Hoffer CAT3-DC-MIL, User Manual, Page: 24 / 29

16 Troubleshooting
HP-324-5
5. With an established flowrate, configure the digital multimeter
to measure AC volts, using the two volt scale. Connect the
positive lead to pin A of pickup coil. And the negative lead to
pin B of pickup coil. Depending on the flowrate an
approximate voltage reading of 10 millivolts to 1 volt should
be measured.
6. If zero volts are measured, a stalled rotor condition is
indicated. Remove the flow sensor from the piping. Refer to
flow sensor manual.
7-2-2 Symptom: Flow indication with no flow present
This symptom indicates the presence of electrical noise
pickup.
1. Disconnect the signal cable from the electronics unit and from
the flow sensor. Check the continuity of each lead of the
cable. If defective replace or repair.
2. With the signal cable disconnected from the flow sensor
measure the DC resistance of the pickup coil. The resistance
should read between 1500 and 2200 ohms between pin A and
pin B. A short or an open indicates a defective pickup coil
and the pickup coil must be replaced.
3. Verify cable shield connection.
4. Verify electronics unit enclosure connection to ships ground.