INEXPENSIVE TO OPERATE

Direct gas firing is 100% effective. In the majority of gas fired appliances which utilize heat exchanging devices approximately 20%, and usually more of the thermal content of the fuel is lost in vented flue gases as well as up to an additional 10-15% lost in piping or ducting. With direct firing, 100% of the fuel's energy is absorbed by the makeup air.

INEXPENSIVE TO INSTALL AND MAINTAIN

Only a gas line to the burner and an electrical hook-up to the air blower motor and controls are required. The burner does not require an air gas premixer, consequently, installation and maintenance are considerably simpler and more economical.

Combustion is electronically supervised to provide shut down in the event of flame failure. An adequate supply of circulating air is ensured by an air velocity interlock switch or the burner is automatically shut down. Excessive temperatures are guarded against by a manual reset high limit switch. The burner produces no harmful concentrations of carbon monoxide in the air stream. The nozzle design eliminates mechanical devices for mixing and controlling. No adjustment is required; it is impossible to maladjust.

A Direct Fired Makeup air unit is a combination of elements designed to condition fresh air introduced into the unit. This air is then blown into the occupied or unoccupied space replacing the air that is exhausted, through powered exhaust fans.

Makeup air units may, therefore be required to heat, ventilate, cool, humidify, dehumidify, pressurize, and filter the air blown into the space (supply air). The supply airflow will be either fixed or variable, which can respond directly to different exhaust flow rates in order to achieve room pressurization control.

Pressurization of a space eliminates:

- exhaust systems from exhausting incorrect air volumes
- building perimeters being cold in the winter due to high infiltration
- drafts at exterior doors
- doors from being hard to open from the outside

Air turnover units have become the preference for conditioning air in large buildings such as warehouses, manufacturing facilities and distribution centers. Air turnover units are preferred over unit heaters, forced draft ceiling hung units and infrared heaters for several reasons.

High temperatures build up directly under the ceiling, while at the floor level fluctuate from low to high extremes. Warm air stratification develops causing excess heat loss and condensation.

Drawbacks

· Multiple units required to cover large spaces
· Higher installation costs with multiple mountings, vents and utility connections
· Higher operating costs due to stratified building air increasing heat loss
· Increased maintain required due to multiple units and vent connections
· Reduced space comfort with hot air near ceiling and cold air at floor level

The air turnover unit operates by moving large volumes of air at low velocity. Cooler air at the floor level is drawn into the unit and heated an average of 10 to 30° F. The heated air is then discharged out the top

section of the unit to repeat the turnover cycle. By continuously rotating space air a building can normally reach a temperature differential from floor to ceiling of 3° F.

ETL certified

Casing

• Free standing structural angle iron frame
• Heavy gauge G90 bonderized steel cabinet
• Enamel finish

Propellers

• Quite high efficiency six blade propeller fans
• Vibration isolated fan deck
• 100,000 hr pillow block bearings
• T-frame 1.15 s.f. ODP motors on adjustable mounts
• Adjustable V-belt drives to 7-1/2 HP

Inlet/Discharge Section

• Expanded metal intake screen/fan guard
• Fan access door w/ interlock switch
• Expanded metal discharge screen

Burner

• Gas, propane or oil power burner
• Factory prepiped, wired and flame tested
• ANSI approved 7-14 in w.c. gas train

Heat Exchanger Section

• Four pass continuously welded 400 series
  primary with mild steel secondary heat exchanger
• Five year heat exchanger warranty
• Fully lined and insulated radiation shield
• Direct drive radial blade induced draft blower
• Puff door w/ inspection sight glass

Control Enclosure

• Deadfront fused disconnect switch
• Fused control transformer and starters
• Electronic flamesafeguard system
• Ignition transformer
• Numbered wire and terminal strip
• Manual reset high limit and auxiliary high limit switch
• Return air thermostat w/ sensing bulb

Outside/Return Air Damper Section

• 0-100% Outside air capability for summer
• ventilation and/or free cooling
• Options include;
• Fully modulating economizer control
• Two position motorized damper(s)
• Manual damper(s) with locking quadrant
• Inlet hood with birdscreen

Filters

• V-Bank filter section
• Flat bank filter section
• Pleated or permanent type filters

Coil Section

• Draw through or blow through
• Heating/cooling water coils, D/X cooling coils or steam coils.

Motor Options

• TEFC, high efficiency or two-speed

Burner Options

• Modulating with discharge air thermostat
• Hi-Low-Off with return air thermostat

Control Options

• Nema 4 or 12 control enclosure
• Remote control enclosure
• 10-point circuit analyzer
• Return and/or discharge smoke detector
• Seven day timeclock with nightstat