First Company – Belt Drive Air Handlers – WH-XH


WH / XH Horizontal Double wall

Chilled Water / DX / Heat Pump Hot Water / Electric Heat Air Handling Units



  • Unit Cabinet Optional 1” double wall construction fabricated from a minimum of 18 gauge LFQ (lock forming quality) galvanized steel outer panels and a minimum 24 gauge inner liner fabricated from galvanized steel. Post and panel construction allows for large access panels to permit full access to internal components. The structural integrity of the cabinets remain unaffected by the removal of any or all access panels.
  • Insulation is a blanket-type made from glass fibers bonded with a thermosetting resin. Insulation shall be 1 inch, one and-onehalf pound density providing effective acoustical and thermal control, fire safety, and resistance to air erosion. In addition to a water-based adhesive, insulation is fastened to cabinet with mechanical fasteners. This insulation meets the requirements of ASTM C 1071, ASTM G 21, ASTM G22, NFPA 90A and UL-181.
  • Coils are 1/2 inch staggered tube type construction with seamless copper tubes and headers, and deep corrugated aluminum fins with straight edges. Fins are manufactured with full depth collars, drawn in the fin stock to provide accurate control of fin spacing and completely cover the copper tubes to lengthen coil life. The tubes are mechanically expanded into the fins for a permanent primary to secondary surface bond, assuring maximum heat transfer efficiency. The coils are to be tested at 350 pounds air pressure for operation at 300 PSI gauge working pressure.
  • Drain Pans are made from an UL94-5V rated, rigid PVC material with a three-way slope for positive drainage.
  • Fan Wheels are double width, double inlet (DWDI), forward curved, centrifugal type. They are statically and dynamically balanced for smooth, quiet operation. The Class I housing is constructed of heavy gauge steel with die-formed inlet cones.
  • Motors and Drives: Belt drive motors are standard duty, 1725 RPM, open, drip-proof construction. Single phase and most three phase motors are resilient mount with automatic reset thermal protection. Motor sheaves are variable pitch, cast iron with a splittapered hub. Blower and Motor mounting platform is constructed from 12 gauge LFQ (lock forming quality) galvanized steel. Platform is mounted to cabinet support rails with rubber in compression isolators for quiet vibration free operation. Blower exits cabinet through rubber-isolated frame.
  • Filter Section includes 2” pleated Merv 7 disposable type fiberglass filters. The 2” filter section is an integral part of the cabinet with easy tool free access.


  • Coils are available with 2 circuit options for high or low flow applications. 1/2 inch coil rows options include 1, 2, 4, or 6 rows with a maximum total of 10 rows.
  • Drain Pan Options include stainless steel with an insulating coating.
  • Electric Heat: Discharge mounted electric heat available in a wide range of KW’s and voltages. Available voltages are 120/1/60, 208/230/1/60, 277/1/60, 208/230/460/3/60, 575/3/60, 110/220/1/50, and 220/380/440-3-50.
  • Spring Isolators: Kits are available by unit size and coil rows with and without mixing boxes.
  • Motor Options include 2-speed, TEFC, or (HE) High Efficient. Voltage options include 120/1/60, 208/1/60, 240/1/60, 277/1/60, 208/3/60, 240/3/60, 480/3/60, 575/3/60. Contact Factory for availability of 50HZ motors.
  • Motor Control Box: For use with standard motors with internal overload protection. The 986FF control box is factory installed and wired. Features include a Disconnect switch, HOA switch, power fusing, motor contactor, 24V control transformer and low voltage terminal block.
  • Motor Control Starters: For use with non-standard motors without internal overload protection. The 986FR starter box is factory installed and wired. Features include a non-fused disconnect switch with thru-the-door pad lockable handle, HOA switch, built-in overload and magnetic trip, 24V control transformer and low voltage terminal block.
  • Filter Section options include Double Wall flat filter sections available for filters up to 4”. Double Wall angled filter sections accept 2” and 4” (4” for 16 and 20 only) deep filters. Filters are arranged in a “V” formation. Double wall access doors are standard on flat and angled filter sections.
  • Mixing Boxes are double wall construction with parallel blade, interconnecting outside-air and return-air dampers. Damper blades include stiffing breaks and are attached with 1/2” diameter steel rods rotating in nylon bushings and mounted in rigid galvanized steel frames. Dampers are rated as low-leakage, having a leakage rate not to exceed 2% of airflow. Damper blades are gasketed and include edge seal strips.



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