SiUS371901EB
Check
Part 6 Service Diagnosis
442
Warning
Warning
4.14 Fan Motor Connector Check for FXTQ-TA
CHECKING EMERSON ULTRATECH
TM
ECM MOTORS
The FXTQ-TA models utilize an Emerson, 4-wire variable speed ECM blower motor. The ECM
blower motor provides constant CFM.
The motor is a serially communicating variable speed motor. Only four wires are required to control
the motor: +Vdc, Common, Receive, and Transmit.
The +Vdc and Common wires provide power to the motor's low voltage control circuits.
General Checks / Considerations
Emerson UltraCheck-EZ
TM
Diagnostic Tool
The Emerson UltraCheck-EZ
TM
diagnostic tool may be used to diagnose the ECM motor.
HIGH VOLTAGE!
Disconnect ALL power before servicing or installing. Multiple power sources may be present.
Failure to do so may cause property damage, personal injury or death.
To use the diagnostic tool, perform the following steps:
Line Voltage now present.
CHECK 19
1.
Check power supply to the air handler or modular blower. Ensure power supply is within
the range specified on rating plate.
2.
Check motor power harness. Ensure wires are continuous and make good contact when
seated in the connectors. Repair or replace as needed.
3.
Check motor control harness. Ensure wires are continuous and make good contact when
seated in the connectors. Repair or replace as needed.
4.
Check blower wheel. Confirm wheel is properly seated on motor shaft. Set screw must
be on shaft flat and torqued to 165 in-lbs minimum. Confirm wheel has no broken or
loose blades. Repair or replace as needed.
5.
Ensure motor and wheel turn freely. Check for interference between wheel and housing
or wheel and motor. Repair or replace as needed.
6.
Check housing for cracks and/or corrosion. Repair or replace as needed.
7.
Check motor mounting bracket. Ensure mounting bracket is tightly secured to the
housing. Ensure bracket is not cracked or broken.
1.
Disconnect power to the air handler.
2.
Disconnect the 4-circuit control harness from the motor.
3.
Plug the 4-circuit connector from the diagnostic tool into the motor control connector.
4.
Connect one alligator clip from the diagnostic tool to a ground source.
5.
Connect the other alligator clip to a 24VAC source.
NOTE:
The alligator clips are NOT polarized.
NOTE:
The Ultra Check-EZ
TM
diagnostic tool is equipped with a non-replaceable fuse.
Connecting the tool to a source other than 24VAC could damage the tool and cause the
fuse to open. Doing so will render the diagnostic tool inoperable.
6.
Turn on power to air handler or modular blower.
Summary of Contents for REYQ72-432XAYCU
Page 455: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 448 REYQ144 168XATJU REYQ144 168XATJA 2D119206B ...
Page 457: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 450 REYQ144 168XAYDU REYQ144 168XAYDA 2D119208C ...
Page 461: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 454 FXZQ05 07 09 12 15 18TAVJU 3D110443A ...
Page 463: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 456 FXEQ07 09 12 15 18 24PVJU 3D098557A ...
Page 464: ...Wiring Diagrams SiUS371901EB 457 Part 7 Appendix FXDQ07 09 12 18 24MVJU C 3D050501C ...
Page 468: ...Wiring Diagrams SiUS371901EB 461 Part 7 Appendix FXHQ12 24 36MVJU 3D048116C ...
Page 469: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 462 FXAQ07 09 12 18 24PVJU 3D075354F ...
Page 475: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 468 VAM1200GVJU 3D073270D ...
Page 478: ...Wiring Diagrams SiUS371901EB 471 Part 7 Appendix BS6 8Q54TVJ 2D089122B ...
Page 479: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 472 BS10 12Q54TVJ 2D089121B ...
Page 481: ...SiUS371901EB Wiring Diagrams Part 7 Appendix 474 BSF6 8Q54TVJ 2D123905A ...