Installation & Operation Manual
12 Maintenance
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 the Knight XL Service Manual. Adjust settings if necessary. See Section 1 of the Knight XL Service 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 -
2.Verify cold fill pressure is correct and that operating pressure does not go too high.
70 
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.’s
4.When replacing the burner, ensure gasket is in good condition and positioned correctly (FIG.’s
Figure 12-2 Burner Assembly - Model 399
AIR / GAS ARM
BURNER 
GASKET
SCREWS
(QTY. 5)
Figure 12-3 Burner Assembly - Model 500
AIR / GAS ARM
BURNER
GASKET
SCREWS 
(QTY. 5)
