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I- Proper Ground and Voltage
Furnace  must  be  properly  grounded  for  proper  perfor-
mance. 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 gure 
53.  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  26,  make  repairs  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 gure 54. This voltage should be in the range 
of 97 to 132 Vac.
TABLE 25 
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
FIGURE 54