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5. When an alarm condition has not been corrected
and the “alarm reset” button is pressed, the alarm
will not clear except as follows:
a. The alarm conditions will clear for 5 seconds,
then reappear if the alarm condition persists, this
applies to the following alarms:
i. Heater: High Inlet Temperature.
ii. Heater: Low Temperature
iii. Humidity Sensor: High Humidity Alarm
iv. Humidity Sensor: Under-Range or Over-
Range Alarm
v. Dew Point Sensor: High Dew Point Alarm
vi. Dew Point Sensor: Under-Range or Over-
Range Alarm
6. There are three alarms for each tower that are trig-
gered by the tower pressure switches. These alarms
can occur in any operating mode (Test, Fixed, Energy
Management, or Dew Point Demand Cycle).
Following is a brief description of each alarm.
a. Left or Right tower, drying, low pressure
i. Pressure switch open during the drying cycle.
b. Left or Right tower, regenerating, high pressure
i. Pressure switch closed while purge valve is
open (after an initial time delay)
c. Left or Right tower, regenerating, low pressure
i. Pressure switch open at the end of the
regenerating cycle.
d. On alarm condition, de-energize heat cycle,
stop cycle sequence, display local alarm and
de-energize common alarm relay.
e. Alarm is self-clearing.
7. Depressurization Failure (models 900 - 3200) -
Left Tower or Right Tower Regenerating High
Pressure Alarm
a. If pressure switch 3PS is open during the Heating
of Cooling Cycle, indicating pressure above the
factory setting (refer to Electrical Schematic
drawings at the back of this manual for set point),
an alarm is activated.
b. On alarm condition, the heater is de-energized,
the purge shut-off valve (Solenoid “E”) is closed,
the cycle sequence is stopped, a local alarm is
displayed and the common alarm relay is de-
energized.
c. “Alarm Left Tower - Regenerating High Pressure”
will be displayed if regenerating the left tower.
“Alarm Right Tower - Regenerating High Pressure”
will be displayed if regenerating the right tower.
d. This alarm is self-clearing.
8. The dryer is equipped with RTD temperature
sensors. There are out of range alarms for each.
a. The standard left tower, right tower, and heater
RTDs (RTD1, RTD2, RTD3) are scaled from
-20°F(-28°C) to 890°F (477°C), “Out of Range”
conditions are as follows:
i. Over-range - temperature above 850°F
(454°C)
ii. Under-range - temperature below -20°F
(-28°C)
iii. Note: The controller will annunciate a “Heater
Overtemperature” alarm in lieu of an “Over
Range” alarm when the heater sensor is
disconnected.
b. The Energy Management RTD4 is scaled from
-20°F(-28°C) to 429°F(220°C), “Out of Range”
conditions are as follows:
i. Over-range - temperatures above 400°F
(204°C)
ii. Under-range - temperatures below -20°F
(-28°C)
c. On alarm condition, a local alarm is displayed and
the common alarm relay is de-energized.
d. Over-range and Under-range alarms are self-
clearing.
9. Heat Low Temperature
a. RTD3 is used to detect Heater Low
Temperature.
b. Alarm if the heater temperature is less than 250°F
(121°C) within 15 minutes after the Heat Cycle is
initiated (15 minute delay also applies after power
recovery).
c. On alarm condition, display local alarm and de-
energize common alarm relay.
d. This alarm is self-clearing.
10. Cooling Alarm - Heater High Temperature
a. RTD3 is used to detect Heater High
Temperature.
b. Alarm when heater temperature exceeds 250°F
(121°C) when the sequence is in the second
stage of the COOLING CYCLE (i.e. 30 minutes
after cooling starts.
c. On alarm condition, stop cycle sequence, display
local alarm and de-energize common alarm
relay.
d. This alarm must be manually reset.