E762 🟡 Repair Required
Navien Error Code E762: Dual Venturi Failure
⚠️ 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.
What Does Navien Error Code 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.
Common Causes of Navien Code E762
- Clogged or dirty venturi due to dusty installation or poor air quality
- Damaged O-ring or gasket on the dual venturi assembly causing an air leak
- Faulty pressure switch (DPS) not reading correct differential pressure
- Loose or corroded wiring between the venturi sensor and main board
Applicable Navien Models
Source Documentation
This error code is documented in 6 official Navien technical manuals.
NFB-H Installation & Operation ManualPage 116
ReasonVent Pipe Not Fully Inserted
ActionInsert pipe 3 inches into exhaust collar.
Navien NCB-H Installation & Operation ManualPage 130
ReasonVent Pipe Not Fully Inserted
ActionContact technical support at 1-800-519-8794.
Navien NFB-H Installation & Operation ManualPage 116
ReasonVent Pipe Not Fully Inserted
ActionInsert pipe 3 inches into exhaust collar.
Navien NFC-H Installation & Operation ManualPage 128
ReasonAbnormal flue gas duct: Vent pipe not properly inserted
ActionAuto RESET
Navien NHB-H Installation & Operation ManualPage 119
ReasonVent Pipe Not Fully Inserted
ActionInsert pipe 2-3“/4 (70 mm) into exhaust collar.
Navien NPF Installation & Operation ManualPage 128
ReasonImproper vent pipe installation
ActionThis 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.
Need a Pro to Fix Navien Code E762?
A licensed HVAC technician can diagnose and fix this issue quickly.
Find a Licensed Tech Near You →Replacement Parts for Navien Tankless Water Heater Code E762
Dual Venturi Assembly OEM: 30017153A
Venturi O-Ring Kit OEM: 30017154A
Differential Pressure Switch (DPS) OEM: 30017155A