Navien E762
Navien E762: vent pipe not properly inserted
Short answer
Navien E762 means the vent pipe is not properly inserted into the heater's vent collar. It exists on NPE-2 models, which have a detector at the collar. On a new install it points to an incomplete vent connection; on a working unit it means something moved or separated. Navien's manual says to contact technical support.
In this guide
Exhaust from a gas water heater must leave the building through a sealed vent. E762 means the heater has detected that the vent pipe is not seated correctly where it connects to the top of the unit.
The meaning and recommended action below come from Navien's User's Information Manual for NPE-2 condensing water heaters (NPE-180A2, NPE-210A2, NPE-240A2 and the S2 models). Navien technical support: 1-800-519-8794.
This code is listed for the current NPE-2 generation. The original NPE-A and NPE-S models do not have it.
A vent that is not sealed can let exhaust, including carbon monoxide, into the building. Turn the heater off and do not use it until the vent is checked. Make sure working CO alarms are installed.
What to do
- Turn the water heater off with the power button.
- Do not try to force the vent pipe in yourself.
- Call your installer or Navien technical support.
Why it matters
Navien's manual warns not to operate the heater without proper venting and to stop using it if vent pipes are damaged or separated at a joint. The detector only checks the connection at the unit, so the rest of the vent run still needs regular inspection. See our tankless water heater venting requirements guide.
Before you call
Have the model number and serial number from the rating plate on the side of the unit ready, along with the date it was installed and the exact code. Navien asks for this information when you contact technical support, and your installer should be your first call for warranty service.
See every code on our Navien error codes page.
Common questions
Can I use my Navien with E762?
No. Turn it off and have the venting checked, because an unsealed vent can release exhaust into the home.
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Other Navien codes
| Code | Meaning |
|---|---|
| E003 | Ignition failure |
| E004 | False flame detection |
| E012 | Flame loss |
| E016 | Heat exchanger overheat |
| E030 | Abnormal exhaust temperature |
| E031 | Burner overheating |
| E046 | Limit control (high limit switch) abnormal |
| E047 | Exhaust temperature sensor (thermistor) open or short |
| E060 | Dual venturi abnormal operation |
| E109 | Fan motor abnormal operation |
| E110 | Exhaust blockage (condensate blockage) |
| E407 | Hot water outlet temperature sensor open or short |
| E421 | Cold water inlet temperature sensor open or short |
| E432 | Cold water inlet 2 sensor open or short |
| E434 | Water adjustment valve fault |
| E438 | Circulation pump fault |
| E439 | Flow sensor fault |
| E441 | Second hot water temperature sensor open or short |
| E445 | Bypass mixing valve fault |
| E515 | Control board (PCB) abnormal operation |
| E517 | DIP switch setting fault |
| E593 | Front panel key fault |
| E594 | EEPROM (memory) fault |
| E615 | Input and memory fault |
| E736 | Cascade communication fault |
| E740 | Outdoor temperature sensor fault |
| E760 | Flushing or service alarm |
| E762 | Vent pipe not properly inserted |
| E773 | Using the wrong gas |
| E782 | Main panel communication fault |
| E785 | Flow switch or flow sensor fault (with AHU) |
| E788 | Gas type mismatch between board DIP switch and front panel |