TROUBLESHOOTING ECM BLOWER MOTORS
CAUTION
Disconnect power from unit before removing or replacing connectors, or servicing motor. Wait at least 5 minutes after disconnection power before opening motor.
SYMPTOM
Motor rocks slightly when starting.
Motor won't start
%No movement
%Motor rocks, but wo'nt start
Motor oscillates up and down while being tested off of blower
%Noisy blower of cabinet
%"Hunts" or "puffs" at high CFM (speed)
Evidence of Moisture
CAUSE / PROCEDURE
%This is normal
%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
%Run Mositure Check
%Check for loose or compliant motor mount
%Make sure blower wheel is tight on shaft
%It is normal for motor to oscillate with no load on shaft.
%Check for loose blower housing, panels, etc.
%High static creating high blower speed?
–Check for air whistling through seams in ducts, cabinets or panels.
–Check for cabinet / duct deformation
%Does removing panel or filter reduce "puffing"?
–Reduce restiction
–Reduce maximum airflow
% Motor failure of malfunction has occured and | % | Replace motor and perform Moisture Check | |
% | moisture is present | % | Perform Moisture Check |
Evidence of moisture present inside air mover | |||
DO |
| DON'T | |
% | Check out motor, controls, wiring and connections | % | Automatically assume the motor is bad |
| thoroughly before replacing motor |
|
|
% | Orient connectors down so water ca'nt get in; | % Locate connectors above 7 and 4 o'closk postions | |
install "drip loops"
%Use authorized motor and control model numbers % Replace one motor of control model number with another
for replacement |
| (unless an authorized replacement) |
% Keep static pressure to a minimum: | % | Use high pressure drop filters. Some have 1/2" H O drop! |
|
| 2 |
– Recommend high efficiency, low static filters | % | Use restricted returns |
–Recommend keeping filters clean
–Design duct work for minimum static, maximum comfort
–Look for and recommend duct work improvement,where necessary, in replacement.
Manual
Page 22
