Lennox EL196UH030XE24B Information page 11

Rollout Switch(s)
Flame Sensor
Burner Box Front
B-Heating Components
Combustion air inducer (B6), primary limit control (S10), ig­
nitor, burners, flame rollout switch (S47), gas valve (GV1),
combustion air pressure switch (S18), and heat exchangers
are located in the heating compartment. The heating
compartment can be accessed by removing the outer ac­
cess panel.
1. Flame Rollout Switches (Figure 6)
Flame rollout switches S47 are SPST N.C. high temperature
limits located on the left and right of the front buner box plate.
S47 is wired to the burner ignition control A92. When ei­
ther of the switches sense flame rollout (indicating a
blockage in the combustion passages), the flame rollout
switch trips, and the ignition control immediately closes
the gas valve. Switch S47 in all EL196UHE units is factory
preset to open at 210_F + 12_F (99_C + 6.7_C) on a tem­
perature rise. All flame rollout switches are manual reset. See
table 4 flash code 8 for troubleshooting.
EL196UHE Burner Box Assembly
Gas Valve
FIGURE 6
2. Heat Exchanger (Figure 7)
EL196UHE units use an aluminized steel primary and
stainless steel secondary heat exchanger assembly.
Heat is transferred to the air stream from all surfaces of
the heat exchanger. The shape of the heat exchanger en­
sures maximum efficiency.
The combustion air inducer pulls fresh air through the burn­
er box. This air is mixed with gas in the burners. The gas /
air mixture is then burned at the entrance of each clam­
shell. Combustion gases are then pulled through the primary
and secondary heat exchangers and exhausted out the ex­
haust vent pipe.
3. Primary Limit Control (Figure 7)
Primary limit (S10) used on EL196UHE units is located in the
heating vestibule panel. When excess heat is sensed in the
heat exchanger, the limit will open. Once the limit opens, the
furnace control energizes the supply air blower and de-en­
ergizes the gas valve. The limit automatically resets when
unit temperature returns to normal. The switch is factory
set and cannot be adjusted. For limit replacement remove
wires from limit terminals, remove mounting screws, rotate
limit switch 90 degrees and slowly remove from the vesti­
bule panel. Install replacement limit with same care. See
table 4 flash code 7 for troubleshooting if limit switch
opens during operation.
Page 11
Burner Assembly
Ignitor