TROUBLESHOOTING INDOOR ECM™ 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.

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

Symptom Cause/Procedure

• “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

high CFM (speed)

Evidence of Moisture

Motor failure or malfunction has occurred and moisture is present

Evidence of moisture present inside air mover

“puffing”?

- Reduce restriction

- Reduce max. airflow

• Replace motor and Perform Moisture Check

Perform Moisture Check

• Check motor for tight shaft

• Perform motor/control replacement check

Perform Moisture Check

Do

• Check out motor, controls,

wiring and connections

thoroughly before replacing

Don’t

Automatically assume the motor is bad.

Motor rocks, but won’t start

Motor oscillates up

load & down while being tested off of blower

Motor starts, but runs erratically

Varies up and down or intermittent

Check for loose or compliant motor mount

Make sure blower wheel is tight on shaft

Perform motor/control replacement check

It is normal for motor to oscillate with no on shaft

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, Thermostat

Perform Moisture Check

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

• 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

• “Hunts” or “puffs” at

• Does removing panel or filter reduce

high CFM (speed)

“puffing”?

 

- Reduce restriction

 

- Reduce max airflow

• Size the equipment wisely

• Check orientation before

inserting motor connectors

Oversize system, then compensate with low airflow

Plug in power connector backwards

Force plugs

Moisture Check

Stays at low CFM despite system call for cool or heat CFM

Stays at high CFM

Blower won’t shut off

Check low voltage (Thermostat) 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

“R” missing/not connected at motor

Is fan in delay mode? - wait until delay time complete

Perform motor/control replacement check

Current leakage from controls into G, Y or W? Check for Triac switched thermostat or solid- state relay

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?

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

Manual

2100-549G

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Bard I42H1D, I36H1D, I60H1D, I48H1D, I30H1D installation instructions Troubleshooting Indoor ECM Blower Motors