Posted on 2 Comments

Problem: The fan on the unit recently started running continuously at low speed. The only way I can stop it is to cut the power at the disconnect.

happy AC small

Problem: I have a Carrier A/C condenser unit model 38CKB036. The fan on the unit recently started running continuously, and runs at about 400-500 RPM vs. the rated 1500 RPM. The only way I can stop it is to cut the power at the disconnect. I have replaced the dual run capacitor with no effect and have removed and cleaned / check the contactor. Any idea what can cause this?

Answer: This problem can be caused by a short to ground in the motor or a short to ground in the motor wires that lead to the motor. With a single pole contactor there is 110 volts always applied to one lead on the motor at all times, and even if the contactor is not energized it can supply 110 to the motor. If the motor or wires are grounded out then it will run half speed. I would suggest turning off the power (of course), take the black and yellow wires loose from there connections. Use an ohm meter and check from the black to ground and yellow to ground. If you get any resistance then the motor is grounded out and you will need a new motor or repair the wires on the motor. Please send us your air conditioner or heat pump unit’s model number if you would like for us to use our online program to look up and find out which OEM fan motor part number you unit uses. Our email address is: arnoldservice@gmail.com It is always easier to replace the motor with an OEM part rather than use a universal motor which requires several wiring changes. Please click here if you would like to see the condenser fan motors that we sellBelow we have a YouTube video which shows how to change out a condenser fan motor. This YouTube video was made by djjunb. Thanks so much djjunb for making this informative video. I hope you can easily find the problem and repair your air conditioner or heat pump. If you have any questions please email us or comment near the bottom of this page. Thank you so very much for your interest and support! We would love to help you out and have your business!

2 thoughts on “Problem: The fan on the unit recently started running continuously at low speed. The only way I can stop it is to cut the power at the disconnect.

  1. Turning ac on the fan runs 5 min. Then stops out side unit.

    1. Hi Richard! This might be s fan motor that is going bad, a weak run capacitor or you might have a stoppage in the refrigeration cycle that is causing one of the high or low-pressure safety controls to turn off your AC unit. We have a post with two YouTube videos about the problem that you are having on the following page: https://arnoldservice.com/problemoutdoor-condensing-fan-motor-has-stopped-running/ If you have any questions please let me know by emailing me at arnoldservice@gmail.com. I hope you can easily find and fix the problem.

Leave a Reply

Your email address will not be published. Required fields are marked *