X-13 Motor Troubleshooting

In a previous post , I explained what an X-13 (constant torque) motor is and how they operate.  Now that you understand what it is, now we can discuss how to properly troubleshoot the X-13 motor.


Before troubleshooting any HVAC system, it’s a good practice to become familiar with the components and wiring diagram, check for and follow any on board diagnostics (fault codes in the manufacturer’s control board). On X13 motor systems (as with any blower) it’s also a good practice to check the tap (speed) selections and delay (both on delay, if available, and off delay) settings on the control board. The unit’s manuals will typically be required for these settings and can also provide valuable sequence of operation and troubleshooting help. (When all else fails, read the instructions).

If the motor is running but the system is noisy, shutting down on its limits or safeties or the evaporator coil is freezing, there is a good chance the motor is good. The problem is most likely external to the motor.

-Check the tap selections using the manufacturer’s guide for cfm vs. static pressure (proper air flow).

-Check the air distribution system components for dirty components and closed dampers, registers and grilles.

-Check the system static pressure and make repair(s) if it is above the manufacturer’s recommended maximum level.

If the motor is not running, the following checks will diagnose whether it is a good or bad motor. Always disconnect the power to the HVAC system before disconnecting or reconnecting any connectors to these motors.

There are two inputs needed to operate this motor, (1) a high voltage constant power source, and (2) the communication that selects the torque value (cfm) in each tap per demand.

Checking the High voltage input : First check the high voltage to terminals (L) and (N). There should be 115vac or 230vac, depending on the model, between these two terminals whenever there is power to the system, regardless of a demand call.  Applying incorrect high voltage to the X13 motor may cause the motor to not operate, or even damage the motor. On 115vac systems, make sure the polarity or the power connected to the motor is correct. If this voltage is missing, fix the problem in the system and try to run the motor. If the voltage is within ± 10% of these ratings then move on to the next step. If the voltage is above or below the ± 10% of these ratings, fix the voltage problem first, and try to run the motor. Proper grounding should always be checked and repaired if needed.

Also, if you read my post on X-13 motors in 3-phase systems, both power legs to the X-13 motor must be the same.  You cannot use the “wild or stinger” leg on a 3 phase system.

Checking the communication input

The following information must be known before troubleshooting the low voltage communication to this motor.

  1. Which tap(s) have been programmed and what are their purposes (heating airflow, cooling airflow, continuous fan airflow).  In other word, which is High, med high, med low, low-speed in relation to the positions on the motor. Keep in mind, even though the motor has 5 possible inputs, with some applications, all of the taps may not be programmed. Use the manufacturer’s wiring diagram or sequence of operation to see what taps are used and programmed.
  2. Where on the manufacturer’s controls or circuit board does the low voltage communication come from by demand or mode?
  3. The sequence of operation of the manufacturer’s controls or circuit board (where the low voltage communication is sent from the unit control to the motor from each thermostat demand and if there are any delays).

If no low voltage communication (typically 24vac) is measured at the motor on taps 1-5, check the HVAC system wiring, controls and demand call.  Always check low voltage between terminals 1-5 and (C) at the motor, never ground. Once the problem is corrected, confirm that the low voltage communication is applied to a programmed tap.  If proper low voltage communication is present at a programmed tap, with proper high voltage to the motor and it still does not operate, the motor is failed. A direct replacement motor from the manufacturer for the same model and size unit is required.  X-13 motors, like full ECM motors have a factory program in them for the specific model.  You need to make sure you replace an X-13 motor with the correctly programmed motor.

If all the taps are programmed, you can try moving the 24 volt  input from one tap to another to see if the motor will operate.

As mentioned above, if you do find a failed motor, you need to replace it with a correctly programmed one.

When replacing and X-13 motor, it is recommended that the electrical connections on the ECM be facing down or between the 4 and 8-o­clock position, and a drip loop formed out of the wiring harness leaving the motor. This is to prevent any moisture or water that may get into the motor area from running into the connectors where it could cause damage to the control. Also, the X13 motor should be mounted so that the belly band does not cover any of the motor vents, and is not located in the “Keep Out Area” approximately 2.75” from the control end of the motor.

In most systems, the manufacturer will install the motor in the correct position and provide the drip loop. However, keep in mind when multi-position systems are installed in a position other than the way the manufacturer constructed it, the motor may need to be turned and the drip loop re-arranged.

