LX Series Unit Ventilator Controller User's Guide
25
Space Enthalpy Input
Use the space enthalpy input value and the outdoor space enthalpy to enable or
disable free cooling. The Rooftop Unit Controller also accepts input directly from
a space enthalpy sensor.
Space Humidity Input
Use the space humidity sensor to provide the UVC with the space relative
humidity. Relative humidity can be used as an input to the humidity control PID
loop.
The UVC can calculate space enthalpy when provided with relative humidity and
temperature. Space enthalpy can be compared to outside enthalpy to enable or
disable free cooling.
Space Temperature Input
The UVC uses the space temperature to control heating or cooling operations. One
of the following inputs must be present for the controller to work:
•
space temperature
•
nviSlave
The space temperature sensor can be a 10k ohm thermistor or provide a voltage or
current input to the board.
Water Temperature Input
The Unit Ventilator Controller provides heating or cooling through a single
two-pipe system with a heating or cooling valve. If this system is used, the device
must know the state, either hot or cold, of the available water. When the hardware
water temperature input is used, the Unit Ventilator Controller determines if the
water is hot or cold enough for heating or cooling.
The network inputs nviHotWater and nviWaterTemp are available for receiving the
water state or temperature. If nviHotWater state and value are zero, then the UVC
functions as if the water is cold. If nviHotWater state and value are not zero, then
the controller functions as if the water is hot. If the water temperature is colder
then the space temperature, the water is considered cold; if water temperature is
higher than the space temperature, the water is considered hot. Both inputs have
priority over the hardware input; however, if both values are received,
nviHotWater has priority over the nviWaterTemp.
