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.
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.
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.
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
