101
7.2
Replacing the Fuse Protecting Powered Relays
CAUTION:
Disconnect power to the controller before opening front panel!
Locate the fuse on the circuit board at the back of the controller enclosure under the plastic safety cover. Gently
remove the old fuse from its retaining clip and discard. Press the new fuse into the clip, secure the front panel of
the controller and return power to the unit.
Warning: Use of non-approved fuses can affect product safety approvals. Specifications are shown below. To insure
product safety certifications are maintained, it is recommended that a Walchem fuse be used.
Fuse
5 x 20 mm, 6A, 250V
Walchem P/N
102834
8.0 TROUBLESHOOTING
CAUTION
: Disconnect power to the controller before opening front panel!
Troubleshooting and repair of a malfunctioning controller should only be attempted by qualified personnel using cau
-
tion to ensure safety and limit unnecessary further damage. Contact the factory.
8.1 Calibration Failure
Calibrations will fail if the adjustments to the reading are outside of the normal range for a properly functioning system.
Refer to the instruction manual for the specific sensor being used for further information.
8.1.1 Contacting Conductivity Sensors
The calibration will fail if the adjustment to the gain is outside of 0.5 to 2.0.
Possible Cause
Corrective Action
Dirty electrode
Clean electrode
Improper wiring of sensor to controller
Correct wiring
Wrong cell constant entered
Program the controller cell constant setting at the value that
matches the electrode being used
Incorrect temperature reading or setting
Ensure that the temperature is accurate
Incorrect cable length or wire gauge setting
Set to the correct values
Faulty electrode
Replace electrode
8.1.2 Electrodeless Conductivity Sensors
The calibration will fail if the adjustment to the gain is outside of 0.2 to 10, or the offset is outside of -10,000 to
10,000.
Possible Cause
Corrective Action
Dirty sensor
Clean sensor
Improper wiring of sensor to controller
Correct wiring
Sensor placed too close to container walls
Relocate sensor
Sensor placed in the direct path of electrical current flow
Relocate sensor
Incorrect temperature reading or setting
Ensure that the temperature is accurate
Incorrect cable length or wire gauge setting
Set to the correct values
Faulty sensor
Replace sensor