Intertek ACVC96 Service Instructions Manual page 43

SYSTEM OPERATION
NOTE: Turn off power to the furnace prior to inserting memory
card onto the control. With memory card inserted onto con-
trol, turn power to furnace on. Control has accepted memory
card data once control displays ON on the dual, 7-segment
display. Memory card may be left on control or removed
and used on another furnace of the same model. Turn power
off to furnace prior to removing memory card.
15. ECM Blower Motor Not Running. This condition oc-
curs if the control fails to detect the ECM blower motor
running when it should be running. The furnace will not
operate if the control detects the blower motor is not
running when it should be running. The diagnostic error
code for this condition is b0. The probable cause loose
or disconnected wiring between the motor and control,
an open inductor (3/4 Hp and 1 Hp motors only), or a
failed ECM blower motor (see section S-16C in Servic-
ing).
16. ECM Motor Communciations Lost. This condition oc-
curs if the furnace control cannot communicate with the
ECM blower motor. The furnace will not operate if the
control cannot communicate with the blower motor. The
diagnostic error code for this condition is b1. The prob-
able cause loose or disconnected wiring between the
motor and control, a failed ECM blower motor (see sec-
tion S-16C in Servicing), or a failed control.
17. Motor Horsepower Mismatch. This condition occurs
if the horsepower of the motor connected to the control
does not match the motor horsepower specified in the
shared data set. The furnace will not operate is there is
a motor horsepower mismatch. The diagnostic error
code for this condition is b2.
Verify that the installed motor is the correct motor for
the furnace model. Obtain the correct motor for the fur-
nace model. Verify the shared data set is correct for the
furnace. The shared data set may be corrected using
the appropriate memory card. Contact your distributor
for the correct memory card. See 13 and 14 above for
additional memory card information.
18. ECM Motor Operating in a Limiting Condition. This
condition will occur if the ECM operates in a power,
speed, or temperature limiting condition. The furnace
will continue operating at reduced performance. The di-
agnostic error code for the this condition is b3.
Power Limit. In attempting to deliver the airflow demand,
the motor may exceed its rated output power. The mo-
tor will reduce its output to prevent exceeding its power
limit. This will result in lower than demanded airflow.
This will occur under high loading conditions. High load-
ing conditions could be due to blocked/clogged filters,
blocked or restrictive ductwork, or undersized ductwork.
Speed Limit. In attempting to deliver the airflow demand,
the motor may exceed its maximum speed of 1500 RPM.
The motor will reduce its speed to prevent exceeding its
maximum. This will result in lower than demanded air-
flow. A blocked inlet, lightly loaded or no load condi-
tions could cause high motor speeds.
Temperature Limit. In attempting to deliver the airflow
demand, the motor may exceed its temperature limit.
The motor will reduce its output in an attempt to reduce
its temperature. This will result in lower than demanded
airflow. A high ambient temperatue at a high loading
condition is the most probable cause. Reduce the am-
bient temperature and/or motor loading/demand.
19. Motor Trips. This condition occurs if the ECM motor
senses a loss of control or becomes overloaded. The
furnace may halt operation if the motor shuts down for a
trip condition. The diagnostic error code for this condi-
tion is b4.
Loss of Control (Lost Rotor Trip). This occurs if a sud-
den change in speed or torque is detected. The motor
will shut down and restart if this condition is encoun-
tered. Possible causes are abnormal loading conditions
due to sudden blockages of the duct system or sudden
high increases in the loading on the motor.
Overload (Current Trip). This occurs if the motor be-
comes overloaded due to high loading conditions. The
motor will shut down and restart if this condition is en-
countered. High loading conditions could be due to
blocked/clogged filters, blocked or restrictive ductwork,
or undersized ductwork.
20. Motor Locked Rotor. This condition occurs if the mo-
tor fails to start after (10) consecutive attempts. The
furnace will not operate if the ECM blower motor fails to
start. The diagnostic error code for this condition is b5.
The probable cause is an obstruction in the blower hous-
ing or wheel, siezed motor bearings, or a failed blower
motor.
21. Motor Volts. This condition occurs if the line voltage is
too low or too high, or if the motors power module gets
too hot. The ECM motor will shut down while the abnor-
mal condition is present. If the abnormal condition is
cleared, the motor will restart. The furnace will be inop-
erable while the motor is off.
Over Voltage. If the line voltage exceeds 140VAC, the
motor will shut down due to an over voltage condition.
Verify the line voltage to the furnace is within the range
specified on the rating plate.
Under Voltage. If the line voltage is less than 70VAC,
the motor will shut down due to an under voltage condi-
tion. Verify the line voltage to the furnace is within the
range specified on the rating plate.
Over Temperature. A high ambient temperatue or a high
loading condition is the most probable cause. Reduce
the ambient temperature and/or motor loading/demand.
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