All installations and services must be performed by qualified service personnel.
14
The red Board Status LED has two functions:
It will light when the board recognizes a valid input signal and will stay lit until all valid signals are removed.
This is intended to show that the board is functioning and able to respond to input signals.
It will flash rapidly while120VAC is missing from the LIMIT switch. This is intended to give a quick visual
indication of the High LIMIT switch.
B. GENERAL GUIDELINES TO TROUBLESHOOTING GE ECM – DRIVEN SYSTEMS
:
Disconnect power from unit before removing or replacing connectors, or servicing motor.
Wait at least 5 minutes after disconnecting power before opening motor.
SYMPTOM
CAUSE/PROCEDURE
Motor rocks slightly when starting
This is normal start-up for ECM
Motor won’t start
No movement
Check power at motor
Check low voltage (24 VAC R to C) at motor
Check low voltage connections
(G,PWM,W,R,C,) at motor
Check for unseated pins in connectors on motor
harness
Test with a temporary jumper between R – G
Check motor for tight shaft
Perform motor/control replacement check
Run
Moisture Check
Motor rocks, but won’t start
Check for loose or compliant motor mount
Make sure blower wheel is tight on shaft
Perform motor/control replacement check
Motor oscillates up & down while being tested off
of blower
It is normal for motor to oscillate with no load on
shaft.
Motor starts, but runs erratically
Varies up and down or intermittent
Check line voltage for variation or “sag”
Check low voltage connections
(G,PWM,W,R,C,) at motor, unseated pins in
motor harness connectors
Check “Bk” for erratic CFM command (in
variable speed applications)
Check-out system controls – T’stat?
Perform Moisture Check
“Hunts” or “puffs” at high CFM (speed)
Does removing panel or filter reduce “puffing”?
Reduce restriction
Reduce max airflow
Stays at low CFM despite system call for cool or
heat CFM
Check low voltage (T’stat) wires and connections
Verify fan is not in delay mode – wait until delay
complete
“R” missing/not connected at motor
Perform motor/control replacement check
Stays at high CFM
“R” missing/not connected at motor
Is fan in delay mode? – wait until delay time
complete
Perform motor/control replacement check
Blower won’t shut off
Current leakage from controls into G,Y or W?
