16
Ductwork
connections
All ductwork and or supply and
return grilles should be installed
in accordance with the project
plans and specifications. If not
included on the unit or furnished
from the factory, supply and
return grilles should be provided
as recommended in the product
catalog.
For units with no return air
ductwork, check local code
requirements for possible
application restrictions. All
units must be installed in non-
combustible and non-hazardous
areas.
Some models are designed to
be connected to ductwork with
a minimum amount of external
static pressure. These units
may be damaged by operation
without the proper ductwork
connected. Consult the approved
submittals and the product
catalog for unit external static
pressure limitations.
Units provided with outside
air should have some form of
low temperature protection to
prevent coil(s) from freezing.
This protection may be a low-
temperature thermostat to close
the outside air damper, a preheat
coil to temper the outside air
before it reaches the unit, or any
other protective method.
It should be noted that none of
these methods will adequately
protect a coil in the event of
power failure. The safest method
of freeze protection is to use
glycol in the proper percent
solution for the coldest expected
air temperature.
Flexible duct connections should
be used on all air handling
equipment to minimize vibration
transmissions. Insulation and
ductwork should be installed
to allow servicing of equipment
including motors, blowers, filters,
etc.
Zehnder Rittling assumes no
responsibility for undesirable
system operation due to
improper design, equipment
or component selection, and/
or installation of base unit,
ductwork, grilles and other
related components.
