Thermo Pride Gas/Propane Furnace ECM CHX1 - Manual (Page 8)

All installations and services must be performed by qualified service personnel.
6
III. ECM TROUBLE SHOOTING
A. 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,Y,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,Y,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?
Check for Triac switched t’stat or solid state relay
Excessive noise
•
Determine if it’s air noise, cabinet, duct or motor
noise – interview customer, if necessary
•
Noisy blower or cabinet
•
Check for loose blower housing, panels, etc.
•
High static creating high blower speed?
! Check for air whistling thru seams in ducts,
cabinets or panels
! Check for cabinet/duct deformation