Amana AMVM97 Service Instructions Manual page 47

OPERATION
High Pressure Switch Operation
• High Pressure Switch action is used to determine the
inducer speed required to achieve the 100% firing rate
of the appliance. The determination is made by the
IFC during the calibration process.
• The HPS must remain closed during 100% fire opera-
tion. If it opens during 100% fire operation, the IFC
will increase the inducer speed at a rate of 1% per sec
in an attempt to re-close the pressure switch up to
the maximum allowed RPM. If the HPS is re-closed
successfully, the IFC will complete the Heat mode and
perform the Calibration routine on the next call for
heat. If the HPS remains open, the IFC will end the
Heat mode through the Post-purge and perform the
Calibration routine immediately (error code "E9" is
flashed until calibration routine is successful).
• High Pressure Switch check takes place during the
Calibration routine. If the switch is stuck open or
closed calibration will not be completed and the ap-
propriate error code will be logged and displayed.
Hot Surface Igniter Operation
The IFC energizes a relay to control the line voltage Hot
Surface Igniter. The HSI warm up time will be fixed for all
ignition trials. Both the continuity of the igniter and the
ability of the relay to energize the igniter are continuously
monitored during the Igniter Warm-up and Ignition Activa-
tion Periods.
ECM Motor
An Emerson® UltraTech® four wire indoor fan motor pro-
vides supply air to the conditioned space. This is the same
motor used on Goodman & Amana previous generation com-
municating furnaces.
The ECM motor consists of two sections;
1. A motor body containing 3 phase motor windings
2. An electronic control module (end bell).
In the event of a non-operating motor; the following items
should be checked. There are two harnesses which connect
the blower motor to the IFC. The line voltage (5 Pin) har-
ness provides 115 volts directly off of the IFC L1 and neu-
tral terminals on ½ hp ECM motors. On furnaces with ¾ and
1 HP ECM motors, L1 is fed to the motor through an induc-
tor coil. The inductor coil conditions the power supply to
the motor smoothing out spikes and electrical noise. The
low voltage harness is a 4 wire harness that supplies 12
volts DC to terminals 1 & 4 of the motor and communicat-
ing signals on terminals 3 & 4.
T
HE CONTROL MODULE CONTAINS COMPONENTS WHICH CAN HOLD AN
ELECTRICAL CHARGE FOR SEVERAL MINUTES
,
TAKEN APART IT MUST BE ALLOWED TO DISSIPATE VOLTAGE BY
WAITING FIVE MINUTES BEFORE IT IS INSPECTED INTERNALLY
BELL CAN BE SEPARATED FROM THE MOTOR BODY BY REMOVING THE
THREE SCREWS WHICH JOIN THEM
THE INTERANL HARNESS CAN BE SEPARATED
AND MOTOR CAN THEN BE INSPECTED SEPARATELY
The motor contains three windings of equal resistance + /
- 10%. Resistance between windings is generally less than
10 ohms and will vary between models. To take this read-
ing; the ohm meter leads are placed in the wiring harness,
previously disconnected from the internal control unit con-
nector.
Inspect capacitors inside the control unit for bulging or swol-
len caps. The end bell should be replaced if components
appear swollen or bulging. A functioning control unit should
have a phase to phase resistance of greater than 100K be-
tween any two pins. A separated control unit is shown be-
low. To take this reading; the ohm meter leads are placed
in the end bell socket and not in the wiring harness.
Beyond basic visual checks and voltage / resistance checks;
the Emerson ECM motor may be tested with an Emerson
UltraCheck-EZ™ diagnostic tool (Goodman Part UTT-01).
This tool will test the motor windings and also the commu-
nicating module of the motor.
WARNING
. B
EFORE THE MOTOR IS
. T
. O
NCE THE SCREWS ARE REMOVED
. T
HE CONTROL MODULE
.
3 Wire
Motor-to-Control Harness
3 Pin Connector
Motor
Connector
HE END
,
47