Navien NBH Series, User'S Information Manual

Page: 19 / 27

Maintaining the Boiler 19
Flushing the Heat Exchanger
CAUTION
Flushing the heat exchanger is a somewhat complicated
procedure. Read the following instructions carefully before
attempting this procedure. If you are uncertain about any of
the steps in the procedure, contact an authorized technician or
licensed professional. Keep in mind that improper maintenance
can void your warranty.
Refer to the “2.2 Parts of the Boiler” on page 6 for details about
part locations.
Before flushing the Heat Exchanger, gather the following items:
Ɣ
A bucket that is 5 gallons or larger
Ɣ
Cleaning solution diluted with water
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3 hoses
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A water circulation pump
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2 flush valves (if not installed)
Note
Before flushing the heat exchanger, additional flush
valves (“A” and “B”) must be installed on the near boiler
piping (included with Navien Manifold System).
A
B
C
D
Checking all Boiler Wiring
Inspect all boiler wiring, making sure wires are in good condition
and securely attached.
Checking the Control Settings
1. From the front panel, enter the Diagnostics Mode and check all
settings. Adjust settings if necessary.
2. Check settings of external limit controls (if any) and adjust if
necessary.
Performing Start-up and Checks
1. Start boiler and make sure that the boiler is operating properly.
2. Verify cold fill pressure is correct and that operating pressure
does not go too high.
Check the Burner Flame
1. Inspect flame through observation window.
2. If the flame is unsatisfactory at either high fire or low fire, check
for obstructions in the venting and ensure that the air intake
filter is clean.
Review with the Owner
1. Review the User’s Information Manual with the owner.
2. Emphasize the need to perform the maintenance schedule.
3. Remind the owner of the need to call a licensed contractor
should the boiler or system exhibit any unusual behavior.
4. Remind the owner to follow the proper shutdown procedure
and to schedule an annual start-up at the beginning of the
next heating season.