Weil-McLain NX Warning-Checkfor Excess Fuel Accumulation, Burner Cover, Cover Installation, Page

!Warning–Check for Excess Fuel Accumulation.

Do not attempt to start the burner when excess fuel or vapor has accumulated in the appliance. Starting the burner under these conditions could result in a puffback of hot combustion gases, high smoke levels, or otherwise hazardous operation.

Could cause death, personal

injury and/or substantial property damage due to equipment malfunction, heavy smoke, soot blockage, hot gas puff-back, fire and asphyxiation hazard.

S112

•Set Combustion with Test Instruments

1.Allow the burner to run for approximately 5 to 10 minutes.

2.Set the stack draft between -0.01” to -0.02” w.c. for chimney vent applications. No

draft adjustment required for direct venting.

3.Follow these five steps to properly adjust the burner:

Step 1: Adjust the head/air until a trace of smoke is achieved. This can be accomplished by turn- ing the screw on the head/air adjustment plate assembly to increase air (CCW) or decrease air (CW).

Step 2: At the trace of smoke level, measure the CO2 (or O2) . This is the vital reference point for further adjustments. Example: 13.5% CO2 (2.6% O2)

Step 3: Increase the air to reduce the CO2 by 1.5 to 2 percentage points. (O2 will be increased by approximately 2.0 to 2.7 percentage points.) Ex- ample: Reduce CO2 from 13.5% to 11.5% (2.6% to 5.3% O2).

Step 4: Recheck smoke level. It should be Zero.

•This procedure provides a margin of reserve air to accommodate variable conditions.

•If the draft level has changed, recheck the smoke and CO2 levels and readjust burner, if necessary.

Step 5: Once the combustion has been set, tight- en the lower acorn nut and splined nut on the air adjustment assembly. See Figure 5.

Start the Burner

4.Chimney Vent Systems: Install the burner cover and repeat Steps 2 and 4 above. If CO2 increas- es (O2 decreases), remove the cover and adjust the air setting so the CO2 (O2) with the cover installed meets the requirements of Step 3.

5.Direct Vent Systems with Outside Air Ducted to Burner: Install the burner cover.

6.Start and stop the burner several times to ensure satisfactory operation. Test the primary control and all other appliance safety controls to verify that they function according to the manufactur- er’s specifications.

•Cover Installation

1.Install the cover mounting screws in the cover mounting plate.

2.Install the cover over the mounting plate while aligning the side slots with the installed cover mounting screws.

3.Direct Vent specified burners include an opening on the top of the cover for an outside air intake.

Figure 6. – Burner Cover

SK9804A

WM 550-141-996/1105 RWB 6104WMNX R1005

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