Bard QW2S1, QW4S1, QW3S1, QW5S1 Troubleshooting GE ECM Motors CONT’D, Replacing ECM Control Module

TROUBLESHOOTING GE ECM™ MOTORS CONT’D.

Replacing ECM Control Module

To replace the control module for the GE variable-speed indoor blower motor you need to take the following steps:

1.You MUST have the correct replacement module. The controls are factory programmed for specific operating modes. Even though they look alike, different modules may have completely different functionality.

USING THE WRONG CONTROL MODULE VOIDS ALL PRODUCT WARRANTIES AND MAY PRODUCE UNEXPECTED RESULTS.

2.Begin by removing AC power from the furnace or air handler being serviced. DO NOT WORK ON THE MOTOR WITH AC POWER APPLIED. To avoid electric shock from the motor’s capacitors, disconnect power and wait at least 5 minutes before opening motor.

3.It is usually not necessary to remove the motor from the blower assembly. However, it is recommended that the whole blower assembly, with the motor, be removed from the furnace/air handler. (Follow the manufacturer’s procedures). Unplug the two cable connectors to the motor. There are latches on each connector. DO NOT PULL ON THE WIRES. The plugs remove easily when properly released.

4.Locate the two standard ¼" hex head bolts at the rear of the control housing (at the back end of the control opposite the shaft end). Refer to Figure 28. Remove these two bolts from the motor and control assembly while holding the motor in a way that will prevent the motor or control from falling when the bolts are removed. If an ECM2.0 control is being replaced (recognized by an aluminum casting rather that a deep-drawn black steel can housing the electronics), remove only the hex-head bolts. DO NOT REMOVE THE TORX-HEAD SCREWS.

5.The control module is now free of mechanical attachment to the motor endshield but is still connected by a plug and three wires inside the control. Carefully rotate the control to gain access to the plug at the control end of the wires. With thumb and forefinger, reach the latch holding the plug to the control and release it by squeezing the latch tab and the opposite side of the connector plug and gently pulling the plug out of the connector socket in the control. DO NOT PULL ON THE WIRES. GRIP THE PLUG ONLY.

6.The control module is now completely detached from the motor. Verify with a standard ohmmeter that the resistance from each motor lead (in the motor plug just removed) to the motor shell is >100K ohms. Refer to Figure 29. (Measure to unpainted motor end plate.) If any motor lead fails this test, do not proceed to install the control module.

THE MOTOR IS DEFECTIVE AND MUST BE REPLACED. Installing the new control module will cause it to fail also.

7.Verify that the replacement control is correct for your application. Refer to the manufacturer's authorized replacement list.

USING THE WRONG CONTROL WILL RESULT IN IMPROPER OR NO BLOWER OPERATION. Orient the control module so that the 3-wire motor plug can be inserted into the socket in the control. Carefully insert the plug and press it into the socket until it latches. A SLIGHT CLICK WILL BE HEARD WHEN PROPERLY INSERTED. Finish installing the replacement control per one of the three following paragraphs, 8a, 8b or 8c.

8a. IF REPLACING AN ECM 2.0 CONTROL (control in cast aluminum can with air vents on the back of the can) WITH AN ECM

2.3CONTROL (control containing black potting for water protection in black deep-drawn steel case with no vents in the bottom of the can), locate the two through-bolts and plastic tab that are packed with the replacement control. Insert the plastic tab into the slot at the perimeter of the open end of the can so that the pin is located on the inside of the perimeter of the can. Rotate the can so that the tab inserts into the tab locater hole in the endshield of the motor. Using the two through-bolts provided with the replacement control, reattach the can to the motor.

THE TWO THROUGH-BOLTS PROVIDED WITH THE REPLACEMENT ECM 2.3 CONTROL ARE SHORTER THAN THE BOLTS ORIGINALLY REMOVED FROM THE ECM 2.0 CONTROL AND MUST BE USED IF SECURE ATTACHMENT OF THE CONTROL TO THE MOTOR IS TO BE ACHIEVED. DO NOT OVERTIGHTEN THE BOLTS.

8b. IF REPLACING AN ECM 2.3 CONTROL WITH AN ECM

2.3CONTROL, the plastic tab and shorter through-bolts are not needed. The control can be oriented in two positions 180° apart.

MAKE SURE THE ORIENTATION YOU SELECT FOR REPLACING THE CONTROL ASSURES THE CONTROL'S CABLE CONNECTORS WILL BE LOCATED DOWNWARD IN THE APPLICATION SO THAT WATER CANNOT RUN DOWN THE CABLES AND INTO THE CONTROL. Simply orient the new control to the motor's endshield, insert bolts, and tighten. DO NOT OVERTIGHTEN THE BOLTS.

8c. IF REPLACING AN ECM 2.0 CONTROL WITH AN ECM

2.0CONTROL (It is recommended that ECM 2.3 controls be used for all replacements), the new control must be attached to the motor using through bolts identical to those removed with the original control. DO NOT OVERTIGHTEN THE BOLTS.

9.Reinstall the blower/motor assembly into the HVAC equipment. Follow the manufacturer's suggested procedures.

10.Plug the 16-pin control plug into the motor. The plug is keyed. Make sure the connector is properly seated and latched.

11.Plug the 5-pin power connector into the motor. Even though the plug is keyed, OBSERVE THE PROPER ORIENTATION. DO NOT FORCE THE CONNECTOR. It plugs in very easily when properly oriented. REVERSING THIS PLUG WILL CAUSE IMMEDIATE FAILURE OF THE CONTROL MODULE.

12.Final installation check. Make sure the motor is installed as follows:

a. Unit is as far INTO the blower housing as possible.

b.Belly bands are not on the control module or covering vent holes.

c. Motor connectors should be oriented between the 4 o’clock and 8 o’clock positions when the blower is positioned in its final location and orientation.

d.Add a drip loop to the cables so that water cannot enter the motor by draining down the cables. Refer to Figure 30.

The installation is now complete. Reapply the AC power to the HVAC equipment and verify that the new motor control module is working properly. Follow the manufacturer's procedures for disposition of the old control module.

		Figure 28		Figure 29
	Control Disassembly			Winding Test
			Motor Connector
Only remove		From Motor	(3-pin)
Hex Head Bolts	Push until
	Latch Seats
	Over Ramp
		Circuit
		Board
ECM 2.0		Motor
				Motor OK when
Note:				R > 100k ohm
Use the shorter
bolts and
alignment pin				Figure 30
supplied when
replacing an				Drip Loop
ECM 2.0		Motor Connector
control.				Connector Orientation
		(3-pin)	Back of
ECM			Control	Between 4 and 8 o'clock
2.3/2.5		Control Connector
		(16-pin)
		Power Connector
		(5-pin)
		Hex-head Screws		Drip Loop

Manual	2100-532B
Page	43 of 46