Lennox EL296DFV Series Unit Information page 33

Troubleshooting Motor Windings
Ensure that motor windings are not damaged by perform-
ing the following tests:
NOTE - If your ohm meter is not an auto-ranging type, set
it to the highest ohm scale (100k ohms or greater) before
performing tests.
TABLE 14
Ohm Meter Range
Scale Measurement Range
in words
2M two megohm -- two
million ohms
200K two hundred kilohm --
two hundred thousand
ohms
20K twenty kilohm -- twenty
thousand ohms
2K two kilohm -- two thou-
sand ohms
200 two hundred ohm
FIGURE 11
TEST A
Measure the resistance between each of the three motor
leads (3-pin plug) and the unpainted part of the end shield.
If the winding resistance to ground is <100k ohms, re-
place the motor and control module. If the resistance
to ground is >100k, the motor windings are fine. Pro-
ceed to Test B.
Test A
FIGURE 12
TEST B
Use an ohmmeter to measure the motor phase-to-phase
resistance by checking these combinations of the 3-pin
motor plug. For the purpose of this test, start at either end
of the connector as lead 1.
1 - The lead-to-lead resistance across any two leads
2 - Each lead-to-lead resistance should be the same.
If the measured resistance is greater than 20 ohms, re-
place the motor and control module.
ohms
0-2,000,000
0-200,000
0-20,000
0-2,000
0-200
C- Heating Components
1. Ignitor
The SureLight
Ignitor longevity is enhanced by controlling voltage to the
ignitor. The integrated control provides a regulated 120
volts to the ignitor for a consistent ignition and long ignitor
life. Ohm value should be 39 to 70. See FIGURE 14 for
ignitor location and FIGURE 15 for ignitor check out.
NOTE - The EL296DFV(X) furnace contains electronic
components that are polarity sensitive. Make sure that the
furnace is wired correctly and is properly grounded.
2. Flame Sensor
A flame sensor is located on the left side of the burner
support. See FIGURE 14. The sensor tip protrudes into
the flame envelope of the left-most burner. The sensor
can be removed for service without removing any part of
the burners. During operation, flame is sensed by current
passed through the flame and sensing electrode. The
SureLight control allows the gas valve to remain open as
long as flame signal is sensed. To check flame sense sig-
nal use the push-button found on the integrated control
and go to Field Test Mode. The menu will display the flame
signal. See TABLE 15 for flame signal.
Page 33
should be less than 20 ohms.
Test B
FIGURE 13
ignitor is made of durable silicon nitride.
®
TABLE 15
Flame Signal in Microamps
Normal Low
2.6 or greater 2.5 or less
Drop Out
1.1