American Power Conversion DX, FM manual To set the dehumidify deadband for your System

Dehumidify deadband. The Dehumidify mode splits the deadband into equal segments according to the number of Modules in the System. A Module is then assigned to each segment of the deadband above the setpoint. When the return air relative humidity exceeds the relative humidity associated with that segment, the compressors in that Module engage and run until the relative humidity drops below that segment.

To set the dehumidify deadband for your System:

1.Determine the number of Modules in your System (1-3).

2.Multiply the number of Modules in your System by two.

3.Use this number as your dehumidify deadband setting. This assigns each Module a 2% RH segment of the deadband above the setpoint.

4.Adjust the deadband setting higher or lower to increase or decrease the speed at which the System can respond to rising relative humidity.

The following graphic is an example of a two-Module System that is using full dehumidification capacity (tandem compressors working together as one). The setpoint is 55% RH and the deadband is 4% RH. The compressors of each Module engage as the return air relative humidity reaches their segment of the deadband above the setpoint. When the return air humidity drops below the humidity assigned to them, those compressors disengage.

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Return air relative humidity

Caution: If a deadband setting is too narrow, it will cause the System to engage the compressors in response to a small humidity change. Since the compressors must run for a minimum period to avoid damage, this could overly dehumidify the room.

Caution: If a deadband setting is too wide, the System will not engage all of its dehumidification capacity until the return air humidity is significantly above the setpoint.

36 NetworkAIR FM DX 60 Hz Operation, Maintenance, and Troubleshooting