LDH SERIES and D SERIES Duct Heaters

Easily Adapted to Many Non-Pressurized Air Heating Systems

Watlow duct heaters are constructed of sturdy 0.430 in. (11 mm) diameter WATROD heating elements mounted to a 1⁄4 in. (6 mm) thick steel flange. These air duct heaters are easily adapted to many non-pressurized air-heating systems.

Duct heaters are easily installed in applications requiring a wide range of temperature versus air flow combinations.

The modular duct heater offers increased reliability. The individual modules are removable through the housing of the assembly, which eliminates the need to pull the complete heater from the ductwork. This reduces downtime costs because the heating elements can be replaced individually. Performance improvements include quicker response time and reduced infiltration from the air stream being heated into the electrical enclosure.

Watlow air duct heaters offer advantages over gas or oil fired and open coil electric units with:

-Installation flexibility—no flues or fuel lines
-100 percent energy efficient—no energy loss up the flue
-Universal availability of electricity
-Resistance coil in sheath is protected from corrosive environments
-Duct heaters with general purpose enclosures meet UL® and CSA component recognition to 480 and 600VAC maximum respectively—UL® and CSA file numbers are E52951 and 31388.

features & benefits

Long life alloy 800 sheath resists corrosion/oxidation while protecting resistance coils against contamination

MgO insulation filled elements compacted to rock hard density maximizes dielectric strength, heat transfer and life

Field replaceable heating elements permits easy service and reduces downtime

General purpose terminal enclosure offers easy access to wiring

WATROD hairpins are recompacted after bending to eliminate hot spots and electrical insulation voids


Maximum Operating Temperatures
Maximum Watt Densities
Alloy 800 2050 1120 30 4.6

related documentation

  • User Manuals

    FIREBAR Circulation Heater Installation & Maintenance Manual

  • Catalogs

    Thermal Component Reference Guide

    Heater Catalog (Section) - Agency Certifications

    Heater Catalog (Section) - Air Heaters

    Heater Catalog (Section) - Heater Reference Data

    Heaters Catalog

  • Specification Sheets

    Duct Heaters

    Modular Duct Heater

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quality certificates 1

ISO 9001-2008 Hannibal