Table of Contents
Variable Speed GE ECM Motors - When you look at buying a new HVAC system it will surely arise when the HVAC salesman or HVAC contractor who comes to give you an estimate will show an HVAC system that has a variable speed motor or the GE ECM (Electronically Commutated Motor) installed in it. These are systems that have a higher efficiency rating than the HVAC equipment that has the typical electric blower or condenser fan motor.
The ECM (Electronically Commutated Motor) uses less energy than the standard PSC motor that is commonly used in air handlers and condensers to move air. The ECM motor also offers more control which has good benefits in HVAC applications.
Variable Speed GE ECM Motors
We have many other related articles. Please use the search feature to the right to help you find other related articles.
HVAC Motors That Save Energy - Variable Speed GE ECM Motors
GE or General Electric and Emerson (to name a few) produce variable-speed ECM motors for the HVAC industry. The HVAC manufacturer then takes these ECM motors and installs them inside their air handlers and condensing units. Not all ECM motors are variable speed. For example, in condensers, the motor has a fixed speed the same as many standard PSC motors.
The reason manufacturers use the more expensive ECM motor and run them at fixed speeds is because they use less energy than the standard PSC motors commonly used in condensing units. This allows the condensing unit to use less energy and gives the HVAC equipment a higher SEER rating.
Typically the ECM motors in the air handlers are variable speed but require a control board to control the speed to ramp up and down according to what the controller is calling for. The control boards can also be set to change the amount of air the ECM blower moves through the air handler.
This is commonly done with dip switches and gives the manufacturer a lot of flexibility for offering a single air handler that can accommodate different airflow capacities.
How the ECM Motor Works as a Blower – Variable Speed GE ECM Motors
Trane, Carrier, Rheem, York, and all the big HVAC manufacturers (and a few small ones also) have their own tagline for describing the ramp up and ramp down for the ECM blower motor.
The air handler will turn on and ramp to 50% (or whatever percentage the manufacturer deems appropriate) and then after so many minutes as determined by the program the ECM blower will ramp to 100%. When the thermostat satisfies the motor will slowly ramp down and then stop after so many minutes. This is often referred to as soft start and soft stop.
We have many other related articles. Please use the search feature to the right to help you find other related articles.
The typical PSC motor starts and immediately goes to 100% and then stops almost immediately (aside from inertia) when the thermostat satisfies. The benefit of this is it can reduce humidity in the air when the unit first starts. This is important in the summertime when humidity levels are typically high in many geographical areas.
The less the humidity in the air the cooler you will feel. A big part of air conditioning is humidity removal and the variable ECM blower motor helps humidity removal when the motor is stepped up as described.
Efficiency Ranges and Other Factors for Variable Speed GE ECM Motors
The ECM motor (Electronically Commutated Motor) is preprogrammed to run at certain speeds as determined by the HVAC manufacturer such as Trane, York, Lennox, or Carrier. The first stage in the program is usually a lower speed in the cooling cycle to remove humidity.
A slower rate of an airflow across the evaporator coil allows the cold evaporator coil to remove the humidity in the air. The second stage of the ECM motor is usually 100% peak speed as designed for CFM’s and tonnage of the system.
From low to high speed the ECM (Electronically Commutated Motor) maintains a good efficiency range between 60% and 80% between all speeds versus the PSC motor with multiple windings getting between 10% efficiency at lower speeds to nearly 50% efficiency at higher speeds. As you can see that no matter the speed of the ECM it maintains efficiency and reduces the amount of electricity consumed to do the same thing the PSC motor does to move air.
Another bonus for the ECM motor especially in cooling mode is the fact that the temperature of the motor is constant and typically at or near ambient temperature whereas the operating temperatures of the PSC motor are 90 degrees F. to 170 degrees F. This means the air conditioner that uses the PSC motor must also overcome the heat generated and added to the system by the PSC motor while the heat added to the system with the ECM motor is nil to none.
Common Sense Protection for the Variable Speed GE ECM Motors
ECM motors are here and they offer a higher efficiency because they use less energy and provide benefits that the typical PSC motor cannot offer. ECM blower motors have been around for a while and have proven their reliability in HVAC applications. They are not trouble-free though as with any mechanical or electrical device problems can occur. To prevent some of the problems that occur it is recommended that surge protectors be used because of the solid-state controls that control the ECM motor.
Surge protectors can be purchased at most electronic stores and even some HVAC wholesalers offer surge protectors. By purchasing the air handler or gas furnace and condenser with an ECM motor you will consume less energy when your air conditioner or heating system is running. This means lower utility bills and more money in your pocket in the long run.
Variable Speed GE ECM Motors Additional Information:
- Variable-speed ECM motors offer higher efficiency than other motors.
- Variable-speed ECM motors if programmed and set properly improve system temperature, humidity, and capacity.
- Variable-speed ECM motors can vary the speed based on input from a control board.
- Variable-speed ECM motors enhance the efficiency of an HVAC system.
- Variable-speed ECM motors offer slow start or soft start capabilities.
- Surge protectors should be used on the circuit with Variable speed ECM motors.
- Variable-speed ECM motors can be used in both the condenser and the air handler.
It is essential to gain all the benefits one can gain from these motors that they are programmed and set up properly. The programming part is up to the manufacturer while the setup part is up to the installer. This is why it is crucial to select a qualified and properly trained contractor to install your new system.
