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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 55. A wide vari-
ation in the voltage between Line Neutral and “C” as
a function of load indicates a poor or partial ground.
Compare the readings to the table below. If the read-
ings exceed the maximum shown in TABLE 33, make
repairs before operating the furnace.
2 - In addition, measure the AC voltage from Line Hot
to Line Neutral (spade terminals) on the integrated
control. See FIGURE 55. This voltage should be in
the range of 97 to 132 Vac.
TABLE 33
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 55
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