Heatmaster G series Outdoor Boilers

RSI Boilers - HeatMaster SS Authorized Dealer

Outdoor Wood Boilers
Parts and Accessories
HeatMaster SS Website
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HeatMaster G400

G400 Starting at $12,995.00See options
Financing is available upon request

One of the largest gasification furnaces available, the capacity of this unit makes it suitable for many large load applications. It’s capable of heating up to 4 applications at the same time, a home and large shop or a commercial sized shop. It may be all you need for multi-building, high demand applications.

(W” x L” x H”)

29 x 40 x 42

Firebox Door
(W” x H”)

20 x 20.5

Water Capacity
(US Gallons)


Approximate BTUs


(W” x L” x H”)

49 x 78 x 88

8 hour burn rate

180,409 BTU/hr



8 hour efficiency
(Lower heating value)


8 hour efficiency
(Higher heating value)


HeatmasterSS is proud of it’s reputation of producing innovative wood heating methods and our G Series wood furnaces are continuing that trend. They operate more efficiently with fewer emissions than other wood furnaces. They can use up to 50% less wood to create the same heat.

How does it do that?

Wood gas is generated in a high temperature reaction (>700° F) between the wood and a limited amount of oxygen. The heat and lack of oxygen “bakes” the wood, causing the gases in the wood to release in the form of carbon monoxide, hydrogen and carbon dioxide.

The wood gas mixture that is created in the firebox then gets forced through the base of the fire along with any ash that would come with it and burned at temperatures around 2000° F in the gasification chamber. This creates a very hot, very clean burn which helps you get the most out of your fuel. After the gas is burned, the heat is transferred to the water jacket using the heat exchange tubes. Normal exit temperatures of the exhaust are 200 – 300 F.
The most notable indicator of effective gasification is the lack of smoke exiting the chimney.
The gasification process creates longer burn times and can reduce wood consumption as much as 50% compared to a standard wood furnace.

What does it mean for you?

  • Less wood cutting
  • Less ash removal
  • Fewer emissions
  • Fewer trips to the furnace
  • Bottom line – more heat for less


Optional Smoke free loading – Stay clean and smoke free when loading your furnace.

EZ Clean Handle:
The Easy Clean handle makes cleaning the heat exchange tubes a breeze. No need to brush tubes or scrape creosote, you can load and clean your furnace in 5 minutes!

UL approved for indoor and outdoor installation with (bypass option required for indoor use)

Optional Sight Glass:
With the sight glass you can check on the fire without opening the door.
Modern Finish

Heatmasterss warranty – We stand behind every furnace we sell with a Lifetime Limited Workmanship and Corrosion Warranty.

Easy access hinged rear door – The insulated rear door is built with a unique hinge design which allows for easy access to the rear of the furnace and quick and easy removal of the door if required without the use of tools or hardware.

Safe easy-to-use dual firebox door latch – Our carefully designed latch catches the door so it doesn’t swing completely open and expose the user to excessive heat.

Heavy duty multi-layer insulation

Optional Built in Recirc pump
(required when connecting only one loop)

Optional Site Glass in lower door

Draft Inducer Fan

Easy read water gauge

Easy access panel:
Quick open large rear cleanout panel

Please Contact us for more info or with any questions
Philip Howard / RSI
109 Commercial St / PO box 341
Arlington, WI 53911

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