Dewpoint Demand System
MODEL #PSO-DDCD*

The Dewpoint Demand System eliminates wasted energy from a dryer system with fluctuating or low load conditions. The dewpoint system senses the discharge dewpoint of the on-line desiccant bed and determines the maximum allowable drying cycle. If a dryer was sized for continuous full load conditions the desiccant bed would reach the end of its useful cycle in 4 hours for heat type dryers, or 10 minutes for heatless dryers. That time period is precisely what is required to regenerate a completely spent desiccant bed. So if a system were completely loaded, the on-line tower would reach the end of its useful cycle just as the regeneration tower was completing its regeneration of the off-line tower. In low load conditions the Dewpoint Demand Controller holds the on-line tower in the drying position and allows the other fully regenerated tower to hold in a pressurized standby mode consuming no energy until it is required as the on-line tower reaches the end of it’s useful adsorption cycle.
In low load conditions heated dryer systems can continue to dry a facilities compressed air for days while expanding no purge air or energy at all. This option also includes a 4-20ma output of dewpoint for a chart recorder or remote operation.

Humistat Demand System
MODEL # PSO-HDC*

The Humistat Demand control system is the cost efficient version of the Dewpoint Demand System. A humistat controller is used to monitor the outlet dewpoint of the on line tower. The humistat controller works off relative humidity and is less accurate than the true dewpoint monitor of the Dewpoint Demand Controller. It utilizes a fixed moisture content set point and has NO display.

High Dewpoint Alarm

MODEL # PSO-HAD*

The High Dewpoint Alarm is only available when a unit has the Dewpoint Demand control option. This option gives an indication of dewpoint higher than a field adjustable set point. This alarm is available with dry contacts for remote indication.

High Humidity Alarm
MODEL # PSO-HHA*

The High Humidity Alarm gives an indication of high humidity at the dryer discharge. The option utilizes a humistat to give indication of the moisture. The set point of the alarm is NOT field adjustable. This alarm is available with dry contacts for remote indication.

Fail to Shift Alarm
MODEL # PSO-HHA*

The Fair to Shift Alarm gives an indication of a failure in any of the tower switching or purge exhaust valves. It senses pressure in each of the towers and is interlinked to the cycle control. If there is too much or too little pressure in one tower than there should be an alarm condition exists. This alarm is available with dry contacts for remote indication.

Mode Indicating Lights
MODEL # PSO-PSSEQ*

The Mode Indicating Lights option adds Left/Right Tower Drying and Left/Right Tower Purging Panel Lights.

Heating Failure Alarm
MODEL # PSO-PSSEQ*

This option, which is only available in heat type dryers gives an indication that the heater has reached a high limit temperature and the heating system must be reset. This alarm is available with dry contacts for remote indication.

NEMA 4 & 7 Electrical, High Pressure
Systems & Low Dewpoint Systems

These available features are not options but design changes to basic dryer systems. To order these features refer to the model decoder on the corresponding product specification page.

*Refers to a missing NEMA electrical specification for the option that must match the dryer NEMA specification.