Lochinvar KNIGHT 51-211 - Manual (Page 31)

2
Maintenance
31
Service Manual
Inspect ignition and flame sense
electrodes
1. Remove the ignition and flame sense electrodes from the
boiler heat exchanger access cover.
2. Remove any deposits accumulated on the ignition/flame
sense electrode using sandpaper. If the electrodes cannot
be cleaned satisfactorily, replace with new ones.
3. Replace ignition/flame sense electrode, making sure
gasket is in good condition and correctly positioned.
Check ignition ground wiring
1. Inspect boiler ground wire from the heat exchanger access
cover to ground terminal strip.
2. Verify all wiring is in good condition and securely
attached.
3. Check ground continuity of wiring using continuity
meter.
4. Replace ground wires if ground continuity is not
satisfactory.
Check all boiler wiring
1. Inspect all boiler wiring, making sure wires are in good
condition and securely attached.
Check control settings
1. Set the SMART SYSTEM control module display to
Parameter Mode and check all settings. See Section 1 of
this manual. Adjust settings if necessary. See Section 1 of
this manual for adjustment procedures.
2. Check settings of external limit controls (if any) and
adjust if necessary.
Perform start-up and checks
1. Start boiler and perform checks and tests specified in
Section 10 - Start-up of the Knight Wall Mount
Installation and Operation Manual.
2. Verify cold fill pressure is correct and that operating
pressure does not go too high.
Check burner flame
1. Inspect flame through observation window.
2. If the flame is unsatisfactory at either high fire or low fire,
turn off boiler and allow boiler to cool down. Remove
the burner and clean it thoroughly using a vacuum
cleaner or compressed air. Do not use compressed air to
clean burner if performed inside a building.
3. Remove the burner, reference FIG. 2-2 below.
4. When replacing the burner, ensure gasket is in good
condition and positioned correctly (FIG. 2-2).
Figure 2-2 Burner Assembly
Check flame signal
1. At high fire the flame signal shown on the display should
be at least 10 microamps.
2. A lower flame signal may indicate a fouled or damaged
flame sense electrode. If cleaning the flame sense
electrode does not improve, ground wiring is in good
condition, and ground continuity is satisfactory, replace
the flame sense electrode.
3. See Section 3 - Troubleshooting in this manual for other
procedures to deal with low flame signal.