The L-Series of direct gas-fired make air systems was designed to furnish fresh, clean and heated  air from a controlled source by the most fuel efficient and cost effective means. The "L" systems employ a method of supplying heated air into a building by passing fresh air directly over a gas flame in the air stream. The burner utilizes the kinetic energy of the air flow to complete combustion with the products of combustion well within code prescribed safety limits. The direct gas fired burner provides the injection of proper combustion air at rates of firing over a wide turndown range of up to 22:1. Since all of the heat of the fuel goes into the air steam being heated, the direct gas fired unit has 100% combustion efficiency and 92% over all thermal efficiency (with 8% of the total heat lost in the latent heat of water formed in combustion).

" LR" system incorporate a return air damper downstream of the direct gas-fired burner which provides an option of either 50% fresh air and 50% return air, or 100% fresh air and no return air. Not available on UL listed units.

"LDF" system consists of the basic "L" direct gas-fired burner section without a blower section. The burner section is applied as a duct furnace in field- fabricated ventilation systems. Not available on UL listed units.

Standard Equipment

General:

Horizontal unit with HR-1 discharge

Housing:

Welded construction of 10 gauge hot rolled steel. Observation port and access panel furnished. Entire casing primed  inside and out and outside surface finished with a coat of enamel.

Blowers:

Centrifugal DWDI forward curved fan(s) through size L-233 and backwardly inclined fans on larger sizes, mounted on solid steel shaft(s) and supported by heavy duty y, self-aligning prelubricated ball bearings. V-belt drives are adjustable through 10 HP, fixed drives with 15 HP and larger motors, and sized for 135% of motor horsepower. Fan motor is mounted on an adjustable base outside the air stream. A belt guard is provided around the belt drive.

Motor:

T-frame, ODP prelubricated ball bearing type for all standard voltages.

Equipment Mounting Ledge:

The following items are mounted on the ledge outside of the air stream (1) main fan motor and drive assembly with belt guard (2) gas piping manifold (3) all necessary valves and miscellaneous controls not required in control box.

Burner:

Direct-fired line burner with spark ignited intermittent pilot for natural gas at inlet pressure from 6 oz. to 60 PSIG with up to 22:1 turndown ratio. (Note: Standard gas manifolds over 9,000 MBH input and some optional controls will require  special valves and/or larger than 6 oz. inlet gas pressure.)

Base Controls - Factory wired and flame - tested:

• Main gas hand shut-off value.
• Main and pilot gas pressure regulators.
• Pilot controls.
• Electric safety shut-off valve.
• Electronic modulating gas valve with temperature controller.
• High temperature limit switch.
• Air flow switch
• Ignition transformer.
• Electronic flame safeguard system.
• Motor starter.
• Control transformer.
• NEMA 1 control box.
• Remote control station with switches and indicating lights.

Options and Accessories

General:

Horizontal down vertical  up and vertical down blower arrangement as illustrated below.

Components:

• Unit weatherproofing including weatherproof service enclosure.
• Heavy duty motorized 2-position discharge shut-off damper.
• Safety rail for equipment ledge
• Opposite hand controls.
• V-bank filter section with throwaway cleanable or extended surface filters.
• Stormproof of weatherhood with louver blades and birdscreen.
• Stormproof intake elbow with birdscreen.
• Air discharge nozzle assembly
• Discharge hood with deflection grilles.
• Manual adjusted directional discharge blades.
• Vibration isolator pads. Grease line for remote fan bearing.
• Grease line for remote fan bearing.
• Variable pitch sheaves.

Motors:

Totally enclosed, two speed, explosion proof, automotive duty or chemical duty motors available on all units. (Two speed not available with UL approval.)

Burners:

Propane or propane standby. Propane standby not available with Maxitrol Selectra series.

Gas and Electrical Controls:

• FM or IRI approved controls
• UL requirements and label
• Hastings base JIC approval
• Ultra violet flame sensor. (Not available with UL approval)
• Low outlet temperature shut-off.
• Blocked intake switch and light.
• Circuit analyzer with lights
• Over-riding room thermostat
• Maxitrol Selectra Control System:
  a. Series 44. Includes discharge air monitor and space temperature selector and sensor.
• Fused disconnect switch or circuit breaker
• U.L. label main and remote panels

Coils:

Electric, steam, hot water and heat reclaim coils available for all models. (Fans motor is mounted inside on units with coils.) Not available with UL listed units.