Navien NCB700-42C Installation & Operation Manual page 59

Condensing combi boiler
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WARNING
Failure to inspect for the above conditions and have them
repaired can result in severe personal injury.
Checking the Water System
1. Verify all system components are correctly installed and
operational.
2. Check the cold fill pressure for the system. Verify it is correct
(must be a minimum of 0.8 bar).
3. Watch the system pressure as the boiler heats up (during
testing) to ensure pressure does not rise too high.
If the system contains glycol, test for proper
Note
concentration as recommended by manufacturer.
Excessive pressure rise indicates expansion tank
sizing or performance problem.
4. Inspect automatic air flues and air separators. Remove air
flue caps and briefly press push valve to flush flue.
5. Replace caps. Make sure flues do not leak. Replace any
leaking flues.
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.
58
Maintaining the Boiler
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
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 flue.
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 behaviour.
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.

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