AEC AD Series Operation And Installation Manual page 65

Problem
Poor dew point performance
(cont'd.).
Nothing displays when the
controller is turned on.
No setting change possible on
temperature controller.
Process value is abnormal or
not obtained.
AD Series Dehumidifying Dryers
Possible cause
Fouled dew point sensor
manifold.
Dirty filter.
The internal mechanism is not
inserted properly into the
housing.
The power supply is not
connected to its terminals
properly.
No power is supplied, or the
supplied power is not within the
specified range.
Disconnect switch or Control
Power switch not set to ON.
Control Power fuse blown.
The key protection switch is set
to ON.
Input polarity on thermo-couple
is wrong or connection is wrong.
Input-type setting is incorrect.
No compensating lead wires
used for extension of the
thermocouple.
Thermocouple and controller are
connected by wires other than
proper lead wires.
Process thermocouple not in
airflow.
Sensor is broken or short-
circuited.
The controller is influenced by
noise or other induction.
Celsius temperatures used
instead of Fahrenheit or vice
versa.
Process value shifted because
the input shift function is used.
Corrective action
Clear obstruction. Air should
flow freely through sensor.
Clean or replace filter element.
Properly insert the internal
mechanism into the housing.
Properly connect the power
supply to the power supply
terminals.
Supply a voltage of 85 to 125
VAC to the power supply
terminals of the controller.
Check control power fuse for
continuity. Turn disconnect
switch and control power switch
ON.
Set the key protection switch to
OFF.
Properly wire the terminals.
Properly set the input with the
input-type selector rotary switch.
Use proper compensating lead
wires and terminals.
Use a dedicated thermocouple
connector. If a connector is a
metal different from the
thermocouple and controller, a
temperature error may result.
Verify that the thermocouple is
properly installed in the inlet
tube.
Replace with a good sensor.
Separate input wires as far as
possible from the origin of the
noise.
Check Mode selector switch 6:
• ON - ºF
• OFF - ºC
Set input shift value to 0, or set
mode selector switch 4 to OFF.
Page 65