The manufacturer of a garage-door opener says owners should unplug the system immediately because it may open or shut without warning and may not reverse as it is designed to do if it hits a person or object.

The Stanley Electronic Division of Stanley Works announced a recall Monday of models made with defective circuit boards. The Stanley-made boards were used in openers produced under the brand names Stanley, Fimbel Power Lift and Fimbel EZ Lift.The openers were sold nationwide between Jan. 14 and April 11. Up to 5,000 may have been bought and installed, said Joseph Jones, president of Stanley Home Automation.

Because of the defective circuits, a safety feature that causes the door to reverse when it strikes something doesn't work, Jones said.

No injuries or accidents have been reported, Jones said. He said the company learned of the defect when consumers called to report problems.

"The one that we are very much the most concerned about is the door closing and not reversing," Jones said. "We're desperately trying to get them all back."

The affected Stanley openers carry date codes of 91-04-01 through 91-15-5. The Fimbel Power Lift and Fimbel EZ Lift openers have date codes of 01-21-91 through 04-11-91.