L.J. Wing IFB horizontal tube integral face and bypass coils offer the most effective preheat system ever developed. The IFB coil controls air temperature while full steam pressure or water flow is maintained in the coil at all times. The preset discharge air temperature is held constant regardless of variations in the inlet air temperature. Ideally suited for make-up air, combustion air make-up, penthouse units, air conditioning preheat and heating and ventilating units. Performance can be calculated by using the L.J. Wing specifier program.

For more information, request bulletin IFB.


  • Maximum freeze protection
  • Constant volume
  • Minimum temperature override
  • Minimum stratification
  • Accurate temperature control
  • Sizes from 408 to 50,400 CFM
  • Performance certified to ARI standard 410
  • ETL list to UL standard 1995
  • Five configurations, 126 sizes
  • Hydrostatically tested to 500 psig.
How it's Made

LJ Wing coils consistently perform as predicted because they are made and tested in our own facility in Dallas, Texas.

LJ Wing coils are standard with copper tubes and aluminum fins that are pressed onto the tubes. Fins for LJ Wing coils are flat, with no corrugations or lances. Since the coils are designed to handle outside air the possibility of dirt or debris collecting on the coils is real and the flat fin design makes it much easier to clean the coils and maintain optimum performance for many years. Coil tubes are soldered to the steel supply and return headers and pressure tested against leaks.

How It Works

When the outside air is too cold to enter the air handler without freezing the coil or damaging other components...

When the outside air is very cold and full heat is needed from the coil, the bypass dampers will close completely. This will expose the air to the full face area of the coil. Since the LJ Wing integral face and bypass coil is designed to operate at full steam pressure all the time the coil tubes are protected from damage caused by very low entering air temperatures.

How It Works

When the outside air is not quite warm enough to enter the air handler without partially raising the temperature...

As the outside air warms up the bypass dampers will begin to close and regulate the coil leaving air temperature according to a downstream thermostat setting. The bypass dampers will both block a portion of the steam or hot water coil face and open a path for the outside air to pass through without being heated. The "blended" hot and cold air will mix to maintain the target supply air temperature.

How It Works

When the outside air is finally warm enough to enter the coil and the unit without risk of damage....

When the outside air temperature is sufficiently warm enough to be introduced into the unit without risk of damage, the bypass dampers will open completely and allow all of the air to pass through without being exposed to the coil surface. The coil is still at full steam pressure but now will only provide a slight temperature rise. The dampers will continue to modulate as needed to maintain the target supply air temperature without the risk of freezing as the outside air temperature varies throughout the day and night.