Ranking of the Top Ten Common Failures of Dry Variable Temperature Controllers

Date: August 6, 2025 10:30:24

Dry variable thermostat common failure is more, the following is based on the frequency of occurrence and the degree of common, organized by the dry variable thermostat common failures:
  1. No display on thermostat: The power supply is not connected, the power switch is not open, the fuse is blown or the meter is damaged, etc. may cause this fault, you can check the power supply connection, the switch status, the fuse situation in turn, if they are all normal, then it may be a meter failure, you need to contact the manufacturer or replace the meter.
  2. Show "-OP-"The following problems can be solved: The input signal of the corresponding phase is usually larger than the measuring range of the thermostat, or the measuring circuit of the Pt100 temperature sensor has a large contact resistance. Can be solved by choosing the Pt100 temperature sensor matched with the thermostat and eliminating the contact resistance of the circuit.
  3. Show "-OH-": The cause of the failure is similar to the display of "-OP-", that is, the input signal of the corresponding phase is larger than the measuring range of the thermostat, or the sensor measuring circuit has a large contact resistance. Treatment is the same selection of matching sensors and deal with the line contact resistance.
  4. Show "-OL-"The following is an indication that the input signal of the corresponding phase is smaller than the measuring range of the thermostat or that there is a short-circuit in the measuring circuit of the temperature sensor. This can be dealt with by replacing the matching Pt100 temperature sensor and checking and repairing the short circuit.
  5. Flashing "-Er-": There may be an error in the wiring of the sensor measurement loop or there may be an internal fault in the thermostat. You can first check whether the external wiring of the thermostat is correct, if the wiring is correct, then you need to contact the manufacturer for technical support.
  6. Fixed display of the temperature of a phase: Generally because the thermostat is in the maximum display state, the thermostat can be returned to the traveling display state by pressing the Max/Road key.
  7. All three phase temperatures are below the set value, but the fan is still running: The cause is most often that the fan startup setpoint or return differential has been changed, or the fan is in manual startup. The setpoint can be readjusted or the fan can be put under automatic control by pressing the AUTO/MANUAL key.
  8. Display of three-phase temperature imbalancePt100 platinum resistance may not be fixed into the temperature measuring hole, resulting in inaccurate measurement, or there may be a difference in the temperature of the three phases of the transformer itself. You can re-fix the platinum resistance, if the problem is still not solved, you need to confirm whether it is the normal temperature difference of the transformer itself.
  9. The fan is running automatically even though the fan temperature has not been reached.: It is possible that the fan is in manual start-up state, or the system fan timer start/stop function is on. If it is manually turned on, you can press the relevant button to turn off the fan; if it is a timed function, it is a normal phenomenon.
  10. The fan cannot be turned off manually after it has been started manually: Usually because the measured temperature value at this point is exactly between the temperature at which the fan is automatically started and stopped, which is normal, and the fan will automatically stop when the temperature is lowered to a certain level.
Tags::