Navien Water Heater Error Code 351: How to Fix It

Q: What causes Navien error code 351?

Error code 351 is caused by recirculation pump failure, loose electrical connections, pump blockages, control board malfunctions, or wiring damage that prevents the pump from operating properly.

Q: Can I reset Navien error code 351?

Yes, you can try resetting by turning off power for 5 minutes, then turning it back on and holding the power button for 5 seconds. However, if the underlying pump problem isn't fixed, the error will return.

Q: How much does it cost to fix Navien error 351?

DIY repair costs $100-300 for a replacement recirculation pump. Professional repair typically costs $200-500 including labor, depending on whether the pump, wiring, or control board needs replacement.

Q: Can I use my water heater with error code 351?

Your Navien unit may still provide hot water for immediate use, but the recirculation function won't work properly, leading to longer wait times for hot water at fixtures and reduced energy efficiency.

Q: How do I prevent Navien error code 351?

Prevent this error by scheduling annual maintenance, flushing the system to remove scale buildup, checking electrical connections periodically, and replacing water filters as recommended by the manufacturer.

Abstract

Navien error code 351 (also displayed as E351) indicates a problem with your tankless water heater's recirculation pump system. This error means the pump is not functioning properly due to mechanical failure, electrical issues, or wiring problems that prevent hot water from circulating efficiently through your plumbing system.