Table of Contents
Advertisement
Replacing ECM Control Module
To replace the control module for the GE variable-speed indoor blower
motor, take the following steps:
1.
It is essential to 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 unit 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 unit. (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). See 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 ECM 2.0 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. See 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 the 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.
8.
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 selected 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.
Re-install 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 (see 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
2100-646
Page
21 of 26
Advertisement
Table of Contents
