Vented 24″ Millivolt Control Slope Glaze Burner – NG This burner is certified for use in an existing fireplace with an open damper flue. Vented systems do not burn the gas used cleanly and therefore need to be exhausted through an open chimney – similar to burning wood. A vented burner can only be used in this application. It is not convertible to vent-free operation. A vented burner can be rated up to 75,000 BTUs to create taller flames but is still only rated as a decorative system and is not for use as a heat source and cannot be operated by a thermostat. A vented burner is only available in a manual model and a millivolt model. This is a manual model. The BTU input range is from 40000 (reduced*) – 65000. The main advantage of a vented burner is the more realistic yellow flame created by the open flue. Unfortunately, to get the more realistic fire-look, the heat goes up the chimney as well. If you are only looking for a decorative, non-heat source with more realistic fire then a Vented Burner is what you want in a gas log set. Includes: Slope Glaze Burner, Embers, Lava Rock, Flex Line and Fittings. Features: Fuel Type: Natural Gas. Ignition Type: Millivolt Control. Type of Venting: Vented. Fireplace Style Single Sided. This log set is to be installed only in a solid-fuel burning fireplace with a working flue constructed of non-combustible material. The vent damper must also have a damper clamp attached to it to keep the damper from accidentally closing during operation. Certified for installation as vented log set ONLY. The installer must block the fireplace damper partially open. A special flue-damper clamp is included with burner. Specifications: Overall Dimensions: 24″ (L). Minimum Dimensions for Fireplaces: 30″ (Front Width) x 15″ (Depth) x 22″ (Height). BTU: 50000* / 75000. Required: Must Choose Log Set to Complete This Unit. (Not Included, Sold Separately): Sassafras 24 inch Refractory 6-piece Log Set (LS24RS). Stacked 24 inch Aged Oak Refractory 8-piece Log Set (LS24SRAO). Sassafras 24 inch Refractory Super Size 7-piece Log Set (LS24RSS). Refractory 24 inch 13-piece Log Set (LS24P). Birch 24 inch Ceramic Fiber 4-piece Log Set (LS24B2). Charred Oak 24 inch Ceramic Fiber 4-piece Log Set (LS24C2). Charred Oak 24 inch Super Size Ceramic Fiber 6-piece Log Set (LS24C2S). Logs are shown in image, however not included in this product.