Troubleshooting Guide

WARNING: Troubleshooting and repairs should be completed by a qualified technician or licensed electrician. Failure to follow safe guidelines can result in injury or death. Power to the door should be disconnected prior to attempting any repair.

Motor Will Not Run

No Power

  • Power not connected to building
  • Replace circuit breaker or fuse
  • Break in wire

Reset Button Tripped

  • Push reset button

Loose Electrical Connection

WARNING: Disconnect power before inspecting any electrical connection. Failure to do so can result in electrocution and death.

  • Disconnect power and open control box.
  • Tighten all screws on the white and black part of the contact
  • Inspect and test all fuses, replace if bad
  • Check that there are 24 volts coming out of the secondary side of the transformer

Defective Motor Capacitor

  •  Inspect/replace start or run capacitor

External Top Override or Safety Switch

  • Ensure nothing is making contact with switch
  • Replace if bad switch

Power Source: Permanent or Temporary

If Temporary: Generator must be a minimum of 10,000 watts and wire must be sized to provide adequate voltage to control box.

If Permanent: Ensure correct voltage for operator and proper wire size from panel to control box.

Safety Switch On Latches

  • Latch must be fully disengaged
  • Latch handle must be making contact with limit switch

Push Button

  • Check that there are 24 volts at the push button
  • If not, see if a wire is pinched or cut
  • If not, see if there are 24 volts at terminals 1, 2 and 4

Motor Wired Wrong

  • Check wiring in motor

Motor Hums But Door Does Not Move


  • Ensure proper voltage at the control box

Brake Does Not Release

  • Check that voltage corresponds to that listed on the name plate
  • Check for incorrect wiring or broken wires
  • Check for a burned out coil and, if appropriate, replace magnet assembly

Motor Defective

  • Inspect and replace start and run capacitor, as necessary
  • Replace motor if windings are bad

Latches Engaged

  • Disconnect both latches

Motor Sprocket Set Screw Loose or Broken Away

  • Tighten set screw
  • Replace keyway

Motor Runs But is Noisy


  • Check for proper voltage into control box; inadequate voltage can cause motor contacts to chatter

Operator Rattles

  • If the brake vibrates, check solenoid contacts and voltage
  • If the sheaves are loose, tighten the cable sheaves on the top operator

Bad Cable Wind

  • Cable drum not properly aligned
  • Cable attached to drum incorrectly
  • Door closed on object: open door, remove object and re-align cable
  • Less than one wrap on drum: ensure there is more than one wrap around drum when door is closed

Cable Sheave Worn One Side More Than the Other

  • Sheave is out of alignment

Brake Chatters or Hums

  • Wrong voltage supply
  • Dirty magnet faces — to remove dirt, insert a clean sheet of paper between faces and energize brake while moving paper between faces to dislodge dirt, and then remove paper
  • Loose or broken shading coil — replace magnet assembly

Brake Not Releasing

  • Check wire
  • Ensure there’s adequate voltage

Operator Makes a Clicking Noise

  • Chain and sprocket out of alignment
  • Worn sprocket

Operator Makes Thumping Noise

  • Belt damaged

Belt Rolls on Back Side

  • Sheave is out of alignment

Door Does Not Stop Properly or Inconsistently Stops

Brake Does Not Stop Properly

  • Brake is manually released
  • Worn friction disc: replace disc if worn to 1/8-inch thickness
  • If disc replacement is not required, adjust air gap

Limit Switches Not Set

  • Reset limit switches inside control box. Ensure limit shaft sprocket set screw is tight.

Manual Release on Brake Does Not Work

  • Improper setting
  • Broken or damaged parts

Limit Switches Not Working

  • Verify limit switch is not faulty
  • Ensure wires are connected to the correct switch

Door Lifting Improperly

Door Jumps

Bottom roller not turning

  • Rubbing against side rail
  • Roller bearing bad – replace roller bearing

Cable not feeding properly on top operator

  • Cable fell off sheave
  • Sheave not turning

Bottom Follower Roller Binding

  • Rubbing against i-beam
  • Adjust location of travel
  • Replace bearing

Door Lifting Crooked

Cable wrapped up over itself on drum

  • Adjust cable so wraps lay flat beside each other when winding

Nylon Strap Loose

  • Ensure all straps are tightened similarly

Motor Will Not Start Under Load

Low Voltage

  • Increase wire size to operator
  • Do not operate door off of generator producing less than 10,000 watts

Brake Not Releasing

  • Check for correct voltage
  • Check for low voltage

No Oil or Wrong Oil in Gearbox

  • Fill gearbox with oil
  • Use synthetic lube rated for appropriate temperatures

Door Difficult to Latch or Will Not Latch Shut

Bottom Rollers Resting on Ground, Snow/Ice or Debris

  • Clear debris from roller path

Bottom Limit Not Set Correctly

  • Reset bottom limit switch – ensure limit sprocket set screw is tight

Latch Cable Broken

  • Repair latch cable

Other Doors or Windows Open in Building Causing Bi-Fold to Blow Outward

  • Close other doors and windows

Sheaves Out of Alignment on Top Operator

  • Realign sheaves and cable

Gap in Center of Door When Closed

Bottom Rollers Affected

  • Ensure door is not closed on object and roller is free of debris

Latch Cable Broken

  • Repair latch cable

Turnbuckles Loose

  • Tighten turnbuckles on latch cable system
  • If unable to seal gap with turnbuckles, the timing will need to be adjusted