Air system balancing
Heating system
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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.
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.
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.