Navien Internal Water Leak

Navien water heater is leaking water from the bottom of the unit or from internal components; no error code displayed.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Corroded or cracked heat exchanger, Loose union or compression fitting, Failed pressure relief valve (PRV) discharging, Leaking internal recirculation pump or gasket

How to Fix / Troubleshooting

Safety: Turn OFF power, close the cold water inlet valve, and close the gas valve immediately if you see active leaking. Water can damage electronics and structure.

Steps:

  • 1. Isolate and inspect: Remove the front cover and use a flashlight to locate the source of the leak (heat exchanger, fittings, PRV, pump, etc.).
  • 2. Check fittings: Gently tighten accessible threaded or union connections that are visibly dripping. Do not overtighten plastic fittings.
  • 3. Inspect PRV: If water is discharging from the pressure relief valve outlet, check system pressure. A failed expansion tank or high inlet pressure may cause PRV discharge and requires a plumber.
  • 4. Dry electronics: If water has contacted the PCB or wiring, do not restore power until everything is completely dry and inspected.

Cracked heat exchangers, leaking pumps, or persistent PRV discharge require professional service and often part replacement.

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Repair Difficulty

Hard 4/5

Required Part

Primary Heat Exchanger
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