RTU
The Verasys system supports dehumidification operation on RTUs equipped with a factory installed HGR coil and a SMART Equipment control board.
Dehumidification is initiated when the humidity rises 5% above the dehumidification setpoint and continues until the humidity is 5% below the dehumidification setpoint. The request for dehumidification starts the fan, hot gas relay, and appropriate cooling stages based on the user-set mode.
The dehumidification sequence supports two modes: normal and alternate. In both modes, requests for dehumidification with no cooling turns on the first compressor (C1) and the HGR coil. When one stage of cooling (Y1) is requested, the mode is checked. If the mode is set to normal, the HGR coil is turned off or remains off. The request for cooling is then satisfied by the economizer, if present, or the first compressor. If the mode is alternate, the first compressor, HGR coil, and the second compressor (C2) are turned on. For both normal and alternate modes, a call for two stages of cooling (Y2) turns off the HGR and turns on the first and second compressors.
See Table 1 for a summary of the dehumidification sequence in both modes.
| Request | Alternate Mode | |||||
|---|---|---|---|---|---|---|
| HGR | C1 | C2 | HGR | C1 | C2 | |
| Dehumidification | On | On | Off | On | On | Off |
| One Stage of Cooling (Y1) | Off | On | Off | On | On | On |
| Two Stages of Cooling (Y2) | Off | On | On | Off | On | On |