Aircel AHLD E-Series Installation & Operation Manual page 21

Heatless Regenerative Desiccant Air Dryer
AIRCEL PROGRAMMABLE CONTROLLER (APC)
Dryer Operations, Cont.
STEP THREE: Opens Vessel 2 Repressurizing (241 - 300
seconds)
Vessel 2 (T2) purge exhaust pilot solenoid valve will de-energize,
causing Vessel 2 (T2) purge exhaust valve (V4) to close,
respressurizing Vessel 2 (T2).
The inlet tower selector pneumatic pilot valve maintains the
inlet valve (V1 & V2) positions.
STEP FOUR: Vessel 1 Extended Drying
A few seconds before the end of repressurization, the
integrated Energy Management Purge Reduction System's
moisture sensor determines the tower moisture load. If Vessel
1 (T1)'s moisture load is low enough, the tower will continue to
dry for an extended drying period until the moisture load has
reached a set high level or an additional 30 minutes, whichever
comes first. After 30 minutes, the unit will switch and continue
normal operation until the next extended savings step.
At the start of each extended savings step, the PLC checks for
faults, EMS relative humidity sensor value, and high outlet dew
point setting (optional) to ensure if the dryer needs to continue
drying. If so, the dryer will go into extended drying.
This feature reduces the overall purge consumption, saving
energy and money.
Note: If the dryer needs to continue to the next step to
regenerate based on humidity, the extended savings step
4 will be skipped.
| AHLD Series
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