CAUSE
- Loose or broken coupling (belt drive)
- Loose set screws on wheel hubs
- Fan spinning inside fan housing
- Broken fan hub
- Bearing end caps worn
- Damaged blower wheel
- Bearing end caps worn
- Balancing clips missing
SOLUTION
- Replace or tighten coupling
- Tighten set screws on motor shaft flats
- Tighten fan on shaft or replace fan
- Replace fan wheels
- Replace Bearing end caps
- Replace Blower Wheel
- Replace Bearing end caps
- Replace Blower Wheel
Air Curtain FAQ & Troubleshooting Guide
Troubleshooting Guide
Unheated Models
Excessive Noise And Or Vibration
No Air Blowing out of Discharge Nozzle
CAUSE
- No power being supplied to the unit from the electrical power source
- Circuit breaker is tripped
- Blown fuses on power supply
- Motor overload is open or tripped
- Motor contactor / relay defective (if applicable)
- Failed switch
SOLUTION
- Confirm power source / check if in on position
- Reset circuit breaker
- Replace fuses
- Allow the motor to cool down; motor has auto reset internal overload; if unit is panel equiped, press reset button on overload inside panel, or replace motor overload if overload remains tripped
- Check voltage to coil; check contacts to see if they are pulling in (see voltage reading chart).
- Replace or repair limit switch (see switch OIP)
Motor Is Running But Fans Are Not Spinning
CAUSE
- Loose or broken coupling (belt drive)
- Loose set screws on wheel hubs
- Fan spinning inside fan housing
- Broken fan hub
SOLUTION
- Replace or tighten coupling
- Tighten set screws on motor shaft flats
- Tighten fan on shaft or replace fan
- Replace fan wheels
Electrical Controls Not Working When Door Is Open
CAUSE
- Switch is in off position
- Door limit switch is not operating
SOLUTION
- Turn unit's switch to the on position
- Repair or replace door limit switch (see switch OIP)
Unit Will Not Turn Off
CAUSE
- Door limit switch is permanently closed or energized
SOLUTION
- 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
CAUSE
- Discharge air vanes out of adjustment
- Obstuction on intake or discharge
- Power leads out of polarity
- Blower motor rotating below normal speed
- Fan rubbing against housing
- Blower wheels clogged with dirt
SOLUTION
- Adjust vanes to proper position (Refer to unit's O&M manual)
- Remove obstuction or move air curtain
- Switch power leads to correct polarity (3 phase models only)
- Apply proper voltage per unit requirement (see unit label) / Adjust adjustable motor speed knob (if applicable)
- Free fan from housing
- Clean and remove dirt from blower wheels
Excessive Air Velocity At Door Opening
CAUSE
- Nozzle out of adjustment and not angled far out enough
- Air temperature too cold
- Air stream pushing air outside of the building
** SEE AIR IS NOT HITTING THE FLOOR FOR FURTHER CAUSES
SOLUTION
- Adjust nozzle angle to outside
- Add auxilary heat to overcome wind chill
- Adjust discharge angle back into building
Air Not Hitting The Floor
CAUSE
- Low air velocity
- Obstuction in the direction of air flow
- Negative building pressure
SOLUTION
- Adjust vanes to proper position or check installation height (Refer to O&M manual)
- Remove obstuction or move air curtain (Move out 3/8" for every 1" up from the door)
- Provide a make-up air system to relieve negative building pressure
Uneven Air
CAUSE
- Shaft rotating inside fan
- One motor not functioning
SOLUTION
- Replace fan or tighten fan on shaft
- Replace or repair motor
Electric Heated Models
No Heat
CAUSE
- Thermal overload stuck open or tripped
- Switch is in "Heat" mode
- Thermostat out of adjustment
- Defective coils
SOLUTION
- Replace thermal overload or reset overload
- Check wiring or replace switch
- Adjust thermostat and check t-stat wiring
- Replace coils / fix air flow issue
