Sequence of operation for multizone unit VAV with proportional reheat control - Verasys - LC-ZEC410-x - Field Device - ZEC410

Verasys ZEC410 VAV Controllers Installation Guide
Brand
Verasys
Product name
ZEC410
Document type
Installation Guide
Part number
24-10143-1264
Document revision
C
Revision date
2019-10-04
Language
English

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 are box options. You have a cooling only box if you do not select either reheat or supplemental reheat.

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): Parallel fans cycle on when a call for heat occurs. The fan is off in all other states. Series fans run continuously in occupied mode. The fan moves from unoccupied mode to cycle on mode when it receives a call for heating or cooling.

Occupancy Lighting Switch (Optional): You can add an occupancy lighting switch to the box to temporarily set the VAV box to Standby mode when the occupancy is not detected. The zone switches back to occupied when the box detects occupancy. Standby mode uses standby temperature setpoints that are slightly highter or lower than the occupied cooling or heating setpoints, respectively. The VAV box also uses unoccupied flow setpoints in addition to the low temperatures.

Demand Control Ventilation (Optional): You can proportionally reset the minimum damper flows based on an air quality setpoint (CO2) when the zone (CO2) sensors wire to the boxes to detect the air quality in the zone. The reset of the damper minimum flows do not exceed the maximum value that you set. The CO2 sensor with the highest value determines the reset when more than one is wired.