Page 40
Cleaning the Heat Exchanger and Burners
NOTE − Use papers or protective covering in front of the fur-
nace during cleaning.
1 − Turn off both electrical and gas power supplies to fur-
nace.
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, prima-
ry limit switch and make−up box then disconnect them.
4 − Remove the screws that secure the combustion air in-
ducer/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 combus-
tion air inducer. Be careful with the collector box gas-
ket. If the gasket is damaged, it must be replaced to
prevent leakage.
6 − Disconnect gas supply piping. Remove the screw se-
curing the burner box cover and remove cover. Re-
move the four screws securing the burner manifold as-
sembly to the vestibule panel and remove the
assembly from the unit.
7 − Remove screws securing burner box and remove
burner box.
8 −
NOX units only
− Remove screw securing NOX insert.
Remove NOX insert. See figure 37.
EL280UH BURNER, COMBUSTION AIR INDUCER ASSEMBLY &
HEAT EXCHANGER REMOVAL
FIGURE 36
Heat Exchanger
Manifold And Gas Valve
Retention Rings
Cross Over
Ignitor
Sensor
Rollout Switches
(location)
gasket
collector box
orifice plate
flue transition
pressure switch
combustion air inducer