33 🟡 Repair Required
Rinnai Error Code 33: Heat Exchanger Thermistor
⚠️ Your Rinnai water heater is locked out due to a potential heat exchanger issue. It's safe to troubleshoot, but don't attempt to fix it yourself.
How to Fix Rinnai Code 33
- Check if your water heater is receiving power. The display should light up when you turn on the power switch.
- Try resetting the water heater by turning off the power at the circuit breaker, waiting 30 seconds, then turning it back on.
- If the error persists, do not attempt to fix it yourself. Call a professional HVAC technician.
What Does Rinnai Error Code 33 Mean?
Error code 33 on your Rinnai water heater indicates a problem with the heat exchanger thermistor. This sensor monitors the temperature of the heat exchanger and helps regulate the water temperature. If it's not working properly, your water heater may not heat water or could shut down to prevent overheating. This is a yellow hazard level because it's safe to troubleshoot, but you should call a professional for repairs.
Common Causes of Rinnai Code 33
- Faulty heat exchanger thermistor
- Wiring issue to the thermistor
- Corroded or damaged heat exchanger
Applicable Rinnai Models
Need a Pro to Fix Rinnai Code 33?
A licensed HVAC technician can diagnose and fix this issue quickly.
Find a Licensed Tech Near You →Replacement Parts for Rinnai Tankless Water Heater Code 33
Heat Exchanger Thermistor OEM: RIN-102565600
Wiring Harness OEM: RIN-102565700