System Operation - Intertek ACVC96 Service Instructions Manual

SYSTEM OPERATION

22. Motor Parameters. This condition occurs if the motor
does not receive all the information is requires to operate
or an event occurs that prevents the motor from running,
or the motor fails to start for (40) consecutive attempts.
The diagnostic error code for the this condition is b7.
Probable causes are intermittent wiring connection be-
tween the control and motor, an error with the furnace
control, or any of the conditions described in 19, 20, or
21 above.
23. Low Indoor Airflow. This condition occurs if the indoor
airflow falls below a calculated minimum value. The mini-
mum airflow value is calculated from factors defined in
44
the shared data set. If the airflow falls below the calcu-
lated minimum, the furnace will continue to operate with
the reduce airflow. If the furnace was operating at high
stage, it will stage back to low in an effort to remedy the
condition. The furnace will halt operation if the airflow
falls to 0 CFM.
The diagnostic error code for the this condition is b9.
Probable causes are blocked/clogged filters, blocked
or restrictive ductwork, or undersized ductwork.