Guide Specs
Series SCH, Steam Make-Up Air Heater, Face-and-Bypass Type, Centrifugal, SK-880-88, Nov 1997
Series SCH was formerly known as Series 88. This guide speci will be updated shortly.
The Steam Make-Up Air Heater, Face-And-Bypass Type, Centrifugal, shall be manufactured by Hartzell Fan, Inc. and identified as Series 88. The design shall be classified as a draw-through type, indoor or outdoor (with minor modifications) packaged configuration for horizontal installation. Units shall be a modular assembly consisting of a fan section, an optional filter section, and a heating section. The fan section shall contain one or more electric motor powered, belt driven, centrifugal fans. The filter section shall contain a framework supporting reusable or throwaway type air filters. The heating section shall be a mixing plenum with the plenum inlet divided into two sections: heated and unheated. The heated section shall be equipped with a steam-to-air heat exchanger downstream of a motorized damper. The unheated section shall be equipped with a motorized damper only. A control system to activate/deactivate the unit, modulate the outlet air temperature, and protect the integrity of the coil shall be furnished. Forty models shall be available providing 741,000 to 3,830,000 Btuh of heating capacity (using saturated steam at 5 psig with an entering air temperature at 0° F.) from 8,000 to 45,000 SCFM of airflow, respectively, at 0 to 1.5 in. W.G. external static pressures.
The centrifugal fan(s) shall be a double width, double inlet wheel design with forward curved blades formed of low carbon steel. The fan housings shall be formed of low carbon steel and continuously welded. The fan wheels shall be mechanically attached to and supported by ground steel shaft. Pillow block ball bearings having extended grease lines shall support the fan shaft be interconnected via oil, heat, and static resistant belts. The motor shall be of the open-end, protected type. Belt guards shall be furnished as standard.
The steam-to-air heat exchanger shall be of a non-freeze type coil design incorporating finned-tube type elements each having tube within a tube construction. The finned-tube elements shall consist of 5/8 inch O.D. x 0.025 inch copper outer tubes with helically wound, mechanically bonded, aluminum fins spaced 10 per inch. The coil shall be composed of rows of finned-tube elements, two deep, attached to vertical steel headers with integral threaded inlet and outlet pipe nipples. A 16 GA galvanized steel casing shall support the assembly and rest on rails within the housing to facilitate coil removal.
The housing shall be formed of heavy gauge welded hot rolled, low carbon steel sheet. Construction shall be modular incorporating bolted and gasketed reinforced flanges at joints interconnecting sections of the housing. The housing shall be protected from corrosion by an application of an industrial air-dry enamel paint. The plenum shall be provided with two independent, motorized center pivoted, control dampers and an access door.
An electromechanical control system with a NEMA 4/12 control cabinet shall be furnished. A discharge air temperature sensor and an outdoor air temperature compensating controller shall control the modulation of the two independent damper motors. A low temperature safety shutdown thermostat; a magnetic, full voltage, fan motor starter; a control transformer; fuses and fuse blocks; and terminal strips shall be provided. A remote operating station with indicating lights shall also be included.
ACCESSORIES:
Heavy Duty Coils - Longer life, Cupro-Nickel coils are available for 75 psig and above steam pressures.
Room Thermostat - Automatic, remote room temperature control.
Service Platform - Raised flooring for maintenance and service.
Turning Elbow - For 90° redirection of airflow.
Filter Box w/Filters - Housing supporting reusable or throwaway type filter elements.
Recirculated Bypass Section - Louvered ductwork allowing reheating of room air.
Two and Four-Way Outlet Diffusers - Adjustable louvers providing directional control of discharge airflow.
JIC Disconnect Switch - Safety device which de-energizes unit without opening control cabinet.
Inlet Weatherhood - Downward turned elbow which minimizes entrainment of snow and rain.
Combination Motor Cover/Belt Guard - Enclosure providing increased weather protection for motor and operator safety around moving equipment.
Special Motors - Special constructions and manufacturers models furnished upon request.
