Warning: This error locks out your Navien boiler/water heater, but there's no immediate gas or CO danger; call a professional to inspect the dual venturi system.
How to Fix Navien Code E762
Step 1: Turn off the unit at the power switch and gas shut-off valve to ensure safety.
Step 2: Check the air intake filter and area around the venturi for visible dust or blockage; clean if safe to reach (do not disassemble).
Step 3: Reset the unit by turning power off for 30 seconds, then back on. If code returns, call a Navien-certified technician.
How to Reset Navien Code E762
Turn off the unit using the power button on the front panel.
Turn off the gas supply valve.
Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
Restore power at the breaker, then open the gas valve.
Turn the unit back on. If the error returns, the underlying issue needs repair.
What does E762 mean?
The E762 code on your Navien unit indicates a dual venturi failure. The venturi is a part that mixes air and gas for proper combustion—on newer Navien models (like the NPF or NCB-E), there are two venturis, one for each burner stage. When the control board detects a mismatch or abnormal pressure signal from the venturi assembly, it triggers this lockout. This usually means the venturi is clogged with debris, has a faulty gasket, or the O-ring is damaged. In rare cases, the issue is a bad pressure switch or wiring. The unit won't fire until the problem is fixed.
Abnormal flue gas duct: Vent pipe not properly inserted
Auto RESET
Navien NHB-H Installation & Operation Manual
119
Vent Pipe Not Fully Inserted
Insert pipe 2-3“/4 (70 mm) into exhaust collar.
Navien NPF Installation & Operation Manual
128
Improper vent pipe installation
This error occurs when the vent pipes are not installed properly. ● Check if the vent pipes are installed properly on the furnace. ● If this error occurs continuously, contact Technical Support at 1-800-519-8794.