Mestek Combustion Air System

for Hydronic Applications

Combustion Air System Combustion Air System

Manufactured by Mestek in Dallas, TX, CAS is a factory-assembled combustion air preheater that is capable of heating outside air-and maintaining discharge air temperature regardless of fluctuations in inlet air temperature-to create the ideal boiler room conditions for operation. Each unit consists of a heater section containing an integral face and bypass coil with built-in multiple alternate finned heating elements and bypasses. Separate dampers control the airflow through these face and bypass sections, with each set of dampers interlocked and controlled by a separate electric or pneumatic damper motor.

Dampers fully open in cold weather

In colder temperatures, the dampers are fully open, exposing the coils to outside air so the air can be heated as it's drawn in.

Dampers partially closed in mild temperatures

As the outside air temperature rises, the damper position modulates to allow some bypass air, while the rest of the air is heated to achieve the appropriate temperature.

Dampers fully closed when no heating needed

If the outside air doesn't need any additional heating, the dampers seal off the coils completely, and the bypass sections open fully.

Key Benefits of Mestek CAS

  • Improves boiler performance 1% for every 40° temperature increase
  • Provides variable air volume for demand control combustion air
  • Creates more comfortable boiler room working conditions
  • Delivers reliable operation through maximum coil freeze protection
  • Installs easily with minimal piping, controls, and an integrated bypass section
  • Reduces exterior louver size needs by 70-80%
  • Includes variable frequency drive and room sensor, standard
  • Offers horizontal or vertical configurations
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