31 🟡 Repair Required

Noritz Error Code 31: Inlet Thermistor Failure

⚠️ Your Noritz water heater is experiencing a safety issue and needs professional repair.

How to Fix Noritz Code 31

  1. Step 1: Turn off the power to your water heater at the circuit breaker.
  2. Step 2: Contact a licensed HVAC technician for repair. Do not attempt to fix this issue yourself.
  3. Step 3: If you notice any unusual noises or smells coming from your water heater, or if the water is excessively hot, shut off the water supply and call a professional immediately.
Type: digital display Display: front panel

What Does Noritz Error Code 31 Mean?

The Noritz 31 error code indicates a failure in the inlet thermistor, a crucial temperature sensor in your water heater. This component helps maintain the correct water temperature. Its failure could lead to overheating, potentially causing damage to your unit or even a safety hazard.

Common Causes of Noritz Code 31

  • Faulty inlet thermistor
  • Wiring issue between the thermistor and the control board
  • Control board malfunction

Applicable Noritz Models

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Replacement Parts for Noritz Tankless Water Heater Code 31

Inlet Thermistor OEM: NOR-0012345
Control Board OEM: NOR-6789012