233 Series Explosion-Proof Unit Heater
Heatrex’s 233 Series Exp explosion-proof unit heater is designed with both safety and versatility in mind.
Standard Features
Industry’s Lowest Ignition Temperature Code Rating
T3C, 320°F (160°C)
Dual Over temperature Protection
With both automatic and manual reset over temperature cutouts for additional safety.
Nontoxic Propylene Glycol Heat Transfer Fluid
Low 70 PSIG Relief Valve Setting
This assures that in an emergency, the initial escaping vapor temperature remains below the 320°F (160°C) ignition temperature.
Corrosive Resistant Options
Heatrex offers three constructions suitable for most applications. Standard construction for use in dry non-corrosive areas includes : Welded steel heat exchanger; powder-coated cabinet; epoxy-coated motor. A 316 stainless steel construction suitable for Waste Water Treatment Plants includes : 316 stainless steel heat exchanger, headers and tubes with aluminum fins; stainless steel cabinet; corrosive resistance hardware; epoxy-coated motor. Third construction is suitable for use in Chemical Plants where chlorides are present and includes : Heresite® coated heat exchanger, cabinet, fan blade; corrosive resistance hardware; epoxy-coated motor.
Construction Features
Heat Exchanger
Efficient liquid-to-air design utilizes an all welded steel headers and finned tube construction with spiral wound aluminum fins. Industrial grade Heatrex heating elements are immersed in a nontoxic, inhibited, propylene glycol heat transfer fluid that provides freeze protection down to -49°F (-45°C). The heat exchanger is hydrostatically tested at 350 psig. A pressure relief valve provides excess pressure protection and is set at 70 psig.
Fan Motor Assembly
Consists of an explosion-proof motor fitted with an aluminum fan blade. The motor has double-shielded, permanently lubricated ball bearings and automatic reset line breaking thermal overload protection. Motors furnished on standard units operate at line voltage and are prewired to the control enclosure so separate field wiring to the motor is not required. The standard motor is rated for Class I, Groups C and D, Class II, Groups F and G. The minimum operating temperature is -14°F (-25°C) and the minimum storage temperature is -49°F (-45°C).
Cabinet/Louvers
Industrial grade, corrosion resistant construction fabricated from powder coated 14-gauge galvanized steel. The adjustable louvers have minimum opening safety stops.
Controls
Factory mounted on the unit heater. Standard built-in controls include automatic and manual reset over temperature cutouts, controlling magnetic contactor, 24-volt control circuit transformer and incoming power terminal blocks housed in a NEMA 7, 9 cast aluminum enclosure.
Applications
Aircraft Hangars/Service Areas
Chemical Storage/Handling Areas
Coal Preparation Plants
Compressor Stations
Grain Elevators
Oil Refineries and Rigs
Paint Storage Areas
Petrochemical Plants
Sewage Pump Stations/Treatment Plants
Spray Booths
Standards
Class I, Divisions 1 and 2, Groups C and D
Class II, Divisions 1 and 2, Groups E, F and G
Class I, Zones 1 and 2, Group IIB
Temperature Code T3C, 320°F (160°C)
