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[ijon]

What are your thoughts on Woodmaster's clean fire boiler. It looks like pretty  good design.

[mlappin]

Honestly?

The catalyst and pressurized design are a step backwards to me.

[slimjim]

I'm not exited about the catalyst but I do like the idea of an external pressurized tank and their claims on emissions / stack temps are very good. I'll say this for them, they do tend to think out of the box, sometimes that's a big hit and sometimes it's not. I guess it all depends on warranty, price and dependability.

[mlappin]

I have to respectably disagree, a pressurized tank just adds another level of complexity that doesn’t have to be.

[slimjim]

I as well get nervous regarding pressurized tanks in an outdoor wood boiler, however it does add to the lifespan of the unit and if properly installed and maintained, it can be very safe.

[hondaracer2oo4]

I watched the 18 minute video on their website. Looks actually very interesting, I would like to hear about some real users with them. I thought at first 'why would they go with a cat and not a downdraft gassification?" The answer became obvious though when I realized what they were doing, a dry firebox with a modulating output. Actually seems pretty innovative, is anyone else building anything like this?

[mlappin]

Your G series uses a modulating damper to control the combustion process.

Not a huge fan of a dry firebox, have welded many a crack shut in forced air wood furnaces, however given that it is an outdoor boiler as long as the crack wasn’t in a critical location it could most likely be ignored.

[hondaracer2oo4]

The g series is very crude in its 'modulating'. The clean fire uses the delta t from the supply to return lines to modulate the btu output to match the demand.

[Pointblank]

Looks like they've taken the owb design to a whole new level. Innovative for sure.  I like the dry firebox and a 30 year lifespan would be awesome.
Im curious how the modulating fire works on warmer days. Would prolonged idling adversely effect the catalyst?

[MattyNH]

Very interesting! I checked out the web sight and 2 videos. Curious how much wood it will save if any compared to the Heatmaster and Edge..I got a WM dealer not too far from me..Maybe ill check them out..
 

[mlappin]

The g series is very crude in its 'modulating'. The clean fire uses the delta t from the supply to return lines to modulate the btu output to match the demand.

Just not sold on mild steel anymore. I’ve spent a rather decent portion of my life welding patches in stuff that rotted out, sumps, auger hoppers, grain boxes on trucks, gravity wagons, wood burning stoves, etc. Anymore if it’s something we plan on keeping and its feasible most of my patches are of stainless steel anymore. I’ve even made new grates for the floor drains in our basement out of stainless, the old ones were cast and were made so the bottom part of the casting formed the water trap, a chunk of ten gauge stainless and 3” stainless pipe welded to the bottom made a grate I’ll never have to replace.

[hondaracer2oo4]

I agree on the mild steel. But pressurizing it should take care of that issue I think. According to the numbers the g200 will actually run as clean and actually has a better efficiency rating. That being said those numbers are at steady burn rates for the g200. If the g200 was charging up storage and running and a consistent  rate, that would work but idling time hurts those efficiency numbers. That's why the constant running/modulating design of the clean fire is interesting.

[boilerman]

Modulating combustion by controlling air flow is good feature. Central Boiler has been doing that in their Eclassics and Edge models for years. Using a thermocouple in combustion area that monitors combustion temps and modulates the amount of air injected into that area throughout burn cycles. Heatmaster units do not do that, there is no sensor in the unit that monitors combustion, just injects air on a preset timing sequence like the old Eclassic 2300 did. The Cleanfire is quite small though, only 102,400 max btu output, small 28"x30" firebox and small loading door of 16.5"x19"door. I have concerns/doubt about longevity of a cat converter and ability to keep it clean and breathing. Time will tell.

[mlappin]

I agree on the mild steel. But pressurizing it should take care of that issue I think. According to the numbers the g200 will actually run as clean and actually has a better efficiency rating. That being said those numbers are at steady burn rates for the g200. If the g200 was charging up storage and running and a consistent  rate, that would work but idling time hurts those efficiency numbers. That's why the constant running/modulating design of the clean fire is interesting.

But there is still a rather large part of the stove that is mild steel that is not pressurized and subject to condensation. My old stove has never leaked a drop of water, still doesn’t leak, however the door flange and exhaust exit have rotted away from plain old condensation.

Now if they had built it out of 409 stainless then it would not have to be pressurized and still get a long life out of it. There’s a Heatmor down the road thats on its third owner, guy replaced all the external tin on it as it had pin holes rusted thru. The unit itself is still solid with no leaks.

[RSI]

The price of them is very close to the G200. I looked at one at a fair this summer and talked to the dealer for a while. He hadn't run one yet but was pretty knowledgeable about them. I asked him about the dry firebox burning out and he said it wasn't a problem because the water jacket was right behind it so it limited how hot it could get.