4
DDT40 Adaptive Defrost Control
Wiring
1. Route supply and load wires as appropriate for your installation. Refer to the wiring diagrams on page 7 for examples of
typical installations.
2. Strip the supply and load wires 1/2" from the end.
3. Connect the wires to the proper terminals and tighten them securely.
Install the Thermistor Probe
1. Plan and route the length of field-supplied copper
wire needed to connect the thermistor probe from
the evaporator coil to the input lead. (This wire may
be 18–14 AWG shielded or unshielded up to 400 ft
(121.92 m) long).
Note:
The field-supplied wires may run along with the
power wires through existing or new conduit.
2. Connect the input lead to the DDT40 control as shown
in FIG. 7. The input lead may be inserted into any of the
four connectors on the DDT40 control.
Note:
Make sure the input pins are properly aligned with
the input lead connector.
Input Lead
Input Lead Connectors
FIG. 7
Attach the Input Lead
3. Route the input lead above the tab and around the FM
timer as shown in FIG. 8.
4. Cut the input lead length to ensure the connection is
inside the enclosure, as shown in FIG. 8.
5. Use the provided wire connectors to connect the input
lead to the routed field-supplied wire.
6. Connect the thermistor probe to the evaporator coil.
There are two options for probe placement.
Note:
Ensure the copper tube surface area designated
for thermistor probe placement is clean. Use Emery
cloth or Evaporator cleaner to clear the surface. A
dirty surface will create an insulation barrier which
may cause inaccurate temperature readings.
–
Insert the probe between the cooling fins, as shown
in FIG. 9. Ensure that the probe makes good contact
with one of the evaporator tubes. Then, using needle
nose pliers, carefully bend the cooling fins together
to hold the probe firmly in place.
–
Use the provided clip, or if the clip is the incorrect
size, use another means to fasten the thermistor
probe to one of the circuit tubes e.g., hose clamp,
insulation tape, zip tie, as shown in FIG. 10. Clip the
probe onto one of the lower coils in either the
10 o’clock or 2 o’clock position, making sure that
the probe makes good contact with the evaporator
tube.
Wire Connector
Input Lead
Route Lead over Tab
FM Timer
Field-Supplied Wire
to Thermistor Probe
FIG. 8
Route Input Lead
Probe
Cooling Fins
FIG. 9
Insert Thermistor Probe between Evaporator Cooling Fins
