Smart Equipment Controls
Installation, Operation and Maintenance Manual
Form No. SECIOM.A
Effective Date: 07/05/19
Page 6
Discharge Air Temp. Sensor
Factory or field supplied discharge air temperature sensors can be used to measure the temperature of the air being
discharged from the VAV box. The discharge air temperature sensor is wired between terminals ICOM1 and IN1 on the
SE-ZEC controller. The sensor should be mounted a minimum of 36” from the discharge of the unit and be centered in the
side of the ductwork. Avoid installing the sensor near an elbow, take off, or transition.
Factory provided nickel (1k ohm) temperature sensors have 4” long probes and stainless steel mounting flanges with (2)
provided hex-head self-drilling mounting screws. Sensors come equipped with 10 ft. plenum rated cables with ¼” internal
thread insulated quick-connect terminations on leads. Install sensor by drilling a hole into the ductwork, inserting the
sensor, and securing with provided screws. The sensor tip should not touch any part of the ductwork.
Occupancy Sensor
The SE-ZEC Controllers adjust the heating and cooling temperature setpoints, as well as the airflow setpoints based on
the zone occupancy. There are three different states of zone occupancy:
•
Occupied Mode
o
Uses Occupied Heating (68°F) and Occupied Cooling (72°F) temperature setpoints as well as Occupied
Heating and Occupied Cooling Airflow setpoints
o
For Series Fan Powered Terminals the Fan is always on
o
For Parallel Fan Powered Terminals the Fan is only on during a call for heating
•
Standby Mode
o
Uses Standby Heating (66°F) and Standby Cooling (77°F) temperature setpoints as well as Unoccupied
Heating and Unoccupied Cooling Airflow setpoints
o
For Series Fan Powered Terminals the Fan is always on
o
For Parallel Fan Powered Terminals the Fan is only on during a call for heating
•
Unoccupied Mode
o
Uses Unoccupied Heating (55°F) and Unoccupied Cooling (85°F) temperature setpoints as well as
Unoccupied Heating and Unoccupied Cooling Airflow setpoints
o
For Series Fan Powered Terminals the Fan is only on during a call for heating or cooling
o
For Parallel Fan Powered Terminals the Fan is only on during a call for heating
Table 1 below shows how occupancy states are determined for the SE-ZEC Controllers.
Table 1: SE-ZEC Occupancy Determination
SE-ZEC Occupancy Determination
Terminal Unit Type
Controller Type
ZEC500 (Standalone)
ZEC510 (Networked)
Single Duct Terminal Unit
The controller will switch from
Occupied to Unoccupied states by
comparing the measured airflow to
the
Occupancy Determination Flow
Setpoint
. When the measured airflow
is below the
Occupancy
Determination Flow Setpoint
the state
is set to Unoccupied. When the
measured airflow is above the
Occupancy Determination Flow
Setpoint
the state is set to Occupied
The building automation system
(BAS) will schedule when the
controller will switch from Occupied
and Unoccupied states. A room
occupancy sensor (wired to IN2 and
ICOM2 on the controller) can be used
to temporarily set the VAV box to
Standby mode when occupancy is not
sensed.
Fan Powered Terminal Unit
The controller will read the occupancy
sensor wired between IN2 and
ICOM2 on the controller to switch
between Occupied and Unoccupied
The building automation system
(BAS) will schedule when the
controller will switch from Occupied
and Unoccupied states. A room
