Navien Error Code E351: Abnormal Auto Feeder Valve

How to Fix Navien Code E351

1. Step 1: Check the system pressure gauge on your Navien boiler. It should typically be between 12-15 PSI when the system is cold.
2. Step 2: If the pressure is significantly below 12 PSI, try manually adding water to the system using the manual fill valve (refer to your Navien manual for its location). Slowly open the valve until the pressure reaches the desired range, then close it tightly.
3. Step 3: Inspect your radiators and accessible piping for any signs of leaks (water stains, drips). If you find any leaks, try to contain them and call a qualified technician immediately.
4. Step 4: If the pressure drops again quickly after adding water, or if you are uncomfortable performing these steps, contact a qualified HVAC technician to diagnose and repair the problem.

How to Reset Navien Code E351

1. Turn off the unit using the power button on the front panel.
2. Turn off the gas supply valve.
3. Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
4. Restore power at the breaker, then open the gas valve.
5. Turn the unit back on. If the error returns, the underlying issue needs repair.

Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.

What Does Navien Error Code E351 Mean?

The E351 error code on your Navien boiler indicates an issue with the automatic water feeder valve. This valve is responsible for maintaining the correct water pressure inside your boiler system. When the system pressure drops (due to leaks or usage), the auto feeder valve opens to add more water and keep the system running smoothly. If the system detects an abnormal operation of this valve, it will display the E351 error and potentially shut down to prevent damage. This error is important because low water pressure can cause the boiler to overheat, operate inefficiently, or even damage components. It's like trying to run your car with low oil – eventually, something will break. Addressing this issue promptly will help ensure your heating system operates safely and reliably.

Common Causes

• Faulty auto feeder valve: The valve itself may be defective and not opening or closing properly.
• Low water pressure in the supply line: If the incoming water pressure to the boiler is too low, the auto feeder valve may struggle to maintain the correct system pressure.
• Leaks in the heating system: A leak somewhere in your radiators, pipes, or boiler components can cause a continuous drop in pressure, forcing the auto feeder valve to work overtime and eventually trigger the error.
• Air in the system: Air pockets can interfere with pressure readings and the operation of the auto feeder valve.

Diagnostic Steps

Replacement Parts

Related Codes on Same Models

Other codes that affect the same Navien model families as E351.