Cleaning The Air Intake Filter - Navien NFB-301C User's Information Manual

4.3 Cleaning the Air Intake Filter

The NFB boiler is equipped with an internal air filter to remove dust
and debris that accumulate inside the boiler. The dust and debris
accumulated inside the boiler should be removed from the internal
air filter every two years. Follow the instructions below to remove
the internal air filter and the dust and debris.
1. Unfasten the 4 latches (2 at the top, 2 at the bottom) to remove
the front cover and gain access the internal components.
2. Remove the five screws on the internal air filter using a Phillips-
head screwdriver.
12 Maintaining the Boiler
3. Remove the filter from the boiler and remove the dust and
debris accumulated in the filter.
CAUTION
If dust and debris are not removed regularly, it may result in
poor performance for the boiler.
If the internal air filter is fully blocked with dust and debris,
an error code may occur due to intake blockage being
detected in the boiler.