Dehumidification
Dehumidification is done only during cooling. Depending on type of equipment used, compressor speed, blower speed, setpoint adjustment, and equipment cycling are modified to provide added dehumidification. A dehumidification setpoint (separate from humidification setpoint) is available to the homeowner. It can range from 46% to 66% relative humidity. When actual humidity is higher than setpoint, a dehumidification demand exists. The Thermidistat Control responds by activating the dry contact (when enabled in Option 19). It may also control the compressor and blower, depending on equipment type and dehumidify selection choice. The 3 available selections are described below. A mandatory 5 minute blower off delay will be enforced if there has been a call for dehumidification during a cooling call. The amount of extra dehumidification available is very dependent on the type of equipment in the home. Without a variable−speed blower, the system’s ability to adjust dehumidification is very limited.
1.Normal Dehumidify Operation
When normal dehumidify is selected, the compressor will not turn on without a cooling demand. If dehumidify demand exists while cooling, dry contact will also be active (24VAC removed). This output commands variable−speed blowers to reduce their airflow, which improves water removal from the cooled air.
2.Cool to Dehumidify
The cool to dehumidify selection tells the system to operate the compressor, within limits, when there is a dehumidify demand even if there is no cooling demand. The limits are that the system may overcool up to 3_, but no more, while attempting to satisfy a dehumidify demand. Within this 3_ range, there is an additional balance between overcooling and humidity satisfaction. When overcooling must occur, the dehumidify
50
