ADH-ADHT-HEATER

Supported Applications

The Omega ADH and ADHT series are High Temperature Air Duct Heaters designed for heating air in drying, curing, heat treating, re-heating, and dehumidification applications. These units utilize rugged construction with long-life metal sheath tubular elements to maintain performance under demanding thermal loads.

Operating Conditions & Performance

The series is divided into two temperature classes based on maximum outlet air capabilities:

• ADH Series (Low-Medium Temperature): Provides outlet air temperatures up to 426°C (800°F). These units operate at a watt density of 30 W/in².
• ADHT Series (High Temperature): Reaches outlet air temperatures up to 648°C (1200°F). These units operate at a watt density of 20 W/in² and include standard overtemperature protection via a K-type thermocouple welded to the element sheath surface.

All models in both series are rated for power outputs ranging from 5 kW to 270 kW, operating on 480V, 3-phase supply. The heating elements feature a 0.475" diameter tubular design with high-grade Incoloy sheath material selected for excellent corrosion and oxidation resistance at elevated temperatures.

Configuration Options

The ADH-ADHT series offers configurable options to address specific installation requirements, including:

• Housing Materials: Standard terminal housings are constructed from 18 gage aluminized steel. High temperature units feature stainless steel material for the 3" insulation housing and element support plate.
• Process Connections: Units mount to a heavy ¼ or ⅜" thick steel flange, with mounting gaskets packed separately to minimize leakage.
• Special Service Options:
  • Gas tight design: Achieved using threaded compression fittings with fiber washers to attach heating elements to the flange.
  • Moisture or explosion-resistant terminal housings: Available for applications requiring special terminal protection.
• Electrical Connections: Terminal blocks include individual threaded stud type terminals for each circuit, designed to maintain low wiring compartment temperatures and provide easy access for field wiring.

The series supports mounting in any position—top, side, or bottom entry (preferred)—with minimum duct size requirements defined as dimension A or L plus ¾" and dimension B plus 1⅝". Maximum work temperature is dependent on air velocity.

Key Product Differences

The primary distinction between the two series lies in their maximum operating temperatures, watt density ratings, and standard safety features:

• ADH Models (e.g., ADH-035/480V/3P): Designed for applications up to 800°F. These models utilize a higher watt density of 30 W/in² and do not include the standard overtemperature thermocouple found on high-temperature units.
• ADHT Models (e.g., ADHT-020/480V/3P): Designed for applications up to 1200°F. These models utilize a lower watt density of 20 W/in² and come standard with a K-type overtemp thermocouple wired to a terminal block.

Model numbers follow the format ADH--480V/3P or ADHT--480V/3P, where the kW value indicates power rating. Higher wattage models (e.g., 216F, 270F) utilize different dimensional configurations to accommodate increased element counts and circuit arrangements.