Bard QW242D Installation Instructions Manual Download

Page: 46 / 49

Manual 2100-418F
Page

46 of 49

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 29.

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 30.

(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

2.3 CONTROL

(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

2.3 CONTROL

, 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.

NOT OVERTIGHTEN THE BOLTS.

8c.

IF REPLACING AN ECM 2.0 CONTROL WITH AN ECM

2.0 CONTROL

(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.

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 8o’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 31.

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.

Motor

Motor OK when

R > 100k ohm

ECM 2.0

Only remove

Hex Head Bolts

Connector Orientation

Between 4 and 8 o'clock

Drip Loop

Back of

Control

Figure 5