Navien E762 (vent pipe not properly inserted): what to check

Navien display

E762

“Vent pipe not properly inserted”

NPE-A2, NPE-S2, NPN · NPE-2 User's Information Manual, p. 18; NPN User's Information Manual, p. 23
Technician

What it means

E762 comes from the Vent Installation Detector (VID), a switch in the heater’s vent collar. A correctly sized vent pipe pushed fully into the collar presses against the switch. If the pipe is not fully inserted, the heater shows an error and will not operate NPE-2 Installation & Operation Manual, p. 44; NPN Installation and Operation Manual, p. 37. Navien also warns that the wrong size of vent pipe material can trigger E762 NPE-2 Installation & Operation Manual, p. 45; NPN Installation and Operation Manual, p. 38.

The VID is there to help the installer seat the pipe. Navien states that it is not an alarm, a safety switch or a substitute for a carbon monoxide detector NPE-2 Installation & Operation Manual, pp. 44–45; NPN Installation and Operation Manual, p. 37. It also warns that the VID may not stop the heater if the vent pipe is partly or completely dislodged NPE-2 Installation & Operation Manual, p. 45; NPN Installation and Operation Manual, p. 37, and the NPE-2 manual says to inspect all vent pipe connections periodically p. 45. No E762 on the display does not prove the vent is sound.

Check these first

The table’s remedy for E762 is a call to Navien Technical Support at 1-800-519-8794 NPE-2 User’s Information Manual, p. 18; NPN User’s Information Manual, p. 23. The manuals give owners no repair step. What you can safely do:

Look at the vent pipe where it enters the heater, and along the run you can see, without pulling or pushing on it. If any vent pipe, elbow or intake pipe is damaged, separated at a joint, or shows corrosion, rust or melting, turn the heater off and stop using it NPE-2 User’s Information Manual, p. 5; NPN User’s Information Manual, p. 5.
Leave the pipe for a professional to reseat. Navien says that if the vent pipe is not fully inserted into the collar, the unit displays an error message and does not operate NPE-2 Installation & Operation Manual, p. 44. Navien warns against operating the heater without proper venting because of the fire and carbon monoxide risk NPE-2 User’s Information Manual, p. 5.
Check that a carbon monoxide detector is installed in the living area near the heater. The NPE-2 installation manual calls for one NPE-2 Installation & Operation Manual, pp. 16, 41.
Call Navien Technical Support or the professional who installed the heater NPE-2 User’s Information Manual, p. 48.

When to call a licensed technician

Any E762. Reseating or replacing vent pipe is venting work: on NPE-2 models only licensed professionals should install venting NPE-2 Installation & Operation Manual, p. 42, and on NPN models venting is for a qualified service agency NPN Installation and Operation Manual, p. 16.
A technician should confirm that the vent pipe size and material match the manual. NPN heaters must not be vented with PVC, CPVC, ABS or galvanized material NPN Installation and Operation Manual, p. 35. For NPE-2 heaters Navien lists solid-core PVC or CPVC (Schedule 40 or 80), UL1738 PVC or CPVC, approved polypropylene and approved stainless steel, and rules out cellular-core PVC, cellular-core CPVC and Radel for the exhaust vent NPE-2 Installation & Operation Manual, p. 52.

Notes for different models

The pipe sizes differ. On NPE-2 models the manual describes the correctly sized pipe for the VID as 2.0 inches NPE-2 Installation & Operation Manual, p. 44. On NPN models it is a 5.0 inch diameter pipe, inserted at least 1.3 in (34 mm) into the collar NPN Installation and Operation Manual, p. 37.

E762 is in both user’s manual tables but not in the NR-21DU remote manual’s code table NR-21DU Remote Controller Manual, pp. 30–32.

Related Navien codes

All Navien codes

Navien is a trademark of its owner. How House Works is not affiliated with or endorsed by Navien.