Finned Tubular HVAC Duct Heater

Our product offering ranges from standard tubular heating elements to the most sophisticated, custom designed systems. Our attention to detail and rigorous testing give worldwide customers premium products that they receive quickly and at a fair price.

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Standard Features

Duct heaters shall be Heatrex
Type TFHU Standard Slip-in heaters.

Heaters and panelboards (if required) shall meet the requirements of the National Electrical Code and shall be listed by Underwriters Laboratories for zero clearance to combustible surfaces and for use with heat pumps and air conditioning equipment.

Heating elements shall consist of a coil, 80% nickel, 20% chromium, Grade A resistance wire, precisely centered in a stainless steel tube filled with granular magnesium oxide. A stainless steel fin is to be helically wound onto the tube. Elements are to be furnished with mounting flanges, making them individually removable through the terminal box.

Heater frames and terminal boxes shall be corrosion resistant steel. Unless otherwise indicated, the terminal box shall be NEMA 1 construction and shall be provided with a hinged, latching cover and multiple concentric knockouts for field wiring.

All heaters shall be furnished with triple over temperature protection. A disc type and linear, automatic reset thermal cutout are included for primary over temperature protection. All heaters must also be furnished with a linear type manual reset thermal cutout with backup contactors (as required). For secondary over temperature protection, heat limiters or other fusible over temperature devices are not acceptable.

Heaters shall be rated for the voltage, phase and number of heating stages indicated in the schedule. All three-phase heaters shall have equal, balanced, three-phase stages. All internal wiring shall be stranded copper with 105°C insulation and shall be terminated in crimped connectors or box lugs.

Terminal blocks shall be provided for all field wiring and shall be sized for installation of 75°C copper wire rated in accordance with NEC requirements.

Heaters shall be furnished either with the Control Option specified in the schedule and described below or with the specific components listed in the schedule.

Product Option

Non UL listed
UL listed

TFHU (standard slip-in)

Control Options
Control G (contactor control)
Control J (pneumatic control)

Control K (SCR control)

Custom Options
Disconnecting Contactors (substitute for De-Energizing Contactors)
Dust-tight Terminal Box
Fan Relay (in addition to Airflow Switch)
Fan Relay (substitute for Airflow Switch)
Insulated Terminal Box
Mercury Contactors (substitute for De-Energizing Contactors, not available in all areas)
Pilot Lights “Heater On”
Pilot Lights “Low Airflow”
Pilot Lights “Stage On”
Remote Panelboard
Step Controller

Closed Tank Heating

Watt Density

Percentage of Wattage

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