Page 35
A-Heat Exchanger and Burner FIGURE 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, thermal switch,
primary limit switch and make-up box then
disconnect them.
4 -
Remove the screws that secure the combustion air
inducer to the collector box.
5 - Disconnect gas supply piping. Remove the screw
securing the air fuel plenum and remove along with
the air inake assembly as one component.
6 - Remove screws from both sides, top and bottom of
vestibule panel.
7 -
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 24.
8 -
Back wash using steam. Begin from the burner
opening on each tube. Steam must not exceed
275°F.
9 -
To clean burner, remove from the air gas plenum
and run a vacuum cleaner over the face of burner.
Visually inspect inside the burner for any blockage
caused by foreign matter. Remove any blockage.
FIGURE 25 shows burner detail.
Replace gasket
between burner plate and air fuel plenum then
re-install burner plate.
10 - 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.
11 - Reinstall heat exchanger in vestibule. (Replace the
five screws in the cabinet from step 7 if removed).
12 -
Reinstall the flue pipe, top cap, flue chase and
internal flue pipe assembly from the uni
13 -
Reconnect all wires.
14 -
Reconnect gas supply piping.
15 - Turn on power and gas supply to unit.
16 - Set thermostat and check for proper operation.
17 - 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
after leak test has been completed. Do not use
matches, candles, flame or other sources of ignition
to check for gas leaks.
18 -
If a leak is detected, shut gas and electricity off
andrepair leak.
19 - Repeat steps 21 and 23 until no leaks are detected.
20 - Replace access panel.
Remove five screws if necessary
(either side of cabinet)
1
2
3
4
5
FIGURE 24
