Dehumidification Control - Fan Coil Only; Temperature Setpoints - Johnson Controls TEC3000 Series Quick Start Manual

For automatic changeover, a supply temperature sensor or switch must be connected to the Changeover Sensor
(COS) input of the TEC. Changeover Mode must be set to Auto, and Supply Temp Type must be set for Analog
Sensor, Cooling N.C. (cooling when switch is closed), or Heating N.C. (heating when switch is closed). When an
analog sensor is used, the changeover setpoint can be adjusted. The changeover logic applies a 10-degree
Fahrenheit differential to the setpoint. The system switches to cooling mode when the temperature drops below the
changeover setpoint and remains in cooling mode until the measured temperature has risen 10 degrees above the
changeover setpoint.
You need to ensure that the Supply Temp type is set to Analog Sensor. The Changeover Mode is also exposed to
the BAS through the CGOVR-MODE and can be commanded from the BAS.
On two-pipe or VAV systems without an automatic changeover, or on four-pipe systems, you can use RSEN or
COS as a monitor-only point for reading an analog sensor. By setting the controller in four-pipe mode, or selecting
Heating or Cooling for Changeover Mode, the controller defaults to monitor-only mode for RSEN or COS and
exposes the value to the network as the supply temperature.

Dehumidification control - fan coil only

The TEC3000 controller support dehumidification control on fan coil devices under three configurations:
• Four-pipe fan coil
• Four-pipe fan coil with reheat
• Two-pipe fan coil (with changeover in cooling mode) with reheat
For optimal dehumidification performance, a 4-pipe unit with floating/incremental or 0 to 10 V control and a multi-
speed or variable-speed fan is recommended.
Dehumidification operates when the zone humidity increases above the zone humidity setpoint and the controller is
in the Idle or Cooling state. Dehumidification does not operate during heating and stops if the zone temperature
drops below the heating setpoint. When dehumidification is active, the cooling device controls to the humidity
setpoint, and the heating device reheats the zone in order to keep the temperature at the cooling setpoint. While in
the dehumidification mode, a multi-speed or variable-speed fan runs at the lowest possible speed to maximize
condensation and moisture removal across the cooling coil.

Temperature setpoints

The thermostat controller provides a flexible setpoint configuration to give power to the building owner while being
easy to use by the occupant. In addition to a simple up/down offset adjustment on the home screen for the
occupant, there are six temperature setpoints on the TEC. The six temperature setpoints are Cooling and Heating
setpoints for Occupied, Unoccupied, and Standby modes.
Note: The TEC enforces a 2-degree deadband between heating and cooling setpoints. If a setpoint violates this
standard (for example, cooling setpoint is set to 70 with a heating setpoint already set to 70), the opposing setpoint
is modified to comply with this deadband (in the previous example, the heating setpoint would automatically
change to 68).
TEC3000 Series Networked and Wireless Proportional Fan Coil and Individual Zone Thermostat Controllers with
Dehumidification Capability Quick Start Guide
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