Electric Motor Testing and Troubleshooting: ECM Motors and Control Modules

Follow these steps and guidance for models 2.0 / 2.3 / 2.5 / Eon^® / 3.0

1. The most efficient way to install the motor is to have the control already attached.
2. Make sure the belly band mount is on the motor module only and is not covering any of the motor shell holes. Typically, the belly band is located between the two sets of motor shell holes.
3. Before tightening down the belly band, rotate the motor until the connectors in the control are facing down or at least between the 4 and 8 o’clock position in the blower housing, as it will mount into the HVAC system.
4. Center the blower wheel in the blower housing and tighten the blower wheel hub bolt on the flat portion of the motor shaft.
5. Reinstall the blower/motor assembly into the HVAC system by following the manufacturer’s guidelines.
6. Plug the 16-pin or 4-pin communication connector and the 5-pin connector back into the motor. The connectors are keyed. Observe proper orientation
7. Be certain to form a drip loop so that water cannot enter the motor by draining down the cables.
8. Go to the Final Installation Checks section

Endura^® Pro Standard ECM Motor Diagnostics

IF THE MOTOR IS RUNNING:

1. It is normal for the motor to rock back and forth on start up. Do not replace the motor if this is the only problem identified.
2. If the system is excessively noisy, does not appear to change speeds in response to a demand (Heat or Cool), or is having symptoms during the cycle such as a tripping limit or freezing coil, check the following:
1. Wait for programmed delays to time out. If delays are too long, reset them using the manufacturer’s charts.
2. Ensure the airflow settings are correct for the installed system using the manufacturer’s charts. If the system is operating normally in each mode, there is no problem.
3. Remove the filter and check that all of the dampers, registers, and grills are open and free flowing. If removing the filter corrects the problem, clean or replace with a less restrictive filter. Also check and clean as needed the blower wheel, secondary heat exchanger (if applicable) and evaporator coil (if applicable).
4. If this does not correct the problem, check the external static pressure. If it is higher than the manufacturer’s recommendations, correct the airflow restriction.
3. If the motor does not shut off at the end of the cycle, check the delay times and wait for the delays to time out. Also make sure that there is no call for “Continuous fan” on the “G” terminal. This motor may take a while to come to a complete stop with selected delays.
4. If the above diagnostics do not solve the problem, confirm the voltage checks in the next section below, then continue diagnostics in the section, Endura^® Pro Standard ECM Motor Communication Diagnostics. The TECINspect^® Service Tool is not designed for use on this motor.

IF THE MOTOR IS NOT RUNNING:

1. Check for proper high voltage and ground at the (L)(G)(N) connections at the motor (see Figure 8). Correct any voltage issues before proceeding to the next step. Endura Pro motors are voltage specific. Only the correct voltage should be applied to the proper motor. Input voltage within plus or minus 10% of the nominal 115VAC, 230VAC, 277VAC or 460VAC 1. 3. 4.
2. The TECINspect service tool is not needed for use on this motor. If the motor has proper high voltage and ground at the (L)(G)(N) connections, continue diagnostics in the next section, Endura Pro Standard ECM Motor Communication Diagnostics.

Endura^® Pro Standard ECM Motor Communication Diagnostics

Endura Pro motors can be communicated through AC or DC low voltage. AC voltage is typically 24VAC and DC voltage can be between 9-23VDC (see Figures 9 and 10).

1. Start with the manufacturer’s literature to confirm proper set-up, connections and voltage. It is not required that all terminals on the motor have a program. If the low-voltage communication is applied to an unprogrammed terminal, the motor will not operate, which is normal.
2. Initiate a demand from the thermostat and check the voltage between the common and the appropriate motor terminal 1- 5. Confirm the meter is set to the voltage identified from the manufacturer’s literature (see Figures 9 and 10).
1. If low voltage communication is not present, check the demand from the thermostat. Also check the output terminal and wire(s) from the manufacturer’s control board or relays to the motor.
2. If the motor has proper high voltage as identified in the previous section, and proper low voltage to a programmed terminal, and is not operating, follow the next section on Replacing the ECM Control Module.

