E031 🟡 Repair Required
Navien Error Code E031: Inlet Thermistor Open/Short
⚠️ Your Navien boiler has detected an issue with the inlet thermistor and has shut down to prevent damage. Call a professional for repair.
How to Fix Navien Code E031
- Check if the boiler's power is turned off at the main circuit breaker
- Inspect the wiring harness and connections for any visible damage or corrosion
- Contact a licensed HVAC technician for a thorough inspection and repair
What Does Navien Error Code E031 Mean?
The E031 error on your Navien boiler indicates an open or short circuit in the inlet thermistor. This component measures the temperature of the water entering your boiler. When it's not functioning correctly, your boiler can't accurately monitor the water temperature, leading to system lockouts. This error is common in Navien boilers due to their advanced temperature control systems.
Common Causes of Navien Code E031
- Wiring issues or damage to the inlet thermistor
- Corrosion or mineral buildup on the thermistor
- Faulty control board or wiring harness
Applicable Navien Models
Source Documentation
This error code is documented in 5 official Navien technical manuals.
NFB-H Installation & Operation ManualPage 116
ReasonBurner Overheat
ActionCheck burner temperature fuse.
Navien NCB-H Installation & Operation ManualPage 129
ReasonBurner Overheat
ActionContact technical support at 1-800-519-8794.
Navien NFB-H Installation & Operation ManualPage 116
ReasonBurner Overheat
ActionCheck burner temperature fuse.
Navien NFC-H Installation & Operation ManualPage 127
ReasonOverheating of burner
ActionManual RESET
Navien NPF Installation & Operation ManualPage 125
ReasonOverheating of the burner
ActionThis error occurs when the overheat controller on the burner is initiated during combustion due to the burner overheating. ● If the furnace is continuously inoperable, contact Technical Support at 1-800-519-8794.
Need a Pro to Fix Navien Code E031?
A licensed HVAC technician can diagnose and fix this issue quickly.
Find a Licensed Tech Near You →Replacement Parts for Navien Tankless Water Heater Code E031
Inlet Thermistor OEM: 4010000001
Control Board OEM: 4010000002