Maintenance - Lennox EL180UHE Series Manual

VI-MAINTENANCE
A-Preliminary and Seasonal Checks
1 - Inspect electrical wiring, both field and factory installed
for loose connections. Tighten as required.
2 - Check voltage at disconnect switch. Voltage must be
within range listed on the nameplate. If not, consult the
power company and have voltage condition corrected
before starting unit.
At the beginning of each heating season, the system
should be checked as follows:
B-Filters
Filters should be inspected monthly. Clean or replace the
filters when necessary to ensure that the furnace operates
properly. Replacement filters must be rated for high veloc­
ity airflow. See table 14.
IMPORTANT
If a high­efficiency filter is being installed as part of
this system to ensure better indoor air quality, the fil­
ter must be properly sized. High­efficiency filters
have a higher static pressure drop than standard­ef­
ficiency glass/foam filters. If the pressure drop is too
great, system capacity and performance may be re­
duced. The pressure drop may also cause the limit to
trip more frequently during the winter and the indoor
coil to freeze in the summer, resulting in an increase
in the number of service calls.
Before using any filter with this system, check the
specifications provided by the filter manufacturer
against the data given in the appropriate Lennox
Product Specifications bulletin. Additional informa­
tion is provided in Service and Application Note
ACC­00­2 (August 2000).
TABLE 14
Furnace
Cabinet Width
Side Return
A - 14-1/2" 16 X 25 X 1 (1)
B - 17-1/2" 16 X 25 X 1 (1)
C - 21" 16 X 25 X 1 (1)
D - 24-1/2" 16 X 25 X 1 (2)
Filter Size
Bottom Return
14 X 25 X 1 (1)
16 X 25 X 1 (1)
20 X 25 X 1 (1)
24 X 25 X 1 (1)
Page 25
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 four screws
securing the burner manifold assembly to the vestibule
panel and remove the assembly from the unit.
7 - NOX units only - Remove screw securing NOX insert.
Remove NOX insert. See figure 26.
8 - Remove screws from both sides, top and bottom of
vestibule panel.
9 - 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 27.
10 -Backwash using steam. Begin from the burner opening
on each clam. Steam must not exceed 275°F.
11 -To clean burners, run a vacuum cleaner with a soft
brush attachment over the face of burners. Visually in­
spect inside the burners and crossovers for any block­
age caused by foreign matter. Remove any blockage.
Figure 25 shows burner detail.
12 -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.
13 -Reinstall heat exchanger in vestibule. (Replace the
five screws in the cabinet from step 10 if removed).
14 -NOx units only - Replace NOx inserts.
15 -Reinstall collector box and combustion air assembly.
Reinstall all screws to the collector box and combus­
tion air inducer. Failure to replace all screws may
cause leaks. Inspect gaskets for any damage and re­
place if necessary.