Why does a bent louver actuator crank arm lock the blades?

Field answer

If an actuator hums but the blades stay frozen, the problem may be linkage alignment, a bent crank arm, a jammed torque bar, or frame distortion—not the controls alone.

Disconnect power/control as required, manually verify blade travel, and inspect the linkage. Replace bent hardware or reseat the linkage on the proper flat/shaft position, then cycle the actuator only after the blades move freely.

What to check first

• Confirm the actuator voltage/control signal only after checking mechanical bind.
• Disconnect linkage and move blades by hand if allowed.
• Inspect crank arm, set screw, torque bar, and blade linkage.
• Check if long screws or frame distortion are jamming tracks.
• Cycle fully open/closed before final signoff.

Why it matters

A bound actuator can burn out and leave the intake/exhaust stuck shut or open.

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