Specifications

Installation & Maintenance Manual
18
CDP 303: control is modulating. The controller has an input for an external modulating signal from a proportional
humidity controller or DDC system. The input signal can be selected by the dip-switches located on the back of the
controller. The only selectable parameter is the maximum steam production.
CDH 303: control is modulating. It is the most complete model and also includes the functions of a proportional
controller. Only a humidity sensor is connected. It displays the humidity value measured by the sensor and allows the
user to select the set-point and the differential.
CDD 303: control is modulating and there is an ON-OFF command for dehumidification. The proportional controller
function is included. CDD 303 actually offers the same functions as the CDH 303, but also has an ON-OFF relay
output for dehumidification control. This controller has been designed to control humidification and dehumidification in
air handling units and it is compatible with the MACROBASE temperature controller.
All modulating CDP or CDH controllers operate according to these graphs. Basically the humidifier turns on at 30% of
the differential or signal and turns off at 20%. Modulation is from 30% of the unit capacity to the Max Production
setting. Accordingly, a Max Production setting of 30% is essentially on/off operation. The CDD controller adds a
dehumidify output.