Green Flow Solution logo
Schedule Service

Troubleshooting code

Back to all NPE-S2 Series error codes

Navien NPE-S2 Series E441 troubleshooting

Domestic hot water inlet/outlet 2 sensor open or short. Use this page to document the issue and prepare for service. GreenFlow should handle diagnosis for electrical, refrigerant, lockout, or recurring conditions.

Schedule Service +1 (857) 767-6414

What the code means

E441: Domestic hot water inlet/outlet 2 sensor open or short

The Navien manual for this product family lists E441 as: Domestic hot water inlet/outlet 2 sensor open or short.

System area
Temperature / sensor
Service level
Service recommended

Safe checks before calling

  • Record the exact Navien code, whether the unit is locked out, and when the code appeared.
  • Confirm thermostat, controller, or front-panel status without changing service settings.
  • Check only visible intake, exhaust, filter, clearance, condensate, and water-supply conditions that can be inspected without opening panels.
  • Take photos of the code, equipment nameplate, venting, surrounding equipment area, thermostat or controller, and any visible leak, ice, or obstruction.

When to stop and call GreenFlow

Call GreenFlow if the code repeats, the unit is locked out, hot water, heating, or cooling is not restored, or the concern involves gas, flame, combustion, venting, electrical components, refrigerant, pressure, water leaks, PCB/control boards, sensors, pumps, or warranty coverage.

Share the visible code, model and serial number if available, photos, current symptoms, and whether the issue affects heating, cooling, or both.

E441 questions

What does E441 mean on a Navien NPE-S2 Series?

The Navien manual for this product family lists E441 as: Domestic hot water inlet/outlet 2 sensor open or short.

What should I safely check before scheduling service?

Record the displayed code, confirm thermostat or controller status, check only visible intake, exhaust, filter, clearance, and water-supply conditions, and take photos of the code and nameplate. Do not open gas, electrical, refrigerant, combustion, or internal equipment panels.

When should GreenFlow handle this code?

Call GreenFlow if the code repeats, the unit is locked out, hot water, heating, or cooling is not restored, or the concern involves gas, flame, combustion, venting, electrical components, refrigerant, pressure, water leaks, PCB/control boards, sensors, pumps, or warranty coverage.

Brands We Service

Popular cities

Service Areas

Our Happy Customers

Terry S.

Excellent service from best tech!

Jack B.

Andrey always does a great job.

Melissa S.

The repair person came quickly and was super efficient and polite, and showed me what to do next time. He gave my dog a quick pay and was off again.

Randy J.

Thanks to Andrey for an amazingly quick response to my request for a service call. He diagnosed and fixed my issue within 24 hours of my asking for help. Excellent service. Thanks.

View All