Custom Explosion-proof Duct Heaters
Wider range of sizes than available in the other two designs, Vertical airflow, Ratings up to 750 KW, 600 volts.
Heaters are generally constructed per Series EP2, except that element terminals as well as control components are built into a single cast aluminum explosion-proof enclosure.
Construction
Frame
Sized to fit the duct. Standard flanged design recommended to support heater weight. Slip-in also available, if necessary, to match other equipment. Galvanized steel standard; stainless steel optional.
Control Enclosure
NEMA 7, 9 cast aluminum box with hinged cover houses controls and element terminals. Weatherproof construction optional.
Heating Elements
Heavy wall, large diameter stainless steel finned tubular elements, individually removable for servicing.
SCR Temperature Control
SCR’s with zero-cross firing provide precise proportional control. SCR’s also minimize element operating temperatures for extra safety. Optional on/off single or multi-stage control also available.
Control Transformer
Furnished as standard with fusing as required.
Overtemperature Protection
Thermocouple controllers measure element sheath temperature.
- Automatic reset control resets when temperature drops to a safe level.
- Manual reset control, with external button, provides back-up protection.
Fuses
Individual circuit fusing for heaters drawing over 48 amps to meet NEC requirements.
Airflow Interlock
Fan relay prevents heater operation, unless fan is energized. Optional builtin or remote explosion-proof airflow switch can be provided.
Magnetic Contactors
Furnished as required for temperature and safety controls.
Classifications
- Class I, Division 1 and 2 Groups C and D
- Class II, Divisions 1 and 2 Groups E, F, and G
