
opening of the front air dampner, everything has to be just right for a smokeless chimney. I've learned to tell when things are
burning correctly by the color of the flame; red-orange = incomplete combustion and lots of smoke. A bright yellow flame with
white tips, or a white flame with blueish tips is especially hot and nearly smokeless.

The other original air tube's are discarded and the mounting hole's are plugged and sealed with fabricated scrap metal & furnace cement, forcing the super heated air out of only the rear air tube. Under vigorous burning conditions, with yellow flames & white tips the stove fully heats up in about 20mn and stays hot as long as the burning conditions are maintained. For an all night burn, when the stove is up to full temperature, I load up the box, and throttle the front air control down to about a 3/16" opening, which forces most of the incoming air through the rear air tube. I get a clean burn of more than 12hrs; half way through the long burn cycle the flames are bluish-white, and the logs & charcoal are glowing cherry red. With a decent ash bed I've had warm/hot coals last more than 16hrs. You must use well seasoned hardwood for best performance!

 

[mellow]

Very interesting findings, maybe that is why some of these hybrid stoves can get away with only 1 burn tube.

 

[Cootapatamba]

Just took a quick photo of the display model. Only one tube and no connections for any others.

Hello Hans,
Just found this site and your post, I was also curious about the tubes which led me to the blog.
Have you purchased one yet?
If so I'm sure that you are quite satisfied with its efficiency.
Hope to hear from you about it.

 

[Cootapatamba]

Here's the single gas tube working like it had LPG going through it... sorry about the reflections

 

[Cootapatamba]

From what I can tell, the test fuel in Au uses relatively small eucalyptus logs for test fuel. I find this also interesting. Locally I have gotten free eucalyptus because folks are afraid to burn it due to its high oil content. I have burned a little bit and like it as a fuel. Regardless, Australian emission standards are tough and it is intriguing to see how a locally made Lopi stove has been modified to meet them.

Free fire wood is a bonus, especially eucalypt hardwoods, you shouldn't be afraid of the oil content because that's in the leaves. Dry leaves are handy for getting a fire going, although a bit smokey.

 

[begreen]

Yes, I have a big euc on the property and it needs limbing every 5 years or so. I burn the wood but gave up trying to split it. It just mushes, even with a power splitter. So I stack the rounds and let them dry for a couple years. Burns fine.

 

[EatenByLimestone]

The stainless baffle on the pe stoves has relatively few holes of large diameter.