508189-01
Issue 2116
Page 25 of 42
Proper Ground and Voltage
Furnace must be properly grounded for proper
performance. 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 Table 14. If the readings
exceed the maximum shown in Table 14, 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 15. This voltage should be in the
range of 97 to 132 Vac.
Furnace Status
Measurement VAC
Expected
Maximum
Power On Furnace Idle
0.3
2
CAI / Ignitor Enerigized
0.75
5
Indoor Blower Energized
Less than 2
10
Table 14.
CHECK VOLTAGE BETWEEN LINE NEUTRAL
AND LOW VOLTAGE “C” TERMINAL
CHECK VOLTAGE BETWEEN LINE HOT
AND LINE NEUTRAL
Figure 15.