Fixing and repairing ECM motors

Discussion in 'Maintenance and Troubleshooting' started by HVAC Technician, Apr 24, 2013.

  1. I almost posted this on a different website, but decided to post this here because Electronically Commutated Motors ECM are being accepted quickly in our market and most of us are now using them. I know a few facts but not too much about these motors. I don't feel an immediate need to say more than that they are DC brushless motors which typically can save from $100.00 - $300.00 per year in energy costs. I believe they originated in Europe and then caught on here. Twenty years ago they were new and very expensive to replace. Reliability was then unknown. Today they are considered fairly reliable and nearly as expensive, if a few dollars cheaper to replace. If you have a newer unit with extended parts warranty, and one fails, stay with the original factory motor and parts, right ? However once the unit is out of warranty you or I might want to consider cheaper options. Consider that one of the failures in one out of three failures on earlier ECM motors has been burn-out of a 20 or 30 amp thermistor in the electronics section which is usually replaceable. (See my link to another site at bottom) I just got back from a Johnstone Supply jobber display and I know that "Evergreen" www.the and Rescue select motors have both retrofit motors for older permanent split capacitor motors and supposed new ones ? equivalent ? to original equipment. So what is my point ? We all want cheaper repairs. It is not always possible to "get" the electronic board section alone. For those techs who cannot get the separate board, the whole motor must then be replaced even if the motor is still is good mechanical condition. Bill ? Typically $1,100.00 + Some people have been replacing a simple burned out thermistor and restoring their unit to service for less than $60.00 ! The other site mentioned that GE is totally silent on the fact that some of the older GE ECM motors are repairable. What we are looking for is really drop in, exact replacement because of specific connectors. Many of these units have complicated control and function. And there is one other thing to point out. There are now generic, (more or less) ECM replacement motors than can be retrofitted to older furnaces, AC evaporators, etc. that were originally equipped with permanent split capacitor motors. They work. But those are NOT designed for 96% of the units discussed on this blog. So at this point I invite those with more experience to share what they are learning. My own unit is a Carrier GTPX Model 50YDH026PCK301
  2. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    My limited understanding of ECMs is that each OEM programs, perhaps via firmware or similar download to the motor control board, a map of how they want the motor to respond to various inputs.

    I've browsed but never found a "secret decoder", something along the lines of "apply 0-10 Volts DC to terminal 13 to ramp the fan from 0-100% output"

    I like the idea of trying to hack these things as well as finding a way around replacing a perfectly good and pricey motor when the only failure is some 17 cent control board component that died during a power spike.

    Keep us informed!
  3. If I remember right one of the venders indicated that the "Rescue" brand ECM motors could be configured for specific brands and models at the counter. I will share what I learn in the future as I learn it. I know that our local Carrier and Trane parts places sell troubleshooting "kits" for ECM motors.

Share This Page