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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 9. 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 10. (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. DO 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. 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 11.
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 9
Figure 10
Figure 11
Manual 2100-526H
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