Page 25
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, top cap, flue chase and internal
flue pipe assembly 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 four
screws securing the burner manifold assembly to
the vestibule panel and remove the assembly from
the unit.
7 - Remove screws from both sides, top and bottom of
vestibule panel.
8 -
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 25.
9 - Back wash using steam. Begin from the burner
opening on each clam. Steam must not exceed
275°F.
10 -
To clean burners, run a vacuum cleaner with a soft
brush attachment over the face of burners. Visually
inspect insid he burners and crossovers for any
blockage caused by foreign matter. Remove any
blockage. Figure 24 shows burner detail.
BURNER, COMBUSTION AIR INDUCER ASSEMBLY &
HEAT EXCHANGER REMOVAL
heat exchanger
gasket
collector box
orifice plate
internal flue pipe
pressure switch
combustion air inducer
burners
manifold and gas valve
retention rings
cross over
heat exchanger
gasket
collector box
orifice plate
internal flue pipe
pressure switch
combustion air inducer
burners
manifold and gas valve
flue chase
gasket
ignitor
rollout switch
sensor
FIGURE 24
