21
Maintaining the Boiler
Checking 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.
Reviewing 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.
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 7 for
details about part locations.
Before flushing the Heat Exchanger, gather the
following items:
Ɣ
A bucket that is 10 gallons or larger
Ɣ
Cleaning solution diluted with water
Ɣ
3 hoses
Ɣ
A water circulation pump
Ɣ
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).
Inspecting the Ignition and Flame
Detector Electrodes
1. Remove the ignition and flame detector
electrodes from the boiler heat exchanger.
2. Remove any deposits accumulated on the
ignition/flame detector electrode. If the
electrodes cannot be cleaned satisfactorily,
replace with new ones.
3. Replace ignition/flame detector electrode,
making sure gasket is in good condition and
correctly positioned.
Checking the Ignition Ground Wiring
1. Check that the ground wire is in good condition
and securely attached to the boiler casing.
2. Check ground continuity of wiring using
continuity meter.
3. Replace ground wires if ground continuity is not
satisfactory.
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 State Data
Information 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.
Summary of Contents for NFC-250/200H
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