12 Maintenance
Figure 12-2 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 of the Knight Wall Mount Service Manual for other procedures to deal with low flame signal.
Review with owner
1.Review the Knight Wall Mount User’s Information Manual with the owner.
2.Emphasize the need to perform the maintenance schedule specified in the Knight Wall Mount User’s Information Manual (and in this manual as well).
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
Installation & Operation Manual
Cleaning boiler heat exchanger
For recommended materials; including brush, appropriate extension(s), refractory cover, and detailed instructions see Table 12B - Heat Exchanger Cleaning Kits.
1.Shut down boiler:
•Follow the “To Turn Off Gas to Appliance” instructions for the boiler in Section 10 - Startup.
•Do not drain the boiler unless it will be exposed to freezing temperatures. If using freeze prevention fluid in system, do not drain.
2.Allow time for the boiler to cool to room temperature if it has been firing.
3.Remove the nuts securing the heat exchanger access cover to the heat exchanger and set aside.
4.Remove the heat exchanger access cover, burner, and gas/air arm assembly.
WARNING The boiler contains ceramic fiber materials. Use care when handling these materials per
instructions in the Service Manual. Failure to comply could result in severe personal injury.
5.Remove the condensate hose from the heat exchanger end. Connect a field supplied 3/4" diameter hose to a drain pan. Using field supplied means, cover the refractory in the back of the combustion chamber of the heat exchanger.
6.Use a vacuum cleaner to remove any accumulation on the boiler heating surfaces. Do not use any solvent.
7.Brush the heat exchanger while dry using a nylon bristle brush. Caution: DO NOT use a metal brush.
8.Finish cleaning using a clean cloth dampened with warm water. Rinse out debris with a low pressure water supply.
9.Allow the heat exchanger to thoroughly dry.
10.Remove the field supplied rear refractory cover from the back of the combustion chamber of the heat exchanger and reassemble.
11.Close isolation valves on piping to isolate boiler from system. Attach a hose to the boiler drain and flush boiler thoroughly with clean water by using purging valves to allow water to flow through the water
12.Perform
13.Replace the access cover and restore boiler to operation.
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