74 • dap4 User Manual
Open 20% if return_relative_humidity = humidity_setpoint – 0.8%
Open 30% if return_relative_humidity = humidity_setpoint – 0.7%
Open 40% if return_relative_humidity = humidity_setpoint – 0.6%
Open 50% if return_relative_humidity = humidity_setpoint – 0.5%
Open 60% if return_relative_humidity = humidity_setpoint – 0.4%
Open 70% if return_relative_humidity = humidity_setpoint – 0.3%
Open 80% if return_relative_humidity = humidity_setpoint – 0.2%
Open 90% if return_relative_humidity = humidity_setpoint – 0.1%
Open 100% if return_relative_humidity = humidity_setpoint
Chilled Water valve closing
While still in dehumidification mode, Chilled Water valve will start to close if dewpoint is de-
creasing OR relative humidity is decreasing closer to the setpoints minus deadband. The
modulation of the CW valve will be based on whichever has HIGHER demand for CW valve to
open. For example, if dewpoint requires the CW valve to open 20% and humidity requires the
CW valve to open 50%, as a result, CW valve will open 50%. Individual logic for CW valve
closing based on dewpoint and humidity is as followed:
CW valve modulation based on dewpoint
Start to close if return dewpoint drops to high_dewpoint_setpoint – high_dewpoint_deadband;
after that, the CW valve will:
Open 90% if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband – 0.1°F
Open 80% if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband – 0.2°F
Open 70% if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband – 0.3°F
Open 60% if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband – 0.4°F
Open 50% if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband – 0.5°F
Open 40% if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband – 0.6°F
Open 30% if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband – 0.7°F
Open 20% if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband – 0.8°F
Open 10% if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband – 0.9°F
Closed if return dewpoint = high_dewpoint_setpoint – high_dewpoint_deadband -1.0°F
CW valve modulation based on humidity
Starts to close if return_relative_humidity drops to humidity_setpoint – humidity_deadband;
after that, the CW valve will:
Open 90% if return_relative_humidity = humidity_setpoint – humidity_deadband – 0.1%
Open 80% if return_relative_humidity = humidity_setpoint – humidity_deadband – 0.2%
Open 70% if return_relative_humidity = humidity_setpoint – humidity_deadband – 0.3%
Open 60% if return_relative_humidity = humidity_setpoint – humidity_deadband – 0.4%
Open 50% if return_relative_humidity = humidity_setpoint – humidity_deadband – 0.5%
Open 40% if return_relative_humidity = humidity_setpoint – humidity_deadband – 0.6%
Open 30% if return_relative_humidity = humidity_setpoint – humidity_deadband – 0.7%
Open 20% if return_relative_humidity = humidity_setpoint – humidity_deadband – 0.8%
Open 10% if return_relative_humidity = humidity_setpoint – humidity_deadband – 0.9%
Closed if return_relative_humidity = humidity_setpoint – humidity_deadband– 1.0%
Humidifier Operation
Humidifier will turn on when dewpoint is below Low Dewpoint Setpoint
Humidifier will turn off when dewpoint is above Low Dewpoint Se Low Dewpoint Deadband
