Lennox EL297UH090XV60C - I- Proper Ground and Voltage

Page 82
I- Proper Ground and Voltage
A poorly grounded furnace can contribute to premature
ignitor failure. Use the following procedure to check for
ground and voltage to the integrated control.
1 - Measure the AC voltage between Line Neutral
(spade terminals) and “C” terminal (low voltage
terminal block) on the integrated control. See
FIGURE 54. A wide variation in the voltage between
Line Neutral and “C” as a function of load indicates
a poor or partial ground. Compare the readings to
TABLE 30. If the readings exceed the maximum
shown in table 1, make repairs before operating the
furnace.
NOTE - FIGURE 54 is a typical ignition illustration.
Use as reference.
2 - In addition, measure the AC voltage from Line Hot
to Line Neutral (spade terminals) on the integrated
control. See FIGURE 54. This voltage should be in
the range of 97 to 132 Vac.
TABLE 30
Furnace Status
Measurement VAC
Expected Maximum
Power On Furnace Idle 0.3 2
CAI / Ignitor Energized 0.75 5
Indoor Blower Energized Less than 2 10
CHECK VOLTAGE BETWEEN LINE NEUTRAL
AND LOW VOLTAGE “C” TERMINAL
CHECK VOLTAGE BETWEEN LINE HOT
AND LINE NEUTRAL
W1 W2 G
Y2
Y1
CC
RDHL ODS
W1 W2 G
Y2
Y1
CC
RDHL ODS
FIGURE 54