Underhill ICC Decoder Module Troubleshooting Guide
18
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Connect the 2Wire path to the fault-‐finding transformer (yellow box above).
Clamp the red lead wire from the fault-‐finding transformer at least one foot
away from the transformer.
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Measure the current with the clamp meter along the 2Wire path at the valve
closest to the controller and at the valve furthest away. The value you measure
is the number of decoders x 3mA. For example, if the controller is managing 30
stations, then a value of around 90 mA should be observed. If the value is
initially 95 mA at the station closest to the controller but 0mA at the valve
furthest away, then there is a break in the 2Wire path. Measuring at intervals
along the 2Wire path will indicate where the short lies. If the value measured
at the valve furthest away is generally the same, then there is no short on the
2Wire path.
•
Disconnect the fault-‐finding transformer from the 2Wire path and reconnect
the 2Wire path to the L1/L2 terminals on the decoder module.
•
Using the clamp meter and clamp around one of the conductors on the 2Wire
path, then operate station 01 manually from the ICC controller. Write down
the mA value displayed on the clamp meter and repeat the process for every
station on the 2Wire path. If the red “Error” LED comes on, reset it and
continue this task. Mark the station(s) with the “Error” message. The
corresponding decoder may need to removed and verified its working by taking
it back to the ICC module and operating it in Manual – Single Station mode
with a known working solenoid. If it does not operate, then replace. While the
decoder is removed, conduct an ohms check on the valve solenoid to verify it’s
functioning. Generally a “good” solenoid will have a value between 25-‐35. If
the value is much higher, replace the solenoid.
•
You may encounter more that one station being managed by a single decoder
or several decoders with the same address.
•
Temporarily disconnect one of the solenoids from the decoder and operate the
station manually again. Write down this value. Using the clamp meter,
conduct an ohms test on the disconnected solenoid.
•
Repeat the process on the other solenoid sharing the same decoder. Replace if
necessary.
