Underhill ICC Decoder Module Troubleshooting Guide
17
Program the controller to turn on the pump/master valve output along with several
stations from a programmed start time. As stations are operating, measure the
current draw along the 2Wire path.
This may require disconnecting half the stations or a branch in the 2Wire path to
isolate a decoder(s). Remove and replace the located decoders as needed. Remember
to program them with the corresponding station number first.
Observed Field Condition
17) “I replaced the ICC module recently and came back to the controller only to
determine the ICC module is no longer operating. Why do I keep “blowing-‐up” ICC
modules?”
Possible Causes
1) The ICC module is not grounded to a separate ground rod, (not electrical ground
but “earth-‐ground”.
2) You may have several decoders with the same address and one of more has a
defective decoder and/or solenoid. (Remember as a solenoid reaches end-‐of-‐life, it has
more resistance drawing excessive current).
How To Troubleshoot
Damaged decoders typically take a lower or higher current than the 2.9 to 3.1 mA
values.
1)
Confirm the ICC module has a #12 solid copper ground wire to a ground rod or
ground plate. The ground rod should be a copper-‐clad 8” long x 5/8” diameter
ground rod driven full-‐depth. Connect the ground wire without any sharp bends or
angles. If local soil conditions prevent installation of a ground rod, consider using
a ground plate. Both should be installed a minimum of 10’ away from the
controller. Sometimes site conditions prevent this distance so shorter distances are
acceptable as exception not the rule.
2)
To troubleshoot the 2Wire path you will need the following troubleshooting
equipment:
Fault-‐finding transformer
Digital Clamp Leak Detector
Underhill p/n TRANSFRMR-‐115V
Underhill p/n TW-‐DCM
•
Temporarily disconnect the 2Wire path connected to L1/L2 on the decoder
module.
