Unit displays Code 33 and shuts down
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn OFF power and gas. Allow the unit to cool before touching the heat exchanger area.
Steps to check:
- Locate heat exchanger thermistor: It is typically clipped or bolted to the heat exchanger body.
- Inspect wiring and connector: Ensure the thermistor connector is secure at the sensor and control board. Look for signs of overheating or damage.
- Reset and test: After reseating connectors, restore power and gas and reset the unit.
When to call a professional: A technician should measure thermistor resistance and replace the sensor or control board if out of specification.
Repair Difficulty
Required Part
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