Lennox ML193DFE Series Unit Information page 17

C-Blower Compartment
IMPORTANT
Each blower is statically and dynamically balanced
as an assembly before installation in the unit.
EL196DFE units are equipped with a constant torque ECM
motor. It has a DC motor coupled to an electronic control
module both contained in the same motor housing. The
motor is programmed to provide constant torque at each
of the five selectable speed taps. Each tap requires 24
volts to energize.
Input Voltage Requirements
The circuit is designed to be operated with AC voltage. To
enable a tap requires 12 to 33VAC. Expected current draw
will be less than 20mA.
Troubleshooting the Motor
Troubleshooting the motor is an easy process. Follow
steps below.
1 - Shut off power to unit.
2 - Remove input plugs P48 and P49 from motor. See
FIGURE 17 for troubleshooting procedure.
Note - FIGURE 17 is a typical ignition control illustration.
If correct voltage is present in tests 1 and 2 and motor
is not operating properly, replace motor. The motor is not
field repairable.
If replacing the indoor blower motor or blower wheel is
necessary, placement is critical. The blower wheel must
be centered in the blower housing as shown in FIGURE
14. When replacing the indoor blower motor the set screw
must be aligned and tightened with the motor shaft as
shown in FIGURE 15.
Secondary Limit Controls
The secondary limit is located in the blower compartment
on the back side of the blower housing. See FIGURE 16.
When excess heat is sensed in the blower compartment,
the limit will open. If the limit is open, the furnace control
energizes the supply air blower and closes the gas valve.
The limit automatically resets when unit temperature re-
turns to normal. The secondary limit cannot be adjusted.
BLOWER WHEEL REPLACEMENT
ALIGN AND TIGHTEN SET SCREW WITH
FLAT SIDE OF MOTOR SHAFT
Housing Hub
Motor
Shaft
SECONDARY LIMIT CONTROL
Blower Assembly
Page 17
Center Blower Wheel
in Blower Housing
FIGURE 14
Set Screw
FIGURE 15
Secondary Limit
FIGURE 16