One last thing to remember, with all ECM and X-13 motors,  the variable speed ECM may rock back and forth when it first turns on. This is normal operation for the control to figure out the proper direction to operate the motor.

Hopefully, this post will help you diagnose the standard ECM X-13 motor.


About yorkcentraltechtalk

I have been in the HVAC industry most of my life. I worked 25 years for contractors on anything from residential to large commercial boilers and power burners. For the past 23+ years I had been employed by York International UPG Division ( a division of Johnson Controls) as a Technical support/Service Manager but I am now retired. One of my goals has always been to "educate" dealers and contractors. The reason for starting this blog was to share some knowledge, thoughts, ideas, etc with anyone who takes the time to read it. The contents of this blog are my own opinions, thoughts, experiences and should not be construed as those of Johnson Controls York UPG in any way. I hope you find this a help. I always welcome comments and suggestions for postings and will do my best to address any thoughts, questions, or topics you may want to hear about. Thanks for taking the time to read my postings! Mike Bishop
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58 Responses to X-13 Motor Troubleshooting

  1. Whit Perry says:

    I had a few students sign up. We are learning each week from your posts. I also put this in my newsletter. Hopefully you will get more readers. This is fantastic learning material…. I will probably add it to my December newsletter for those who didn’t see it.

  2. bill says:

    Indeed this is great learning material.

  3. Phil says:

    thanks for the clear instructions. Using these instructions helped me determine my x13 blower motor has died. The unit is 3 years old (Carrier). In my other Carrier unit, the x13 motor died in in 18 months. Are these thing unreliable? Fortunately both are still in warranty, though I have to pay labor costs.

    • The whole purpose of my posts is to make things as simple as possible. X-13 motors are very reliable. If you are having problems, it could be irregular power to the motor or problems with the “control (24 VAC) side of the motor.

      • Jack Sieh says:

        Hi mike
        thank you for the x13 posting. i have a question is that i was read the other posting the tech say checking Hi volt between N-L1=230v but my is 250v i think that is OK. but he say on the low volt side checking between N-2=24v but it show 125v ?????. and you post say checking between C-2=24v which is correct ? Thanks.


  4. Cynthia Karabinos says:

    I am not a tech, but a lay woman. Yesterday my so called A/C company came out and found 2 leaks to the tune of $360. Tried turning on the A/C and the X-13 evaporator motor was bad, of course, the component is under warranty, they want $500 to order, ship, install and program. What does “program” mean? It wasn’t 6 months ago that they nailed me for another $300 for 2 leaks found. This unit is under 5 years old, and already I am having to invest $1,160 to keep my A/C running.

    My question, how hard is it to install a evaporator unit? I purchased a 3 ton Rheem and all of a sudden all of these problems are occurring. Any help/feedback would be greatly appreciated. I just don’t want to feel like an idiot not knowing what they are doing, and right now, I feel like this company is really ripping me off. Thank you in advance for your help.

    • program means they would need tohave a “computerized program” put into the motor to match the model number of the furnace. Each ECM or X-13 motor can come from the manufacturer programmed which they shouldbeable to order direct from the manufacturer, or it can come out with no program in it and would need to be programmed locally either by them of by their disrtributor.
      My suggestion would be to contact the lcoal Rheem distributor, or contact Rheem customer relations on the internet and see how they handle these.

  5. Mike says:

    Thanks for the info

  6. George says:

    Could comm and spt cool be wired to a 24vac relay coil to operate a psc for an emergency repair? Or would the low amp draw from energizing the relay coil be to much for the oem circuit board to handle? Thank you

  7. glen says:

    ecm motor rocks back and forth all the time and will not turn in one direction is it the moduel or could it be the contol board. model rhllhm4824ja

  8. Ryan says:

    This was a great read!! All I can say is absolutely perfect. How do I get more of your articles? I found this through a google search on the x13

  9. Chris Constant says:

    Would using a surge protector on the furnace circuit help with the ECM motor module failures ? Seems every one I have found burns at the diode in the module . Or is this a poss prob with low voltage ?

    • see my post titled ” PF Choke for ECM Motors” Hopefully this will help solve your problem. Also — see my posts on ECM motors. T^o find any of these posts, just type a key word in the search box.

