Dehumidification - Data Aire dap 4 Installation, Operation & Maintenance Manual

4. The humidification staging sequence of each adjustment period for ON/OFF of non-modulating
humidifiers is as follows:
Humidifier is ON at Humidity Setpoint – Humidity Deadband
Humidifier is OFF at Humidity Setpoint – 1.0%
5. The humidification staging sequence for a modulating humidifier is as follows:
Valve is OPENED at Humidity Setpoint – 1.0%
Valve is CLOSED at Humidity Setpoint – 0.5%
6. When the humidifier valve is opened, its position will follow a linear ramp that goes from 25%
open with the humidity at setpoint minus 0.5% to 100% open at setpoint minus humidity dead-
band.

DEHUMIDIFICATION

1. Dehumidification Mode can be programmed with one or two compressors for dehumidification
and with or without reheat limits (See Menu J – Factory Settings).
2. If dehumidification is programmed for "Within Reheat Limits" dehumidification cooling will be
inhibited if the return air temperature drops to temperature setpoint minus temperature dead-
band minus 2°F. Dehumidification will be inhibited until the return air temperature rises to the
temperature setpoint. Compressor short-cycle time will not be violated.
3. If dehumidification is programmed for "No Reheat Limits" it will remain ON until the humidity
setpoint is reached. In this mode dehumidification has priority and overcooling is disregarded.
The reheat sequence will remain the same.
4. If dehumidification is programmed for two (2) compressors, with or without reheat limits, only
one (1) compressor will be allowed if reheat is required.
5. There is a one (1) minute delay between stop-to-start of dehumidification. Compressor short-
cycle time delay will not be violated.
6. There is a five (5) minute delay between dehumidification and humidification.
7. The compressor staging sequence for dehumidification at each adjustment period is as follows:
UNITS WITH STANDARD (DUAL) SCROLL COMPRESSORS
Cool 1 ON at Humidity Setpoint + Humidity Deadband
Cool 2 ON at Humidity Setpoint + Humidity Deadband + 1%
Cool 2 OFF at Humidity Setpoint + 1%
Cool 1 OFF at Humidity Setpoint
UNITS WITH OPTIONAL TANDEM SCROLL or SEMI-HERMETIC (W/UNLOADING) COMPRESSORS
Cool 1 ON at Humidity Setpoint + Humidity Deadband
Cool 2 ON at Humidity Setpoint + Humidity Deadband + 1%
Cool 3 ON at Humidity Setpoint + Humidity Deadband + 2%
71 • dap4 User Manual