PROBLEM
CAUSE
SOLUTION
NO AIR BLOWING
OUT OF DISCHARGE
NOZZLE
- No power being supplied to the unit
from the electrical power source
- Confirm power source / check if in on position
- Circuit breaker is tripped
- Reset circuit breaker
- Blown fuses on power supply
- Replace fuses
- Motor overload is open or tripped
- Allow the motor to cool down; motor has auto reset
internal overload; if unit is panel equipped, press
reset button on overload inside panel, or replace
motor overload if overload remains tripped
- Motor contactor / relay defective
(if applicable)
- Check voltage to coil; check contacts to see if they
are pulling in
- Failed switch
- Replace or repair limit switch
MOTOR IS RUNNING
BUT FANS ARE NOT
SPINNING
- Loose or broken coupling (belt drive)
- Replace or tighten coupling
- Loose set screws on wheel hubs
- Tighten set screws on motor shaft flats
- Fan spinning inside fan housing
- Tighten fan on shaft or replace fan
- Broken fan hub
- Replace fan wheels
ELECTRICAL
CONTROLS NOT
WORKING WHEN
DOOR IS OPEN
- Switch is in off position
- Turn unit's switch to the on position
- Door limit switch is not operating
- Repair or replace door limit switch
UNIT WILL NOT TURN
OFF
- Door limit switch is permanently
closed or energized
- Position the door switch in a manner that turns off the
unit when the door closes and turns on the unit when
the door opens. Only light pressure required.
LOW AIR FLOW
- Discharge air vanes out of
adjustment
- Adjust vanes to proper position
(Refer to Start-Up Section in this manual)
- Obstruction on intake or discharge
- Remove obstruction or move air curtain
- Power leads out of polarity
- Switch power leads to correct polarity
(3 phase models only)
- Blower motor rotating below normal
speed
- Apply proper voltage per unit requirement
(see unit label) / Adjust adjustable motor speed knob
(if applicable)
- Fan rubbing against housing
- Free fan from housing
- Blower wheels clogged with dirt
- Clean and remove dirt from blower wheels
EXCESSIVE AIR
VELOCITY AT DOOR
OPENING
- Nozzle out of adjustment and not
angled far out enough (BD only)
- Adjust nozzle angle to outside
- Air temperature too cold
- Add auxiliary heat to overcome wind chill
- Air stream pushing air outside of the
building
- Adjust discharge angle back into building
AIR NOT HITTING
THE FLOOR
- Low air velocity
- Adjust vanes to proper position or check installation
height (Refer to Start-Up Section in this manual)
- Obstruction in the direction of air flow
- Remove obstruction or move air curtain
(Move out 3/8" for every 1" up from the door)
- Negative building pressure
- Provide a make-up air system to relieve negative
building pressure
UNEVEN AIR
- Shaft rotating inside fan
- Replace fan or tighten fan on shaft
- One motor not functioning
- Replace or repair motor
EXCESSIVE NOISE
AND OR VIBRATION
- Loose or broken coupling (belt drive)
- Replace or tighten coupling
- Loose set screws on wheel hubs
- Tighten set screws on motor shaft flats
- Fan spinning inside fan housing
- Tighten fan on shaft or replace fan
- Broken fan hub
- Replace fan wheels
- Bearing end caps worn
- Replace Bearing end caps
- Damaged blower wheel
- Replace Blower Wheel
- Bearing end caps worn
- Replace Bearing end caps
- Balancing clips missing
- Replace Blower Wheel
TROUBLESHOOTING
