E762 Vent pipe not fully inserted (VID)

What the control is telling you

The Vent Installation Detector does not sense the exhaust pipe fully inserted in the collar. NHB-H manual: insert 2-3/4 in (70 mm). NFB-H error table says 3 in, but its venting section says 2-3/4 in (70 mm).

Applies to: Navien NHB-H (NHB-055H/080H/110H/150H) and NFB-H fire-tube (NFB-175H/200H) condensing boilers

Likely causes

• Exhaust pipe not pushed fully into the collar
• Wrong size pipe (VID needs a correctly sized 2.0 in pipe) or deformed/damaged pipe
• Pipe misaligned or moved vertically
• Common vent collar kit fitted without the VID jumper wire

Test and repair steps

1. Warning: A pipe that is not fully seated can leak carbon monoxide. Do not run the boiler until it is fixed.
2. Cut the pipe square, deburr, mark 2-3/4 in (70 mm) from the end, wet with water (not grease) and twist it in until it bottoms and the mark is hidden.
3. Put a straight piece on the collar. Do not fit a street elbow right at the collar.
4. Tighten the collar clamp with an 8 mm socket.
5. Replace a damaged or out-of-round vent pipe.
6. With a Navien common vent collar kit, connect the supplied VID jumper wire to the wire labelled VID.
7. Bubble-test all vent joints with the boiler running. The VID does not detect leaks or separated joints further along the vent.

Settings for these units

Installation clearances (indoor) · Navien NHB-H

Bracket gives 5/8 in (16 mm) from the wall; studs at 16 in on centre.

Common vent installs: 36 in above the top and 24 in in front are recommended for service.

Installation clearances (indoor) · Navien NFB-H

Do not install on carpet; indoors only.

Remove the wood pallet and refit the 6 screws to keep the cabinet airtight.

Models that show this code

6 models in Navien NHB-H, Navien NFB-H

Other codes on the same units

• E594 EEPROM fault
• E615 Memory fault
• E736 Cascade communication fault
• E740 Outdoor sensor not detected
• E777 Low water cutoff activated
• E782 Front panel communication fault
• E784 Zone controller communication fault
• E786 Improper front panel detected