Carrier 40MPHA Service Manual page 31

E3/F5 (Fan speed is operating outside of the Normal Range)
Description: When the indoor fan speed maintains a low speed (ex. 300RPM) or a speed that's too high (ex.1500RPM) for a certain time, the
unit stops and the LED displays the failure (E3). When the outdoor fan speed registers below 200RPM or over 1500RPM for an extended
period of time, the unit stops and the LED displays the failure (F5).
Recommended parts to prepare:
• Wiring
• Faulty fan assembly
• Faulty fan motor
• Faulty PCB
Troubleshooting and Repair:
Power off. Wait 2 minutes then restart.
Does the problem exist?
Shut off the power supply.
Rotate the fan by hand.
Does it turn easily?
Check the fan motor wiring.
Is it improperly wired ?
Measure the voltage for
the fan motor from the PCB.
Is it within normal parameters?
Replace the fan motor.
40MPHA-03SM
YES
NO
YES
YES
YES
Specifications subject to change without notice.
NO The unit is operating normally.
Find the cause of the problem and resolve.
Ensure proper connections.
NO
Replace the indoor /outdoor PCB.
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