Other resources for Variable Speed GE ECM Condenser & Blower Motors can be found in our resources section below. High Performance HVAC also has additional HVAC Motor articles:
- Electric Motor Basics
- Condenser Fan Motors
- Air Handler Blower Motors
- Air Conditioning Maintenance & Repair HVAC Motors
- Motor Controls for HVAC
- Control Circuits for Air Conditioning and Heating Systems
- Disconnect and Electric Motor Starter with Overloads
Variable Speed GE ECM Motors
I just replaced the module in a 3 ton York Heat Pump (the old one had a burnt broke part). The blower worked and ramped up but now the blower motor will not ramp up. What would be the cause or parts to replace.
Not enough information for this technical subject. You would likely be better off calling a pro as they have the correct tools to properly troubleshoot the problem. Some of these ECM’s require a special tool to read out what the problem is. Each one is different in some cases such as Trane has their own diagnostic tool that will give you codes for problems. I am not 100% certain about York but I’m sure they also have proprietary parts that will only work with their own tools (which they sell).
Can I use an ECM motor if I have a EWC zoning system? I’m getting conflicting information on replacing an hvac system. One guy said it’s ok. One guy said it would cause trouble with I think he said back pressure when one damper was closed. I’m looking at getting the Trane XR14.
The problem is control. You can do it but when you close a damper you need to reduce the airflow to avoid the back pressure. It can be controlled with either a pressure sensor and controller or by damper position, however this would likely be extremely expensive.
Thank you so much!
I have a carrier unit I have replaced the existing ECM motor was a GE 3.0 ECM I put in a new ECM motor however the furnace is looking for a signal that the motor is running at 250 rpm’s my furnace is locked out because it does not receive signal from new motor I have is a Genetech replacement for the Ge
The old motor had a common 2 speed Rx TX. And a v+. The new motor has a common and 4 speed wires. No V+ . I believe the v+ is a 24 V output from the motor. Any ideas
Rule of thumb especially with electronics and especially with certain manufacturers like Carrier and Trane is to use an exact replacement. Carrier parts are typically proprietary (which makes them expensive) so you may have to either re-engineer (not recommended) or go to Carrier or a Carrier dealer for the right part.
I have an Armstrong Air handling unit with an ECM motor, I do not believe it is variable speed, The ECM module is dead on my motor, the motor is only sold as one piece and its 1,100 dollars to replace, Can I replace my ECM motor with a different motor that has the same ratings as the original…
Yes you can but you will lose efficiency, mess up any warranty, and potentially cause lots of other problems. You also have to make sure you get RPM’s correct otherwise you will have problems with the evaporator coil freezing or other issues with the refrigeration system. Not sure what the RPM’s of the new motor should be as the are different motors for different air handlers for blower speed and it depends on the blower wheel and some other factors. The most important part is get the proper amount of CFM’s across the evaporator coil otherwise you will cause more problems than not. The wiring for a technician should be pretty cut and dry. You will likely have to add a relay to control the blower if you convert it. Honestly, I do not recommend it unless you really know what you are doing. I know it can work and save you money but I would not do it myself unless I had specific written instructions from the manufacturer.
I have a Trane air handler model TWE031E13FBO. The ICM motor starts up and as it ramps up in speed I get a sudden buzzing sound and the motor turns off and then repeats this cycle . I was hoping to get advice on what part would be the culprit ?
ICM Fan control board?
Motor Module?
Motor?
Is there any particular surge protector rating that you would recommend? Any particular surge protector brands?
My ECM failed due to a surge at least that is what I am being told. We definitely smelled a plastic/rubber smell the night before.
Really good information on your site.
It really depends on the type of system you have but you can purchase the surge protectors that go in the main electrical panel and will protect whatever circuit or range of circuits you have installed in the panel. If you have a heat pump then you have a larger circuit than you would for an air conditioner as most heat pumps have electric heat strips. The best thing to do to properly protect the system is to take a load calculation of the system and protect everything from the main panel.
Can an older furnance (Heil) have a blower motor replaced with a ECM motor? Thanks
Yes as long as you maintain the proper RPMs of the old motor and do not exceed the temperature limitations of the safety limits. For a novice I do not recommend it.
I just had a Rheem furnace with ECM installed. Connected to an ecobee thermostat. The fan does not ramp up or down, it come on blowing pretty hard and shuts off without slowing. Not sure what could cause this. I removed the g wire from the tstat and same thing.many suggestions?
A) It is not an ECM blower or B) it has not been set up properly. The settings for this are in the air handler and on a board with several options for fan set up and control. You’ll need an installers guide to see the settings. The settings can range from the amount of CFM’s the fan outputs (which is very important for the correct airflow and the size of the furnace) and soft-start or slow ramping.
The settings are also different from heating to cooling if the furnace is matched with an air conditioner. Slower speed for heating and a faster speed for air conditioning with the ramping options for air conditioning which helps dehumidification in the summer. Additional program options include a delay after the thermostat is satisfied to keep the blower working to expend the energy in the system before shutting down. For a furnace that is a cool-down function to cool off the heat exchanger.
Not sure about the current Rheem models but on other manufacturer’s these settings are done by an array of dip switch settings and it is very important to get them right especially for CFM’s.