Navien · Tankless Water Heater Critical
E760 — Water Leak Detected
The internal leak sensor at the base of the unit detected water. The unit shuts down to prevent damage.
- Keep using it?
- No — service first
- DIY difficulty
- Moderate
- Verified against
- navieninc.com ↗
How to fix it
- Power off the unit and shut off water supply.
- Open the cabinet and locate the source of water with a flashlight and paper towel.
- If condensate trap is overflowing, clear it (see E193).
- Tighten or reseal any leaking fittings; replace failed O-rings.
- If the heat exchanger itself is leaking, it must be replaced (often a warranty claim — check coverage first).
- Dry the leak sensor and base completely before restoring power.
- If no leak is found and the sensor is wet from condensation, address the moisture source and dry the sensor.
Why it happens
Typical signs: E760 on display · Water pooling under unit · Drip visible inside cabinet · Repeated shutdowns after restart
- Leaking heat exchanger Pinhole or cracked exchanger — often from freezing or long-term scale corrosion.
- Leaking fitting or O-ring Loose union, failed gasket on a port, or weeping pressure relief.
- Condensate spillage Plugged condensate trap overflowing onto the leak sensor.
- False trip from condensation External condensation dripping into the cabinet.
- Failed leak sensor Sensor shorted by corrosion.
Parts you may need
If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.
More Navien tankless water heater codes
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: navieninc.com.