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H- Proper Ground and Voltage
A poorly grounded furnace can contribute to premature ig
nitor 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 15. 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 the table below. If the read
ings exceed the maximum shown in table 11, make re
pairs before operating the furnace.
2 - In addition, measure the AC voltage from Line Hot to
Line Neutral (spade terminals) on the integrated con
trol. See figure 16. This voltage should be in the range
of 204 to 264VAC.
TABLE 11
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
AN2
GREEN
AN1
RED
CHECK VOLTAGE BETWEEN LINE NEUTRAL
AND LOW VOLTAGE “C” TERMINAL
FIGURE 15
FIGURE 16
AN2
GREEN
AN1
RED
CHECK VOLTAGE BETWEEN LINE HOT
AND LINE NEUTRAL