  10. Joe M. says:

    I have a Carrier Infinity 96 (58uvb080-20). I intermittently receive a code 41 on my thermostat and the ac will not come on. Then several minutes latter the ac will operate like normal and cool the house. Sometimes the code 41 is followed by a “change air filter” notification. I installed a brand new merv 8 filter and still have the same problem.

    On some days I could get the code 41 two or three times, some days not at all.

    Could this be an ECM/motor problem?

    • as much as I would like to help you, I am not familiar with the Carrier Infinity furnace and it’s related flash codes. I would suggest contacting your dealer or distributor for assistance with this.

      • Joe M. says:

        Thank you for your quick reply. The code 41 is for “Blower Motor Fault”.

        I guess I was wondering with ECM’s in general, does it sound right for them to work intermittently or completely fail altogether?

        Most of what I’ve be reading has been about ECM motor complete failures and determining whether it’s the motor or module.

        I will have someone take a look at it. I was just trying to get an idea of what the problem could be.

      • in my experience, the ECM is either good or bad. Usually not intermittent. It could be something as simple as a loose connection at the motor. I could be the control board is seeing something and giving the flash code 41. Again, I am not familiar with Carrier but ecm motors/modules prettty much all work the same. The only difference is how they are programmed and how they run, either off 24 volt signals from the thermostat of via PWM signals from a control board.

  11. Joe M. says:

    Thank you.

  12. Luis R. says:

    I’m getting 28V at the tap. Is this ok?

    Symptom: the blower will spin VERY VERY slowly. So slow I can see the individual blades as it spins. I get 240V on the voltage plug. It’s on a Carrier FB4C. Thanks

    • do you have 240 volts between L and N? Do you have 110 (120) to ground at each power lead? Both line voltage leads MUST be the same.
      Do you have 28 volts between speed tap and C? between speed tap and Ground? Have you tried moving the speed tap lead to one of the other speed taps? If all of this is correct, then you probably have a bad X-13 motor

      • Luis R. says:

        Yes to all the above except I have not tried a different tap yet. The motor is intermittent. It started to run for now. Being it’s late, I will let it be for now till morning. Thanks for the quick response!

  13. Bill. L says:

    luis r. I am having the same issue. Did you get your motor working?

  14. Joe M. says:

    I just wanted to update my situation. It turns out that the ecm motor module was to blame. I have since replaced it and the furnace is working just fine. The thermister looked new. So, I’m guessing that it could be a capacitor, resister, mosfet, etc. on the module that’s on it’s way out and that’s why it was intermittent.

    • Glad you solved it — see my post titled– “PF Choke for ECM Motors”. That may help you prevent future failures.also, since your motor appears to NOT be an X-13 motor — see my posts on ECM motors

      • Joe M. says:

        Thank you for the reference to the article. I did read it. In fact, I read many articles in this blog because I find it very interesting. Great work!

        This particular ecm motor did have a pf choke. From what I understand, any Carrier ecm motor that is 3/4 hp or 1 hp has a choke.

        Thank you again for your assistance.

  15. Airton says:

    First, thanks for writing these blog posts. Learned a lot!

    I have a Comfortaire installed in 2010. Recently (past week) the blower GE x13 motor has been fickle as to when it needs to operate. If I let the system it for long hours, I can fire it up without a errors. Once the desired temp is reached. When the thermostat kicks the system back on again the blower motor acts up. Everything else in the a/c system run fine. The blower motor will spin backward and forward for as along as I leave it on. I make sure to shut of the a/c so the inside doesn’t freeze. I’ve cleaned everything I can to try and remove anything that maybe be triggering the errors. Not sure if it’s the module or what….

    Sweating in Orlando,FL

  16. jorge says:

    For humidity control I want to Know if it possible change the 24V communication tap position to a lower speed while the x13 is running (high voltage is connected). I think that using a single pole double throw relay and a thermostat with humidity control I can do that.
    What is your opinion about?
    Thanks a lot in advance.

    • the x-13 motor has 5 speed taps positions but, depending on the manufacturer, they may all or just some be programmed. Mosst are set up to operate at least 2 speed, single stage heat and single stage cool but that is from the unit’s control board.
      You will need to verify that the speed tap you want to use is programmed. Then you need to make sure that you do not have ANY POSSIBILITY of 2 speeds operating at the same time. If you can do that, then you should be able to accomplish what you want.
      STANDARD ECM MOTORS already have that capability.

