Proper Ground and Voltage
CAUTION
Electric Shock Hazard. Can cause injury or
death. Unit must be properly grounded in
accordance with national and local codes.
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 52. A wide
variation in the voltage between Line Neutral and "C"
CHECK VOLTAGE BETWEEN LINE NEUTRAL
AND LOW VOLTAGE "C" TERMINAL
Red LED
Recall
as a function of load indicates a poor or partial ground.
Compare the readings to Table 19. If the readings
exceed the maximum shown in Table 19, 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 52. This voltage should be in the range of 97
to 132 VAC
Furnace Status
Power On Furnace Idle
CAI / Ignitor Enerigized
Indoor Blower Energized
CHECK VOLTAGE BETWEEN LINE HOT
AND LINE NEUTRAL
Red LED
Recall
Figure 52.
Page 46
Measurement VAC
Expected
Maximum
0.3
0.75
Less than 2
10
Table 19.
2
5
31-5000729 Rev. 0