SiUS371901E
Check
Service Diagnosis
396
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
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.
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:
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 UltraCheck-EZ
TM
diagnostic tool is equipped with a nonreplaceable 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.
Line Voltage now present.
7. Depress the orange power button on the diagnostic tool to send a run signal to the motor. Allow
up to 5 seconds for the motor to start.
NOTE
: If the orange power button does not illuminate when depressed, the tool either has an
open fuse or is not properly connected to a 24VAC source.
8. The green LED on the diagnostic tool will blink indicating communications between the tool and
motor. See table below for indications of tool indicators and motor actions. Replace or repair as
needed.
CHECK 19
Warning
Warning
Summary of Contents for REYQ-XA
Page 1: ...Service Manual SiUS371901E REYQ72 456XATJU REYQ72 456XAYDU REYQ72 432XAYCU Heat Recovery 60 Hz...
Page 415: ...SiUS371901E Wiring Diagrams Appendix 402 REYQ144 168XATJU 2D119206A...
Page 416: ...Wiring Diagrams SiUS371901E 403 Appendix REYQ72 96 120XAYDU 2D119207B...
Page 417: ...SiUS371901E Wiring Diagrams Appendix 404 REYQ144 168XAYDU 2D119208B...
Page 418: ...Wiring Diagrams SiUS371901E 405 Appendix REYQ72 96 120 144 168XAYCU 2D119209A...
Page 421: ...SiUS371901E Wiring Diagrams Appendix 408 FXZQ05 07 09 12 15 18TAVJU 3D110443A...
Page 423: ...SiUS371901E Wiring Diagrams Appendix 410 FXEQ07 09 12 15 18 24PVJU 3D098557A...
Page 425: ...SiUS371901E Wiring Diagrams Appendix 412 FXSQ05 07 09 12 15 18 24 30 36 48 54TAVJU C 3D110467C...
Page 426: ...Wiring Diagrams SiUS371901E 413 Appendix FXMQ07 09 12 15 18 24 30 36 48 54PBVJU 3D093209B...
Page 428: ...Wiring Diagrams SiUS371901E 415 Appendix FXHQ12 24 36MVJU 3D048116C...
Page 429: ...SiUS371901E Wiring Diagrams Appendix 416 FXAQ07 09 12 18 24PVJU C 3D075354D...
Page 435: ...SiUS371901E Wiring Diagrams Appendix 422 VAM1200GVJU 3D073270D...
Page 437: ...SiUS371901E Wiring Diagrams Appendix 424 1 4 2 Multi Branch Selector Unit BS4Q54TVJ 3D089123B...
Page 438: ...Wiring Diagrams SiUS371901E 425 Appendix BS6 8Q54TVJ 2D089122B...
Page 439: ...SiUS371901E Wiring Diagrams Appendix 426 BS10 12Q54TVJ 2D089121B...
Page 440: ...Revision History Month Year Version Revised contents 04 2019 SiUS371901E First edition...
