Navien NCB300-28K Service Manual page 102

10. Remove the rubber packing at the top of the cover and put
a Phillips screwdriver into the hole, and then loosen the
middle bolt located at the back of the burner.
1
11. Remove the ten bolts connecting the mixing chamber and
the heat exchanger, and then remove the mixing chamber,
burner and the chamber bracket.
3
2
12. Use the brush to dislodge the debris and pour water down
the channels to flush out the debris.
It is important to keep electric parts of the boiler
Note
●
safe from water.
Navien recommends to use a hose.
●
If the water pressure of the hose is too high, water
●
may splash to other electric parts of the boiler.
Keep the water pressure of the hose as low as it can.
If the boiler is installed in high area and you cannot
●
see the inside of the heat exchanger, use a solid
support and be careful not to fall.
13. As cleaning the heat exchanger is finished, reassemble the
parts.
14. Check the CO₂ . For more information on measuring the CO₂ ,
refer to "Checking the CO₂" on page 99.
This boiler requires very little maintenance, however
Note
a qualified technician should inspect the boiler at the
beginning of every heating season and/or when there
is a problem.
Inspection and Maintenance Schedule 101