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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 52. 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  readings  exceed  the  maximum 
shown in TABLE 22, 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.
TABLE 22 
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
FIGURE 52