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Cleaning the Heat Exchanger and Burners
NOTE: Use papers or protective covering in front of the
furnace during cleaning.
1.
Turn off both electrical and gas power supplies to
furnace.
2.
Remove flue pipe and top cap (some applications top
cap can remain) from the unit.
3.
Label the wires from gas valve, rollout switches,
primary limit switch and make-up box then disconnect
them.
4.
Remove the screws that secure the combustion air
inducer/pressure switch assembly to the collector box.
Carefully remove the combustion air inducer to avoid
damaging blower gasket. If gasket is damaged, it must
be replaced to prevent leakage.
5.
Remove the collector box located behind the
combustion air inducer. Be careful with the collector
box gasket. If the gasket is damaged, it must be
replaced to prevent leakage.
6.
Disconnect gas supply piping. Remove the screw
securing the burner box cover and remove cover.
Remove the four screws securing the burner manifold
assembly to the vestibule panel and remove the
assembly from the unit.
Figure 30. Burner, Combustion Air Inducer Assembly & Heat Exchanger Removal
Page 32 of 34
7.
Remove screws securing burner box and remove
burner box.
8.
NOx units only - Remove screw securing NOx insert.
Remove NOx insert. See Figure 31.
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 32.
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 inside the burners and crossovers for any
blockage caused by foreign matter. Remove any
blockage. Figure 30 shows burner detail.
13. To clean the combustion air inducer visually inspect
and using a wire brush clean where necessary. Use
compressed 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.
Issue 1809
507327-01
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