21
Air system balancing
All ductwork must be complete and
fully connected. All return and supply
grilles, filters and access doors 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 is familiar with the
procedures required to properly
establish the fan system and air
distribution operating conditions.
This should not be attempted by
unqualified personnel.
After proper system operation is
established, the actual unit air
delivery and the actual fan motor
amperage draw for each unit should
be measured and recorded for future
reference.
Heating system
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.
Prior to the water system
start-up and balancing, the
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
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 or the optional automatic
air vent that is installed at the
top of each coil’s header. Manual
air vents are capped Schrader
valves. To vent the air from the
coil, unscrew the cap, turn the
cap over and insert the pointed
end of the cap into the vent to
depress the valve until all of the
air has been vented from the coil.
When water begins to escape
from the vent, release the valve
and replace the cap. Automatic
air vents may be unscrewed one
turn counterclockwise to speed
up the initial venting but should
be screwed in for automatic
venting during normal operation.
Start-up
