Bard Q48A1, Q30A1, Q36A1, Q42A1, Q60A1, Q24A1 Troubleshooting GE ECM Motors, Don’t

TROUBLESHOOTING GE ECM™ 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.

Symptom Cause/Procedure

Symptom Cause/Procedure

•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

•“Hunts” or “puffs” at • Does removing panel or filter reduce

Motor rocks slightly when starting

Motor won’t start

• No movement

• This is normal start-up for ECM

• Check blower turns by hand

• 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

high CFM (speed)	“puffing”?
	- Reduce restriction
	- Reduce max. airflow
Evidence of Moisture
• Motor failure or	• Replace motor and Perform Moisture Check
malfunction has occurred
and moisture is present
• Evidence of moisture	• Perform Moisture Check
present inside air mover
Do	Don’t

• Perform motor/control replacement check

• Perform Moisture Check

• Check out motor, controls,

wiring and connections

thoroughly before replacing

• Automatically assume the motor is bad.

• Motor rocks,	• Check for loose or compliant motor mount
but won’t start	• Make sure blower wheel is tight on shaft
	• Perform motor/control replacement check
Motor oscillates up	• It is normal for motor to oscillate with no load
& down while being	on shaft
tested off of blower
Motor starts, but
runs erratically
• Varies up and down	• Check line voltage for variation or “sag”
or intermittent	• 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, Thermostat
	• Perform Moisture Check
• “Hunts” or “puffs” at	• Does removing panel or filter reduce
high CFM (speed)	“puffing”?
	- Reduce restriction
	- Reduce max airflow

motor

• Orient connectors down so

water can’t get in

- Install “drip loops”

• Use authorized motor and

model #’s for replacement

• Keep static pressure to a

minimum:

- Recommend high

efficiency, low static filters

- Recommend keeping filters

clean.

- Design ductwork for min.

static, max. comfort

- Look for and recommend

ductwork improvement,

where necessary

• Size the equipment wisely

• Check orientation before

inserting motor connectors

• Locate connectors above 7 and 4 o’clock

positions

• Replace one motor or control model # with

another (unless an authorized replacement)

• Use high pressure drop filters some have ½"

H20 drop!

• Use restricted returns

•Oversize system, then compensate with low airflow

•Plug in power connector backwards

•Force plugs

• Stays at low CFM	• Check low voltage (Thermostat) wires and
despite system call	connections
for cool or heat CFM	• 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 thermostat or solid-
	state relay
Excessive noise	• Determine if it’s air noise, cabinet, duct or
	motor noise; interview customer, if necessary
• 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

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

•Set low continuous-fan CFM

•Use humidistat and 2-speed cooling units

•Use zoning controls designed for ECM that regulate CFM

•Thermostat in bad location?

Manual	2100-522B
Page	35 of 38