Osburn 3500 Wood Insert Important: the Osburn 3500 Wood Insert must be installed in a masonry fireplace with a listed liner. Osburn strictly forbids installing it in a factory-built (zero clearance) fireplace. The Osburn 3500 Wood Insert combines power, efficiency and safety. At 110,000 BTU/h from a 3.5 cubic foot firebox it is the largest insert Osburn builds, rated for 1,000 to 2,700 square feet with a 10-hour maximum burn time, and its sober lines give way to one of the largest glass surfaces in its category. Its flawless design reveals all the Canadian know-how in terms of alternative heating and will quickly become the house favorite. No harsh winter can resist it!Because each house is unique, choose the door overlay, the faceplate and the trims that suit you! Will It Fit? Measure your existing masonry fireplace opening before ordering. The 3500 Wood Insert needs at least: Minimum fireplace opening height 26 1/4" Minimum fireplace opening width 31" Minimum fireplace opening depth 18 3/8" Fireplace type Masonry only — factory-built fireplaces are not permitted Chimney liner 6" listed liner required, minimum 12' height Note that this insert is 29" deep overall against an 18 3/8" minimum opening depth, so a good part of the body sits forward of the hearth — check your mantel and surround clearances as well as the opening. Performance Maximum heat output (dry cordwood) 110,000 BTU/h (32.2 kW) Overall heat output range 17,200 – 57,800 BTU/h (5.0 – 16.9 kW) Recommended heating area 1,000 – 2,700 sq ft (93 – 251 m²) Average overall efficiency (HHV) 71% Average overall efficiency (LHV) 76% Optimum overall efficiency 77% Average particulate emissions 1.6 g/h (EPA / CSA B415.1-10) Average carbon monoxide 73 g/h Maximum burn time 10 hours Overall firebox volume 3.5 cu ft (0.099 m³) EPA loading volume 2.88 cu ft (0.082 m³) Recommended log length 16" (406 mm), loaded east-west Blower Included, up to 144 CFM Specifications Combustion technology Non-catalytic High-efficiency certified appliance Yes, EPA 2020 approved Fuel type Dry cordwood Maximum log length 22" Log positioning Loading over width and over depth Chimney diameter 6" Flue outlet diameter 6" Type of chimney Liner - ULC-S635, CAN/ULC-S640, UL1777 Minimum liner height (feet) 12' Baffle type C-Cast or equivalent Approved for an alcove installation Not applicable Approved for a mobile home installation No Fireplace type Masonry only Shipping Weight 540 lb (245 kg) Door type Single, glass with cast iron frame Glass type Ceramic glass Glass surface – dimensions (Width X Height) 18 7/8" X 11 3/4" Glass air-wash system Yes Premium quality blower included (CFM) 144 Overall dimension (Height) 24 7/8" Overall dimension (Width) 30 3/8" Overall dimension (Depth) 29" Door opening – dimension (Height) 9 7/8" Door opening - dimension (Width) 19" Firebox – dimension (Height) 12 7/8" Firebox – dimension (Width) 22 7/8" Firebox – dimension (Depth) 20 1/8" Fireplace opening – minimum (Height) 26 1/4" Fireplace opening – minimum (Width) 31" Fireplace opening – minimum (Depth) 18 3/8" Firebox lined with refractory bricks for better heat distribution Yes Stainless-steel secondary-air system improving gas combustion Yes Steel thickness – body 3/16" Steel thickness – top 5/16" USA standard (emissions) EPA Canadian Standard (emissions) CSA B415.1-10 USA standard (safety) UL 1482, UL 737 Canadian standard (safety) ULC S628 Tested and listed as per applicable standards By an accredited laboratory (CAN/USA) Warranty Limited lifetime Manuals/Documents Installation and Operation Manual Dimension Sheet
