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REFRIGERATED AIR DRYER INSTRUCTION MANUAL
Ultra Air Refrigerated Dryers
201 Series Instruction Manual
Electronic Control Panel
The electronic control panel displays four different temperatures, allows the user to set and monitor the
timing of the drain valves, and controls the on/off operation of the compressor. The control panel operates
on 10V AC
The displayable temperatures are evaporator temp., refrigeration suction temp., ambient temp., and inlet
air temp. The displayed temperature can be changed by pushing the select switch, causing the corre-
sponding indicator light to illuminate. The temperatures can be displayed in degrees Fahrenheit or
degrees Celsius (a Celsius readout is achieved by turning on switch 1, located on the back of the panel; a
Fahrenheit readout is achieved by turning it off). The evaporator temperature is only displayed for 18 sec-
onds at a time. The panel also monitors the evaporator temperature and activates an alarm if it exceeds
70ºF (21ºC) or if the evaporator temperature is not being displayed, at which point the alarm light flashes.
When the evaporator temperature is displayed, the indicator light will be on continuously, regardless of
whether or not the evaporator alarm temperature is exceeded. When a sensor becomes defective (open
or shorted) or a temperature is out of range, the corresponding display for that temperature will read “Err”.
Each temperature can be calibrated individually. When switch 2 (located on the back of the board) is
turned on, it puts the dryer in calibrate mode, causing the temperature display to flicker. The mode select
switch is used to select the temperature to be calibrated, using the up and down arrows to select the des-
ignated temperature. After calibration is complete, turn off switch 2. The select switch is then used to
select the drain open set time, between .5 and 20 seconds.The drain open select time is displayed for 18
second at a time after the time has been selected or after the up or down switch is released.
Use the select switch to select the drain closed set
time. The time can be set from 1 minute to 2 hours
using the up and down buttons. The drain closed
select time can only be displayed for 18 seconds at a
time after the time has been selected or after the up
and down switch has been released.
The compressor on switch is used to turn the com-
pressor on and off. The compressor light turns on
and the compressor relay activates when the com-
pressor turns on. When the compressor is turned off,
the compressor light turns off and the compressor
relay is deactivated.
The drain test switch activates the drain relay for the
drain open set period. The drain open light turns on
when the drain relay is activated.
