Portage & Main

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Who Has the Best Outdoor Wood Boiler ?

Want to live a more self-sufficient, heating-independent life style?

Not sure if you will be able to keep ahead on the seasoned wood that is required for a downdraft wood gasifier?

Well, here’s some great news for you.

The Portage & Main Ultimizer is designed to give the highest efficiency and longest life expectancy of any updraft hydronic heater. It burns so cleanly that it is considered to be a “hybrid updraft gasifier” and much more efficient than the traditional conventional boilers of our competitors.

We learned a lot during the development of the Ultimizer, including how to burn smoke by incorporating a “hot burn zone” in a “dry based” design.

This means that almost any type of wood can be burned more efficiently. Even wood with a higher moisture content than usually recommended for an outdoor boiler.

The traditional boilers of our competitors are still a firebox (or drum) that is surrounded by a water jacket. The Portage & Main is different by design.

Imagine a traditional wood stove in a house, heating air inside a room.

The wood stove does not have a water jacket. This allows the stove to burn at very high temperatures because it doesn’t have water absorbing and dissipating the heat from the fire.

Picture the dancing flames behind the glass. Those flames are essentially the wood gases burning off due to gasification. For gasification to occur, high temperatures have to be maintained.


So, coming back to our competitor’s boiler with a firebox surrounded by water and no refractory brick. Gasification is not possible in that boiler. This means that wood gasses (and heat) exit through the chimney as unburnt black smoke.


The Portage & Main is different by design. Here’s why.

The Ultimizer is a “dry base” design. I.e. there isn’t a water jacket at the bottom of the fire with the water taking the heat away from the fire before complete combustion is able to occur. There is a 2-1/2” thick durable refractory brick surrounding the base of the fire and 12” to 16” up the sides (depending on the model). Not only does this provide more heat to enhance complete combustion but means that ash does not have to be raked and stirred to prevent ash line corrosion

(as with our competitors 409 stainless steel model), This refractory absorbs and stores heat at much higher temperatures than water alone could store it at. All that HEAT is then available to meet one of the 3 requirements of the fire triangle, and allows the burning off of wood gasses.

There is an additional, full length multi-pass, heat exchanger at the top of the Ultimizer. This was perfected by Portage & Main more than 50 years ago. Water completely surrounds this heat exchanger too, and allows the efficient transfer of even more heat into the water.

Only then is the heat circulated to the building that requires heat.

It’s worth noting that our competitors have now taken on the multi-pass heat exchanger idea too. However, their heat exchangers are short – not a full-length design. So again, they lose out on the chance to extract as much heat as possible – a less efficient design which will cost the end user time and money.



So, to summarize

1. Higher temperatures in the fire box (due to the refractory brick) means less smoke (ie. wasted energy).

2. Unlike other brands, due to the high temperatures in the firebox, we don’t need to introduce a larger amount of air, with an oversized fan, to try and compensate for a lower combustion temperature. The Ultimizer is 30% more efficient than non-hybrid models that have unbalanced fuel/oxygen/ heat ratios which result in wasted heat exiting the chimney

3. The Ultimizer is a sectional, long life boiler, not a throw away like other manufacturer’s designs. At the end of its long life the water jacket can be replaced. Just remove the top half of the boiler and bolt on a new jacket – and your good to go again. This means a very sustainable warranty, resulting in the savings of several thousand dollars by being able to rebuild rather than replacing the entire boiler.

4. Due to the gasification that occurs at the bottom of the firebox customers will definitely burn less wood over the year compared to a conventional regular competitor designed boiler.

5. Portage & Main Ultimizers are the heavy weights in the outdoor boiler industry. Our boiler weighs 1000 lbs more than a size comparable competitor boiler. The extra weight equates to durability and performance due to all that refractory.

6. Unlike our competitors with their 409 stainless steel wet base designs, the Ultimizer does not require the daily raking and stirring of the ashes in order to prevent ash line corrosion.

7. Whether your wood is perfectly seasoned, or not quite fully seasoned, the Ultimizer is definitely up to the challenge. You will still have the best possible efficiency due to the drying effect that the hot refractory has on the fuel.

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About Portage & Main

Our head office is located in Prince Albert, Saskatchewan, Canada. Our dealer network spans North America and we would be glad to put you in touch with one of our knowledgeable agents. Our staff oversees the development of new products, monitors production, designs heating systems, and offers tech support for installers. All our wood furnaces are designed for installation outdoors and deliver wood heat indoors.






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