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Hyprotherm FLRH-350 Outdoor Wood Boiler

Hyprotherm FLRH-350 Outdoor Wood Boiler


The Extended Winter Sale With Hyprotherm

Due to the success of the recent holiday sale, the owner of Hyprotherm has decided to continue the sale to now receive $300 OFF of any FLRH model from the 85 all the way to the 400 until March 31, 2019! A FLRH model is a front-loading residential wood or coal boiler.

The Hyprotherm, Front Loading, Hydronic series is a front loading furnace with more water capacity and a larger firebox then any other furnace in its class. These wood furnaces feature fireboxes that are 3/8” thick. The water jacket bottom is also 3/8” thick with the sides and top being 3/16”. All of these front loading furnaces come with large 24” x 24” fuel fill doors and removable ash pans to make ash removal simple. They have a flat cast grate and each furnace is pre wired with only one connection to a power supply necessary, making them basically plug and play. Each comes with; lock down vault assembly door latch, two 1” supply and two 1” return nipples. Also includes a water level sight gauge and a digital thermostat to control the combustion blower.

These models are for commercial use only and can be fitted with a shaker grate system upgrade for $864.00


  • Water Capacity; 350 gallon
  • Water Jacket Thickness Bottom; 3/8”
  • Water Jacket Thickness Sides and Top; 3/16”
  • Firebox Capacity; 41 cubic feet
  • Firebox Dimensions; 3/8” thick @ 69.5”L x 30”W x 34”H
  • Overall Dimensions: 108” x 46” x 87”
  • Shipping Weight: 3,580 lbs
  • Fuel Door; 24” x 24”
  • Grate System; Flat Cast (Shaker Grate Upgrade Optional)
  • Ash Cleanout: Removable Ash Pan
  • BTUs; 392,175 @ 180 degree
  • Heatable Area; 9,800 sq ft Approx

The standard insulation on our furnaces is:

2″ of Morgan Super Wool with an R value of 56.8 on the tops and fronts and 3″ of Knauf ET Blanket + 1/4″ of Solar Guard for a combined R value of 23.1 on the rest of the furnace

The cold weather package is R-88.23 on tops and fronts and 68.4 on the rest of the furnace and is available for an additional $307.00

You can find out more insulation information including video demonstrations by going to the insulation page.

Hydronic Installation Manual