Polarization And Phasing - Amana GUCA045AX30 Service Instructions Manual

As more and more electronic's are introduced to the Heat-
ing Trade, Polarization of incoming power and phasing
of primary to secondary voltage on transformers becomes
more important.
Polarization has been apparent in the Appliance industry
since the introduction of the three prong plug, however,
the Heating Industry does not use a plug for incoming
power, but is hard wired.
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 re-
quire phasing between the primary and secondary sides
of step-down transformers.
To instill new working habits for our trade, we recom-
mend that these two items be checked during normal
installation and/or service calls. See as follows:
CHECKING FOR PHASING - PRIMARY TO SECONDARY OF UNMARKED TRANSFORMERS*
Meter Reads
24 Volts
VO LT / O H M
M E TE 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.
*Note: For flame rectification the common side of the secondary voltage (24 V) is cabinet grounded. If you were to bench
test a transformer the primary neutral and secondary common must be connected together for testing purposes.
C
24 V
R
52
Rev. 0

POLARIZATION AND PHASING

Line Voltage
Transformer
(Neutral)
C
R
Line Voltage
L1 (Hot)
VO LT / O H M
M E TE R
Neutral
120 V
L1
Phasing Symbol
Incoming Power
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
Meter Reads
120 Volts
R
VO LT / O H M
M E TE R
Reads 96 Volts - In Phase
C
R
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.
Checking for polarization and phasing should become a
habit in servicing. Let's start now.
Note: The new White-Rodgers 50A55-288 and the
Heatcraft HSI-2 integrated ignition controls used on the
GUCA and GCCA model furnaces, have a diagnostic flash
code for reversed polarity. This is a six flash diagnostic
flash code (Refer to Troubleshooting-Diagnostic Chart on
pages 50 and 51).
Meter Reads
0 Volts
Volt / Ohm
Meter
This is the Common
or Neutral Leg
N
L1
VO LT / O H M
M E TE R
N
L1
VO LT / O H M
M E TE R