ZEC410 VAV Controllers Installation Instructions
14
Sequence of Operation - Multizone Unit VAV with Proportional Reheat Control
Occupied Mode:
When the zone temperature is between the occupied heating and cooling setpoints (inside of the
bias), the primary air damper is at the minimum cfm and mechanical heating is unavailable. When the zone
temperature rises above the cooling setpoint, the primary air damper increases the cfm and mechanical heating is
unavailable. When the zone temperature drops below the heating setpoint, the supplemental heating coil is fully
used before the reheat coil enables. The damper is controlled to provide a minimum cfm.
Note:
The box reheat and supplemental reheat is a box option. If you select neither, you have a cooling only box.
Unoccupied Mode:
When in unoccupied mode, if the zone temperature is between the unoccupied heating and
cooling setpoints (inside of the bias), the primary air damper is at the minimum cfm and mechanical heating is
unavailable. When the zone temperature rises above the unoccupied cooling setpoint, the primary air damper
increases the cfm, if available, and mechanical heating is unavailable. When the zone temperature drops below the
unoccupied heating setpoint, the supplemental heating coil is fully used before the reheat heat coil enables. The
damper is at the minimum cfm.
Unit Enable:
A network unit enable sign controls the box mode.
Fan Control (Optional):
For parallel fans, upon a call for heat, the fan cycles on. For all other states, the fan is off.
For Series fan, during the occupied mode the fan runs continuously. During the unoccupied mode, the fan cycles
on with a call for heating or cooling.
Occupancy Lighting Switch (Optional):
You can add an occupancy lighting switch to the box. This temporarily
sets the VAV box to Standby mode when the occupancy is not sensed. When the box senses occupancy, the zone
switches back to occupied. Standby mode uses standby temperature setpoints that are slightly higher or lower than
the occupied cooling or heating setpoints, respectively. The VAV Box alos uses unoccupied flow setpoints in
addition to the low standby temperatures.
Demand Control Ventilation (Optional):
When Zone CO
2
sensors are wired to the boxes to sense the air quality
in the zone, the minimum damper flows are proportionally reset based on the air quality (CO
2
) setpoint. The reset
of damper minimum flows does not exceed the maximum value you set. The CO
2
sensor with the highest value
determines the reset if more than one sensor is wired.
ZEC Terminal Functions, Ratings, Requirements, and Wiring Guidelines
Input and Output Wiring Guidelines
Table 2 provides information about the functions, ratings, and requirements for the ZEC input and output terminals.
In addition to the wiring guidelines Table 2, observe these guidelines when wiring ZEC inputs and outputs:
•
Run all low-voltage wiring and cables separate from high-voltage wiring.
•
All input and output cables, regardless of wire size or number of wires, should consist of twisted, insulated, and
stranded copper wires.
•
Shielded cable is not required for input or output cables.
•
Shielded cable is recommended for input and output cables that are exposed to high electromagnetic or radio
frequency noise.
System and Zone Bus Supply Power Wiring Guidelines
Table 2 provides information about terminal block functions, ratings, and requirements.
In addition to the guidelines in Table 2, observe these guidelines when wiring the System/Zone Buses and supply
power:
•
Run all low-voltage wiring and cables separate from high-voltage wiring.
•
All FC and SA Bus cables, regardless of wire size, should be twisted, insulated, stranded copper wire.
•
Shielded cable is strongly recommended for all FC and SA Bus cables.
