Page 41
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 38.
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
36 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.
EL280UH NOx INSERTS
FIGURE 37
NOx Insert
FIGURE 38
Remove 5 screws if necessary
(either side of cabinet)
1
2
3
4
5
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.