      • jorge says:

        Thanks a lot for your prompt response.
        Important observation from you.
        Never apply two speed simultaneously!!
        Kind regard.

  17. Pete Singh says:

    If the customer can’t afford $1500.00 for the replacement of E C M motor, (warranty expired) can it be replaced with regular PSC motor?

    • There is a difference between ECM and X-13 motors. If you have a true ECM motor, see my post titled — ECM “Emergency” Motor Replacement. Keep in mind that you will only have a single speed operation to cover both heating and cooling or will have to make the change every spring and fall. Also, you need to verify with the manufacturer if their control board will function as described in the post. If it does, then you can put in a psc motor to replace an ECM

  18. Jacob Hollub says:


  19. Gunter says:

    Very informative pages. Mr Singh’s question was, I believe, if he can convert to an (old fashioned) multi speed ac blower motor. I think that should be possible by tapping the output of the heat and cool relays on the control board, using another extra set of relays to control the power to taps of the multi speed motor. Please correct me if my thinking is faulty.

    I also have a problem with my blower motor on cooling. It runs on the high speed only intermittently. When off the high speed it reverts to the low heat speed. If I pull the wire going to the motor from the low heat relay the motor stops. I have not yet taken out the motor of my Goodman GME8 1155 CXA furnace (its 100 deg F up in the attic) so I don’t know the exact model number, but when I asked for a replacement motor and they sent me an x13. I presume I have motor controller problem as the voltage output from the furnace board seems ok. Your comments would be highly appreciated.


    • First, see my post from January 1,2013 titled ECM “Emergency” motor replacement. This is for true ECM motors.
      If you have an X-13 motor, and the board is sending the correct control voltage, yes, you can add relays to switch the line voltage to a PSC motor. You need to be sure that you only have 1 motor speed tap energized at a time or you wthe motor will burn up.

  20. tt120str says:

    I bought a 3 tons Rheem with an x-13 motor almost three years ago. Last week, the x-13 motor started acting up; I am getting some kind of noise as if there is not enough juice to power the motor. How do I know if it is controller or motor issue?

    • First of all, if the unit is only 3 years old, the motor is probably still under warranty. You should call your installer who can properly diagnose the problem.
      With that being said, if the motor runs but is noisy, you could have air flow restriction like dirty filters or a damper that somehow got shut. Otherwise, if you follow the steps for troubleshooting in the post, you should be able to determine if it is the motor or control.

  21. Raj says:

    I have two accounts units which have X13 motors. Both are moving back and forth but do not run. Mechanic said modules are bad and need to be replaced. Is the r email any way to fix the module?

  22. I have a question. I recently replaced my ecm module with a new one. Two days later it failed. it started doing what the first one did. The motor runs at a very slow speed but pulses like it is trying to kick into a faster speed. Is something else the root of my problem? Any help would be most appreciated. It is a York B3hp030a06a.

    • This is not a lot of information to make a proper diagnosis. When an ECM motor pulses, it is usually a sign of high static pressure. Your tech should check for any possibility of duct/air flow restriction.

      • Please indicate any info you may need, I will try to supply it. My unit is about 8 years old and has been cleaned and maintained. All of the coils are clean. No parts of the unit have been replaced except the ecm module. My question today is….If the air filter is clogged, with dog hair, really bad, would it cause the ecm to fail. I forgot I put an all natural filter in and have not cleaned it in a month or two. I looked at it this morning and it was clogged up. I am wondering if I killed another ecm by not cleaning the filter. High Static?

      • High static could have been the cause of the ramping up and down searching for where it could operate. When static pressure excess 0.8 to 1.0 IWC the ecm will do that. Whether the motor was dead, the TechMate tool would have diagnosed the motor to see if it was still working.

  23. No Techmate tool. If the motor still operates at low speed, is there any chance it will still work if I clear the blockage (put a new filter in). I just don’t know much about the ecm motors.

  24. Emmitt barnes says:

    My x13 runs intermitantly on its own . I replaced the board , the main board and it still will start up and run ever so often

    • An X-13 motor is controlled by low voltage ” commands”. Your thermostat could be the problem, the wire, and you should check your safeties since they can also turn on the motor (like a tripped limit?).

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