Manual 2100-586G
Page
24 of 25
Do’s and Dont’s
Do
Don’t
Check out motor, controls,
wiring and connections
thoroughly before
replacing motor
Automatically assume
motor is bad
Orient connectors down so
water can’t get in - Install
“drip loops”
Locate connectors above 8
and 4 o’clock positions
Use authorized motor and
model #s for replacement
Replace one motor or
control model # with
another (unless an
authorized replacement)
Keep static pressure to a
minimum:
- Recommend high
efficiency, low static
filters
- Recommend keeping
filters clean
- Design ductwork
for minimum static,
maximum comfort
- Look for and
recommend ductwork
improvement, where
necessary
Use high pressure drop
filters—some have ½"
H2O drop!
Use restricted returns
Size equipment wisely
Oversize system then
compensate with low
airflow
Check orientation before
inserting motor connectors
Plug in power connector
backwards
Force plug
Moisture Check
• Connectors are oriented “down” (or as
recommended by equipment manufacturer)
• Arrange harness with “drip loop” under
motor
• Is condensate drain plugged?
• Check for low airflow (too much latent
capacity)
• Check for undercharged condition
• Check and plug leaks in return ducts,
cabinet
Comfort Check
• Check proper airflow settings
• Low static pressure for lowest noise
• Thermostat in bad location?
Symptom
Cause/Procedure
Motor rocks slightly when
starting
This is normal start-up for ECM
Motor won’t start:
No movement
Check blower turns by hand
Check power at motor
Check low voltage (24 Vac R to C) at
motor
Check low voltage connections (G, 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
Perform
Moisture Check
Motor won’t start:
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 and 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 or down or intermittent
Check line voltage for variation or “sag”
Check low voltage connections (G, R, C)
at motor, unseated pins in motor harness
connectors
Check out system controls, thermostat
Perform
Moisture Check
Motor starts but runs erratically:
“Hunts” or “puffs”
Does removing panel or filter reduce
“puffing”?
- Reduce restriction
Motor starts but runs erratically:
Blower won’t shut off
Current leakage from controls into G, Y?
- Check for Triac-switched thermostat
or solid-state relay
Excessive noise
Determine if it’s air noise, cabinet, duct
or motor noise; interview customer, if
necessary
Excessive noise:
Air noise
High static creating high blower speed?
- Is airflow set properly?
- Does removing filter cause blower
to slow down? Check filter
- Use low-pressure drop filter
- Check/correct duct restrictions
Excessive noise:
Noisy blower or cabinet
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
Evidence of Moisture:
Motor failure or malfunction has
occurred and moisture is present
Replace motor and
Perform Moisture
Check
Evidence of Moisture:
Evidence of moisture present
inside air mover
Perform
Moisture Check
Troubleshooting ECM
TM
Indoor Blower Motors
CAUTION:
Disconnect power from unit before removing or replacing connectors, or servicing motor. To avoid electric
shock from the motor’s capacitors, disconnect power and wait at least 5 minutes before opening motor.
