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Diagnostics
2. OVERSPEED OPERATION (CODE “66”)
Note: This code will only be displayed during the first
three minutes of blower operation and then only if
the call for fan is great enough to force the motor into
speed limit.
A. Is the duct work of the system restrictive or con-
fined? Or, maybe many (or all) of the supply reg-
isters are closed in the duct system. If so, the
motor may indicate that it is operating in power
limit under certain conditions by displaying code
“66”. Remove the restrictions or reconfigure the
duct work to avoid this code.
B. Is the motor set-screw not tightened to the motor
shaft? This may cause erratic motor operation
and cause the furnace to display a “66” fault code.
Further, airflow will be low or air may not be mov-
ing at all.
3. INTERNAL ERROR – MOTOR UNABLE TO OPER-
ATE (FAULT CODE “61”)
If the blower motor is able to communicate with the
furnace control but is experiencing an internal issue
– such as overheating, the fault code “61” will be dis-
played. Internal overloading may reset once the
condition causing the problem has been removed.
However, it is likely that the motor will need to be re-
placed.
A. Is the motor wheel blocked by an obstruction? If
so, the motor may be in locked-rotor state and the
furnace control will report fault code “61”. Re-
move the obstruction and try to operate the motor
again. If the motor continues to fail, it may be
permanently damaged and may need to be re-
placed.
B. Is the motor overheating? If so, it may report an
overheat condition to the furnace control and the
control will report fault code “61”. Determine the
cause of overheating and repair. Try to operate
the motor again. If the motor continues to fail, it
may be permanently damaged and may need to
be replaced.
4. INTERNAL ERROR – MOTOR ABLE TO
OPERATE (FAULT CODE “60”)
This is a low-level fault that is not likely to be dis-
played often. Operation will continue as normal but
fault code will be displayed. Long-term permanent
damage to the motor is not expected.
DIAGNOSTICS
DIAGNOSING BLOWER MOTOR ISSUES
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