Servicing - Intertek ACVC96 Service Instructions Manual

SERVICING

Some of the electronic boards being used today, with flame
rectification, will not function properly and/or at all without
polarization of incoming power. Some also require phasing
between the primary and secondary sides of step-down
transformers.
CHECKING FOR PHASING - PRIMARY TO SECONDARY OF UNMARKED TRANSFORMERS*
METER READS
24 VOLTS
. .
. .
. .
V O L T / O H M
M E TE R
C
R
If meter reads approximately 96 volts - the primary to secondary are in phase - if reads approximately 144 volts out of phase
- reverse low voltage wires.
C
24 V
R
METER READS
LINE VOLTAGE
TRANSFORMER
(NEUTRAL)
LINE VOLTAGE
L1 (HOT)
VO L T / O HM
M E TE R
NEUTRAL
120 V
L1
PHASING SYMBOL
METER READS
120 VOLTS
VOLT / OHM
METER
THIS IS L1 OR THE
HOT POWER LEG
These then should be wired to the furnace accordingly.
C
120 VOLTS
R
V O L T / O H M
M E TE R
READS 96 VOLTS - IN PHASE
C
READS 144 VOLTS - OUT OF PHASE
Some transformers will display phasing symbols as shown
in the illustration to the left to assist in determining proper
transformer phasing.
INCOMING POWER
METER READS
0 VOLTS
VOLT / OHM
METER
THIS IS THE COMMON
N
L1
V O L T / O H M
M E TE R
N
R L1
VO L T / O HM
M E TE R
OR NEUTRAL LEG
57