•2nd Stage Cooling: A simultaneous call from (G), (Y1), (Y2), and (O) to the (G), (Y1), (Y2), and (O/W2) terminals of the DXM control board will bring the unit on in 2nd Stage Cooling. When the call is satisfied at the thermostat the unit will continue to run in 1st Stage Cooling until the 1st Stage Cooling call is removed or satisfied, shutting down the unit.
NOTE: Not all units have
•1st Stage Heating: A simultaneous call from (G) and (Y1) to the (G) and (Y1) terminals of the DXM control board will bring the unit on in 1st Stage Heating.
•2nd Stage Heating: A simultaneous call from (G), (Y1), and (Y2) to the (G), (Y1), and (Y2) terminals of the DXM control board will bring the unit on in 2nd Stage Heating. When the call is satisfied at the thermostat the unit will continue to run in 1st Stage Heating until the call is removed or satisfied, shutting down the unit.
NOTE: Not all units have
•3rd Stage Heating (ECM fan models only): A simultaneous call from (G), (Y1), (Y2), and (W) terminals to the (G), (Y1), (Y2), and (W1) terminals of the DXM board will bring the unit on in 3rd Stage Heating (compressor plus auxiliary electric heat).
•Reheat Mode: A call from the Humidistat/ Dehumidistat to the (H) terminal of the DXM control board will bring the unit on in Reheat Mode if there is no call for cooling. When the Humidistat/ Dehumidification call is removed or satisfied the unit will shut down.
NOTE: Cooling always overrides Reheat Mode. In the Cooling mode, the unit cools and dehumidifies. If the cooling thermostat is satisfied but there is still a call for dehumidification, the unit will continue to operate in Reheat Mode.
ClimaDry Component Functions
The ClimaDry option consists of the following components:
•Proportional Controller
•Supply Air Sensor
•Motorized Valve
•Internal Loop Pump
•Hydronic Reheat Coil
The Proportional Controller operates on a 24 VAC power supply and automatically adjusts the water valve based upon the Supply Air Sensor. The Supply Air Sensor senses supply air temperature at the blower inlet providing the input signal necessary for the proportional control to drive the motorized valve during the reheat mode of operation. The Motorized Valve is a proportional
reheat coil during the reheat mode of operation. The proportional controller sends a signal to the motorized valve based on the supply air temperature.
The internal loop pump circulates condenser water through the hydronic reheat coil during the reheat mode of operation. In this application, the internal loop pump is only energized during the reheat mode. The Hydronic Coil is utilized to reheat the air to the setpoint of the proportional controller. Condenser water is diverted by the motorized valve and pumped through the hydronic reheat coil by the internal loop pump in proportion to the control setpoint. The amount of reheating is dependent on the setpoint and how far from setpoint the supply air temperature is. The factory setpoint is 72°F [22°C], generally considered “neutral” air.
ClimaDry Application Considerations
The reheat coil adds a small amount of resistance to the air stream. Consult the correction tables on page 8 of this manual for details.
Unlike most hot gas reheat options, the ClimaDry option will operate over a wide range of EWTs. Special flow regulation (water regulating valve) is not required for low EWT conditions. Temporary, slight overcooling of the space may result on rare occasions with ground loop (geothermal) systems during extremely low EWT conditions. Since dehumidification is generally only required in cooling, most ground loop systems will not experience these conditions.
� CAUTION! �
Water Source Heat Pump systems (including Wa- ter Loop Heat Pump systems) must have antifreeze protection to 20°F
ClimaDry Whole House Dehumidification - ClimateMaster Geothermal Heat Pumps - Rev.: 18 April, 2008B
