9 − Remove screws from both sides, top and bottom of vestibule panel.
10 −Remove heat exchanger. It may be necessary to spread cabinet side to allow more room. If so, remove five screws from the left side or right side of cabinet. See figure 39.
11 − Backwash using steam. Begin from the burner opening on each clam. Steam must not exceed 275°F.
12−To clean burners, run a vacuum cleaner with a soft brush attachment over the face of burners. Visually inspect in- side the burners and crossovers for any blockage caused by foreign matter. Remove any blockage. Figure 37 shows burner detail.
13−To clean the combustion air inducer visually inspect and using a wire brush clean where necessary. Use com- pressed air to clean off debris and any rust.
14−Reinstall heat exchanger in vestibule. (Replace the five screws in the cabinet from step 10 if removed).
15−NOx units only − Replace NOx inserts.
16−Reinstall collector box and combustion air assembly. Reinstall all screws to the collector box and combustion air inducer. Failure to replace all screws may cause leaks. Inspect gaskets for any damage and replace if necessary.
17−Reinstall burner box, manifold assembly and burner box cover.
ML180UH NOx INSERTS |
NOx Insert |
FIGURE 38
Remove 5 screws if necessary |
(either side of cabinet) |
1 |
2 |
3 |
4 |
5 |
FIGURE 39
18−Reconnect all wires.
19−Reconnect top cap and vent pipe to combustion air in- ducer outlet.
20−Reconnect gas supply piping.
21−Turn on power and gas supply to unit.
22−Set thermostat and check for proper operation.
23−Check all piping connections, factory and field, for gas leaks. Use a leak detecting solution or other preferred means.
CAUTION
Some soaps used for leak detection are corrosive to certain metals. Carefully rinse piping thoroughly af- ter leak test has been completed. Do not use matches, candles, flame or other sources of ignition to check for gas leaks.
24 −If a leak is detected, shut gas and electricity off and repair leak.
25 −Repeat steps 24 and 26 until no leaks are detected.
26 −Replace access panel.
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