Zehnder Rittling HC, Installation, Operation And Maintenance Manual

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27
Air system
balancing
All ductwork must be complete
and fully connected. All return
and supply grilles, lint screens
and panels must be properly
installed before air balancing to
ensure that the system is being
balanced at the true system
operating conditions.
Each individual unit and its
attached ductwork is a unique
system with its own operating
characteristics. Because of this,
air balancing is generally done by
a trained balance specialist who
are familiar with the procedures
required to properly establish the
fan system and air distribution
operating conditions. This should
not be attempted by unqualified
personnel.
To accurately commission the
primary air flow to the unit,
measure the static presure in the
primary air plenum through the
commissioning sample tube. To
achieve this, remove the sealing
plug from the commissioning
sampling tube and connect the
pressure-sensing instrument
(digital manometer) to the
commissioning sampling tube.
n
Do not attempt to measure
the static pressure in the
flexible duct connection.
Measure only at the provided
commissioning sampling tube
for commissioning purposes.
To obtain the designed primary
air and total air flow rate, adjust
the primary air volume balancing
damper integral to the unit as
necessary to obtain the primary
air plenum pressure to achieve
the specified/design primary air
flow using the plenum pressure
versus primary air flow curve
supplied for each unit. To adjust
the damper push or pull the
handle located at position 4.
Replace the plug to seal the
primary air commissioning
sampling tube on completion.
After proper system operation
is established, the actual unit
air delivery for each unit should
be measured and recorded for
future reference.
the piping mains to prevent this
material from entering the units
during normal operation.
During system filling, air venting
from the unit is accomplished
by the use of the standard,
manual air vent that is installed
at the top of each coil’s header,
if supplied by the manufacturer
or alternately through another
means supplied by the installing
contractor. To vent the air from
the coil, turn the slotted coin
vent until all of the air has been
vented from the coil. When water
begins to escape from the vent,
close the coin vent.
The air vents provided are not
intended to replace the main
system air vents and may not
release air trapped in other
parts of the system. Inspect
the entire system for potential
air traps and independently
vent those areas as required.
In addition, some systems may
require repeated venting over
time to fully eliminate air in the
system.
Cooling/heating
system
Prior to the water system start-
up and balancing, the chilled/
hot water system should be
thoroughly flushed to clean
out dirt and debris which may
have accumulated in the piping
during construction. During this
procedure, all unit service valves
must be in the closed position.
This will prevent any foreign
material from entering the unit’s
heat exchanger and clogging
valves and metering devices.
Strainers should be installed in