10
DDT40 Adaptive Defrost Control
DDT40 CONTROL FUNCTIONALITY
Modes
•
Efficiency Mode –
Scheduled Defrosts are bypassed when the control is in this state. This is indicated when the blue
LED is ON continuously. If there is no thermistor probe attached or a probe failure occurs, the DDT40 control module
operates solely off of the defrost timer and does not enter efficiency mode.
•
Calibration Mode –
The DDT40 control module enters calibration mode after the first Scheduled Defrost and after each
allowed defrost cycle. During calibration the control establishes a baseline coil behavior.
•
Thermistor Probe Initialization –
The number of thermistor probes connected to the control is detected during the
initial startup of the system. The blue LED flashes the number of times equal to the number of probes detected. If the
correct number of probes are not detected, disconnect power to the control before you attempt to correct the problem.
Optional: Manual Defrost
To initiate a manual defrost, rotate the FM timer dial clockwise through two consecutive scheduled defrost cycles within 60
seconds.
Optional: Multiple Evaporators
The DDT40 control has four sensor inputs that can monitor up to four evaporator coils. Typically, in a four-evaporator system,
the timer activates a contactor that energizes the multiple defrost loads simultaneously. When the DDT40 control senses
a decrease in capacity in one or more coils, efficiency mode shuts off and the defrost timer initiates a defrost at the next
scheduled interval.
Sensor Wires
DDT40 with
I
CUBE™ Technology
Remote Condensing Unit
(Indoor or Outdoor)
FIG. 14
Evaporator System
For additional assistance, contact Technical Services at 1.815.675.7000.
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