Lochinvar 400-801 Check flame signal, Review with owner, Cleaning boiler heat exchanger

2 Maintenance (continued)

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.

Review with owner

1.Review the Knight XL User’s Information Manual with the owner.

2.Emphasize the need to perform the maintenance schedule specified in the Knight XL 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 start-up at the beginning of the next heating season.

Cleaning boiler heat exchanger

For recommended materials; including brush, appropriate extension(s), refractory cover, and detailed instructions see Table 2-2 - Heat Exchanger Cleaning Kits.

1.Shut down boiler:

•Follow the “To Turn Off Gas to Appliance” instructions for the boiler in Section 10 - Startup of the Installation and Operation Manual.

•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 on page 3 of this 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.

Service Manual

7.Brush the heat exchanger while dry using a nylon bristle brush. Caution: DO NOT use a metal brush. Re-vacuum the heat exchanger.

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 make-up line to the boiler.

12.Perform start-up and check-out procedures in the Check Flame and Combustion - Section 10 - Startup of the Installation and Operation Manual.

13.Replace the access cover and restore boiler to operation.

Table 2-2Heat Exchanger Cleaning Kits

Model	Kit	Part	Component
	Number	Number	Description
		CTN20005	Rear Refractory Cover
400	KIT30063	MSC20083*	Nylon 4" Wheel Brush*
		MSC20084	3mm Allen Wrench
		MSC20086	1/4" x 24" Drill Extension
		CTN20005	Rear Refractory Cover
501 - 801	KIT30064	MSC20083*	Nylon 4" Wheel Brush*
		MSC20085	1/4" x 12" Drill Extension
		MSC20086	1/4" x 24" Drill Extension

CAUTION * Do NOT use a metal brush. Only use the kit provided brush or an equivalent

replacement nylon brush.

Figure 2-5Rope Gasket - Heat Exchanger Door

ROPE GASKET

CAUTION: IF GASKET IS DAMAGED

DO NOT REUSE, THE HEAT EXCHANGER DOOR

MUST BE REPLACED.

Rope gasket is intended for sealing combustion NOTICE (FIG. 2-5). If damaged DO NOT reuse, the

heat exchanger door must be replaced. Consult factory for replacement heat exchanger door (kit WTR3080 and WTR3086).

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