Replacing the ECM Control Module

For Endura^® Pro

Before replacing the electronic-control module, you must test the motor module to ensure it is not also damaged. Installing a new control on a failed motor will result in no operation, improper operation and/or potential failure of the new control. Procedures for testing the motor module are included below:

1. Disconnect AC power from the HVAC system. Unplug all wires and/or connectors. Note tap position of all individual wires from the motor control.
2. Remove the blower assembly from the HVAC system if needed.
3. ONLY after the system AC power has been off for 5 minutes, remove the two (2) hex-head screws from back of the control.
4. Unplug the 3-pin connector from the inside of the control by squeezing the latch and gently pulling on the connector (see Figure 11). Now you’re ready to test the motor.

Motor Module Tests

The Winding Test

Set ohm meter to the highest possible setting and measure resistance between each of the three motor leads to the unpainted part of the x-brace. The motor passes the test if the meter indicates greater than 100k ohms.

The Phase-to-Phase Test

Set ohm meter to lowest possible setting and measure the motor phase to phase resistance by checking these combinations of the 3-pin motor connector with an ohm meter:

Lead 1 to lead 2

Lead 1 to lead 3

Lead 2 to lead 3

For the purpose of this test, either end of the 3-pin plug is lead 1. Resistance values should be less than 20 ohms and each of the three values should be the same (plus or minus 10%). If the measured resistance is outside of these parameters, the motor fails the test.

1. If the motor passes both of these tests and the shaft spins freely when rotated by hand, then the motor is ok and only the control must be replaced. Continue with replacing the ECM control module in step 5.
2. If the motor fails either of these tests or does not spin freely when rotated by hand, replace the motor and control modules following the guidelines on page 36. NOTE: The X13® motor is no longer available. Its direct replacement is the Endura® Pro. Endura Pro is an exact electrical and mechanical match to the X13. The correct replacement Endura Pro control module or motor and control module parts must be ordered from the manufacturer of the HVAC unit (furance, air handler, or package system) the motor was removed from.
3. Insert the 3-pin connector back into the new control module. A slight click will be heard when inserted properly. This connector is keyed for proper connection.
4. Attach the new control module with the plug connections oriented down (see figure 14), insert the appropriate bolts and tighten.
5. Reinstall the blower/motor assembly into the HVAC system by following the manufacturer’s guidelines.
6. Reconnect all wires and/or connectors. Make sure individual wires are connected to proper taps.
7. Be certain to form a drip loop so that water cannot enter the motor by draining down the cables (see Figure 14).
8. Go to the Final Installation Checks section.

Replacing the ECM Motor and Control Modules

For Endura^® Pro

1. The most efficient way to install the motor is to have the control already attached.
1. If the new motor and control are not already bolted together use the OEM instructions or steps 5 and 6 on page 34.
2. When replacing the X13 or Endura Pro motor with a belly band for mounting, the band should not be located in the area identified in Figure 15.
3. Before tightening down the belly band, rotate the motor until the connectors in the control are facing down or at least between the 4 and 8 o’clock position in the blower housing, as it will mount into the HVAC system (see figure 14 page 35).
4. Center the blower wheel in the blower housing and tighten the blower wheel hub bolt on the flat portion of the motor shaft.
5. Reinstall the blower/motor assembly into the HVAC system by following the manufacturer’s guidelines.
6. Reconnect all wires and/or connectors. Make sure individual wires are connected to proper taps.
7. Be certain to form a drip loop so that water cannot enter the motor by draining down the cables (see figure 14 above).
8. Go to the Final Installation Checks section.

Indoor Motor Final Installation Checks

• Check all wiring and connections, especially those removed while servicing.

Ensure the system is set up as follows:

• Clear all condensate drain and traps.
• Check and plug leaks in return ducts and equipment cabinet.
• Verify that the system is running quietly and smoothly, producing proper air flow in all modes (heating, cooling, and continuous fan) and all stages (if applicable).
• Return all thermostat settings to the customer’s preference.
• If any evidence of moisture, then correct the issue.
• If the area is subject to high amounts of lightning strikes, then use of additional transient protection may be helpful.

Additional Good Practices:

• Finish all service calls by checking all safeties and perform a visual inspection of the overall job to prevent call-backs.
• Check the level of Carbon Monoxide (CO) in the vent(s) and living spaces of all homes with fossil-fuel appliances.
• Recommend annual maintenance.