Maintenance - Navien NFB-175 Mode D'emploi

9.9 Maintenance

Periodically check the damper condition inside the backflow
damper through the maintenance port to ensure optimal
performance of the system. Follow the instructions to check the
damper condition and replace the backflow damper if necessary.
1. Remove the screw that fixes the maintenance port cover to
the backflow damper, and then remove the gasket and the
maintenance port cover.
Gasket
Maintenance port cover
Fix screw
2. Through the maintenance port, check the operating condition
of the damper plate inside the backflow damper.
3. Reinstall the gasket and maintenance port cover, and then fix
Maintenance port
4. Visually inspect the maintenance port to ensure that the
Damper plate is
CLOSED.
Damper plate is
OPEN
them with a set screw.
gasket is properly installed between the maintenance port and
the maintenance port cover.
WARNING
Ensure that the gasket is properly installed under the
maintenance port cover, after checking the operating
condition of the damper plate through the maintenance port.
Harmful exhaust gas may leak if the gasket is not installed, or if
it is not installed properly.
Gasket
Installing a Common Vent System 79