OUTDOOR RATED DUCT HEATERS HFO Series / CHMSO Series CHMSO Series The HFO & CHMSO outdoor-rated duct heaters are designed and constructed for fully-exposed outdoor applications. * ETL listed * NEMA 4 and 4X control enclosures * Built with corrosion resistant materials * Available in open coil (HFO Series) & finned tube (CHMSO Series) * In-built disconnect switch * Ideal installations include: rooftop air handling, high humidity areas such as pharmaceutical, food processing plants, beverage production or indoor swimming pools HFO Series FAN FORCED WALL HEATERS 3310 Series (3-Phase Models) * Rounded 20-gauge steel grille * Heater has been designed with a manual reset limit for safe operation * Vane axial fan and steel block fin element * Single pole in-built thermostat with a temperature range of 0° to 110°F * 14 1⁄8 " Wide x 19 ½ " High x 4 " Deep * Voltage options: 208V, 240V & 480V * Can be surface mounted or recessed * ETL listed for the US and Canada