Figure 14 Control Disassembly; Figure 15 Winding Test; Figure 16 Drip Loop - Bard CH4S1 Installation Instructions Manual

troubleshooting Ge ecm
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 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 not necessary to remove the motor from the blower assembly, nor
the blower assembly from the unit. Unplug the two cable connectors to the
motor control assembly. There are latches on each connector. Do Not
PuLL oN tHE wIRES. The plugs remove easily when properly released.
4. Locate the screws that retain to the motor control bracket to the sheet
metal of the unit and remove them. Remove two (2) nuts that retain
the control to the bracket and then remove two (2) nuts that retain sheet
metal motor control end plate. Refer to Figure 14.
5. Disconnect the three (3) wires interior of the motor control by using
your thumb and forefinger squeezing the latch tab and the opposite side
of the connector plug, gently pulling the connector. Do Not PuLL oN
tHE wIRES, gRIP tHE PLug oNLy. Refer to Figure 14.
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 15. (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.
Only remove
Hex Head Bolts
ECM 2.0
Note:
Use the shorter
bolts and
alignment pin
supplied when
replacing an
ECM 2.0
control.
Manual 2100-455M
Page 28 of 28
Figure 14
Figure 3
Control Disassembly
From Motor
Push until
Latch Seats
Over Ramp
Circuit
Board
Motor
Motor Connector
(3-pin)
ECM
Control Connector
2.3/2.5
(16-pin)
Power Connector
(5-pin)
Hex-head Screws
motors (cont'd.)
™
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.
8. Reverse the steps #5, 4, 3 to reconnect the motor control to the
motor wires, securing the motor control cover plate, mounting the
control to the bracket, and mounting the motor control bracket back
into the unit. 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. DO nOt
OvErtigHtEn tHE BOLtS.
9. Plug the 16-pin control plug into the motor. The plug is keyed.
Make sure the connector is properly seated and latched.
10. 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.
11. Final installation check. Make sure the motor is installed as follows:
a. Motor connectors should be oriented between the 4 o'clock
and 8 o'clock positions when the control is positioned in its
final location and orientation.
b. Add a drip loop to the cables so that water cannot enter the
motor by draining down the cables. Refer to Figure 16.
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 15
Figure 4
Winding Test
Motor Connector
(3-pin)
Figure 16
Figure 5
Drip Loop
Connector Orientation
Back of
Control
Between 4 and 8 o'clock
Drip Loop
Motor OK when
R > 100k ohm