Warning: Your Navien tankless water heater has detected a problem with the DHW thermistor and has shut down to prevent damage.
How to Fix Navien Code E047
Check if the error persists after turning the power off and back on again.
Inspect the wiring harness connecting the DHW thermistor to the control board for any signs of damage or corrosion.
If the error remains, contact a licensed HVAC technician to diagnose and repair the issue.
How to Reset Navien Code E047
Turn off the unit using the power button on the front panel.
Turn off the gas supply valve.
Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
Restore power at the breaker, then open the gas valve.
Turn the unit back on. If the error returns, the underlying issue needs repair.
What does E047 mean?
The E047 error on your Navien tankless water heater indicates an open or short circuit in the DHW (Domestic Hot Water) thermistor. This component is responsible for measuring the water temperature and signaling the control board to adjust the heating process. When the thermistor fails, it can cause the system to shut down to prevent overheating or freezing. Don't worry, this isn't a gas leak or fire risk, but it does require professional attention.
This error occurs when the exhaust temperature sensor does not operate properly. ● Turn off the furnace, turn it on again and check if the furnace operates properly. ● If the furnace is continuously inoperable, contact Technical Support at 1-800-519-8794.