Error Code
high
Hobart LXe – LXe Will Not Drain
On your LXe SERIES DISHWASHERS unit, a "machine will not drain" issue…
Hobart LXe - Error RINSE TEMP SENSOR: Final Rinse Thermistor Error
Caution / Monitor Closely
Warning: The information provided here is for educational purposes only.
Working with commercial kitchen equipment involves high voltage, gas, and high temperatures.
We strongly recommend contacting a certified service technician for any repairs.
We are not responsible for any damage or injuries resulting from DIY repair attempts.
This information is provided 'as is' without any guarantees of completeness or accuracy.
TLDR
On your LXe SERIES DISHWASHERS unit, the RINSE TEMP SENSOR error indicates the final rinse temperature probe is reporting values outside its operational range, signaling either an open or short circuit. This probe is critical for verifying proper sanitization temperatures. You should first inspect the sensor's wiring and connections for integrity before testing or replacing the thermistor itself.
Technical Details
Repair Steps:
- Isolate Power: BEFORE any inspection or repair, ALWAYS disconnect the dishwasher from its electrical power supply. Locate and turn off the appropriate circuit breaker or unplug the machine. Verify power is off using a multimeter.
- Locate the Final Rinse Thermistor: The final rinse thermistor (temperature sensor) is typically located within the rinse manifold or near the booster heater outlet where the final rinse water is delivered. Refer to your Hobart LXe series technical manual for its exact location and wiring diagram.
- Inspect Wiring and Connections: Carefully examine the wiring harness leading to the thermistor. Look for any visible damage, frayed wires, pinched sections, or loose connectors. Ensure all terminals are clean and securely seated. Corrosion on terminals can cause intermittent readings or open circuits.
- Check for Open or Short Circuit:
- Disconnect the Thermistor: Disconnect the thermistor from its harness.
- Measure Resistance: Using a multimeter set to ohms (Ω), measure the resistance across the two terminals of the thermistor. Compare this reading to the resistance chart provided in your Hobart LXe series service manual for the specified operating temperature (e.g., room temperature).
- Open Circuit: If the multimeter reads infinite resistance (OL or “open”), the thermistor has an internal break.
- Short Circuit: If the multimeter reads near zero ohms or a significantly lower resistance than expected, the thermistor may be shorted internally.
- Ground Fault: Also check for continuity between each thermistor terminal and the machine’s chassis ground. There should be no continuity; if there is, the sensor is shorted to ground.
- Inspect the Control Board Connections: If the thermistor and its immediate wiring appear good, inspect the corresponding connections on the main control board (or I/O board) for the final rinse thermistor input. Ensure connections are tight and free of corrosion or signs of overheating.
- Test for Environmental Factors: While less common for “open/short” errors, ensure there’s no excessive steam or moisture ingress around the sensor or its wiring that could cause intermittent faults.
- Replace the Thermistor: If the thermistor tests outside its specified resistance range, exhibits an open/short circuit, or shows signs of physical damage, it must be replaced. Ensure you use a genuine Hobart replacement thermistor designed specifically for your LXe series model.
- Restore Power and Test: After replacing components and ensuring all connections are secure, restore power to the dishwasher. Run a diagnostic cycle or a standard wash cycle to confirm the error has cleared and the final rinse temperature is being accurately monitored.
Common Questions:
Q: What is a thermistor and why is it important for my Hobart LXe?
A: A thermistor is a type of resistor whose resistance is highly dependent on temperature. In your Hobart LXe dishwasher, the final rinse thermistor is crucial for monitoring and ensuring that the rinse water reaches the required sanitization temperature (typically 180°F/82°C for commercial machines), meeting health code standards.
Q: Can I continue to use my dishwasher with a RINSE TEMP SENSOR error?
A: While the machine may continue to run cycles, it is strongly advised against using it for sanitization purposes. Without an accurate temperature sensor, the dishwasher cannot guarantee that dishes are reaching the necessary sanitization temperature, potentially leading to health code violations and ineffective cleaning. Repair the issue promptly.
Q: Is this a difficult repair for a commercial kitchen technician?
A: For an experienced commercial kitchen technician, diagnosing and replacing a final rinse thermistor is a relatively straightforward task, typically involving locating the sensor, performing resistance tests, and replacing the faulty part. Accessing the component may require disassembling certain panels, which should be done with caution.
When to call a technician
Consider calling a certified technician if:
- The error keeps coming back after you've tried the steps above.
- You're not comfortable doing the checks or repairs yourself.
- You notice unusual noise, smell, or behaviour.
- Equipment is under warranty and you want official service.
- You need the unit back in service quickly with minimal downtime.