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Indoor Multi-Fuel Boilers Products

Ten Year Warranty

The WOC40 model is the smallest Multi-Fuel boiler we offer, able to heat homes ranging from 1,000 – 4000sqft. They are perfect for homeowners looking for a rugged, durable boiler with the ability to burn a variety of fuels. For more sizes… Click here

The WOC40 is a simple, traditional, hand-fired, updraft boiler. They are made out of ¼ inch steel plate…

…which enables it to give comfortable heat to your family for a lifetime or even two. Having been manufactured for over 30 years you will have peace of mind in knowing that you will be able to keep your family warm and save a lot of money for years to come.

Our trademark caste iron grate and our Dual Draft systems make it possible to burn various types of solid fuels (hard coal and soft coal) in the same combustion chamber and gives the ability to customize the airflow to maximize burn efficiency with each kind of fuel. It can also be configured to operate without electricity.

The difference between our WC and WOC models is a special burn chamber on the rear of the boiler that allows a burner to be fitted on it. We use a separate burn chamber so that you are able to create a good flame pattern, which allows the burner to operate efficiently, and the separate burn chamber protects the burner’s nozzle when burning the various other fuels. The burner fires into the separate burn chamber which leads into the main firebox and so whether you are burning oil or hard coal or soft coal you only need one flue. A liquid fuel backup burner (oil) is included. It comes standard with a Riello #2 fuel oil burner that is controlled by the boiler’s aquastat, as well.

An Automatic Switchover feature, from coal to oil if the water temperature drops due to lack of fire, is an available upgrade on all WOC models. The Automatic Switchover option gives you the flexibility and freedom in knowing that your home will not go cold if you, for example, decide to go away for the weekend.

The WOC40 comes standard with:

  • Oil Burner with Manual Switch-Over
  • Legacy Grate System
  • Large 14” Loading Door
  • Automatic Dual Draft System – Forced Draft Blower and Natural Draft Damper
  • Firebrick Lined Firebox
  • Water Cooled Baffle (for increased efficiency)
  • Hydro Tested to 60PSI
  • Constructed of ¼” Steel Plate
  • Honeywell Circulator Control Aquastat
  • Temperature/Pressure Gauge
  • ASME Tested Pressure Relief Valve
  • Load Door Smoke Flap

Our Multi-Fuel boilers’ cost of ownership is one of the lowest in the industry! $40.00 – $50.00 per year on average!!

Traditionally, Multi-Fuel boilers have been sold as wood/coal combinations, however, due to EPA Phase 2 regulations, these units are no longer sold for continuous use with wood.

To view our Multi-Fuel boilers that do not have an oil burner option. click here WC40

For automatic feeding boilers please explore our Wood Gun or Coal Gun product lines

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  • Flexible Fuel Options
  • Oil/Propane/Natural Gas Backup
  • Easy Maintenance
  • Cost Effective
  • Fuel Efficient
  • Lifetime Durability

Call (717) 987-0099 for pricing

Assembled Specifications

BTU/hr Coal


BTU/hr Oil or Gas


Typical Heating Capacity (square ft)

1,000 - 4,000

Standard Door Opening


Firebox Capacity (cubic ft)


Firebox Length (in)


Water Capacity (gal)


Width (in)


Height (in)


Height to Flue Opening (Center) (in)


Depth (in)


Weight (lbs)


Flue Size (in)


Coal Capacity (lbs)


Propane/Natural Gas Backup

Fuel oil backup is standard for WOC models but propane or natural gas back up options are available for an additional cost.

Automatic/Manual Switching

For #2 fuel oil, the backup system can function in an automatic switch-over scenario, with fuel oil taking over when the boiler has exhausted its coal fuel. For other fuels, such as natural gas or propane, switch-over is manual only.


Domestic Coil

This Domestic Coil features a 100° F rise at 5 gallons per minute, 50° water inlet temperature and 65 PSI water pressure. It is threaded into a 4 IN NPT threaded fitting provided on the boiler for this purpose

Insulation Jacket

Our base unit Multi-Fuel boilers have no insulation on the outside of the boiler, allowing maximum heat radiation in the boiler room. If you prefer to circulate more of this heat, an insulation jacket can be added to the boiler. This insulation jacket is comparable to that used on the Wood Gun or Coal Gun boilers

ASME Certification

The ASME Certification guarantees the steel grade and weld quality of the boiler water jacket. Each ASME Certified water jacket has been pressure tested to 60 PSI, and includes a 30 PSI release valve.

Low Water Cutoff

A Low Water Cutoff senses the water level in the boiler’s vessel and will shut the unit down if the water level drops to an unsafe level. Available with automatic reset or manual reset.