Base heater includes: U.L. label or Applied Researchlabel, heating elements, primary disc type automaticreset hi-limit, secondary hi-limit of fusible links,magnetic contactors for each step, fan relay or airpressure switch, circuit fusing on heaters exceeding
48 amps, field terminal connections for power source,low voltage source and fan interlock source, enclosedpanel, element wrapper, grounding terminal, wiringdiagram and all aluminized steel panel and frame.
Non-labeled heaters may have the fan relay; airpressure switch and/or circuit fusing installed remotefrom the heater.

Finned Tubular Type

18 gauge minimum, aluminized steel throughout.
Non-ventilated, hinged cover control box.
Limit controls replaceable without removing heaterfrom duct.
Air flow positive or negative pressure.
Elements are manufactured with high quality alloyresistance wire-centered and permanently encasedwithin highly compacted, rock-hard refractorymaterial, surrounded by a steel sheath. Helical finsare furnace brazed to the sheath for rapid heattransfer. Sheath and fins are coated with a hightemperature fired CERAMIC for corrosionresistance. All element terminations are stainless steel.