28
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.
Horizontal hideaway units with
plenum can be field converted from
bottom inlet to rear inlet or vice
After system integrity has been
established, the piping should
be insulated in accordance with
the project specifications. This is
the responsibility of the installing
or the insulation contractor.
Zehnder Rittling will not accept
any charges associated with
re-insulating piping if the
installing contractor failed to
establish system integrity prior
to insulating. All chilled water
piping and valves not located
over the drain pan or drip pan
must be insulated to prevent
damage from sweating. This
includes factory and field piping
inside the unit cabinet.
The condensate drain should always
be connected and piped to an
acceptable disposal point. For proper
condensate flow, the drain piping
should be sloped away from the unit
at least 1/8 inch per foot. A P-trap
may be required by local codes and
it is strongly recommended for odor
containment. Condensate drain lines
should be at least the same diameter
as the drain connection. Properly
sized traps should be used to allow
proper removal of the condensate
from the drain pan. The bottom of the
trap should be at least (1” + cabinet
static pressure) below the drain
pan connection. The top of the trap
should be at least 1” below the
drain connection when cabinet
is under positive pressure and ½
the distance of the bottom of the
trap from the drain connection
when cabinet is under negative
pressure. The condensate drain
hose should be secured with a
clamp after installing.
versa. Remove the filter retaining
clips, filter, filter retaining
C-channel and the rear/bottom
return panel. Rotate the panel
and C-channel to the bottom/rear
mounting location leaving the
1” wide filter slot at the back or
bottom of the unit.
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.
