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# Misaligned safety photocells: how do I adjust them?

Does your door refuse to close, or reopen on its own at the end of closing? The safety photocells are often the cause.
**What to check:**
* Alignment — the two photocells must be exactly facing each other.
* Cleanliness — dust or dirt on the lens can disrupt detection.
* The indicator light — shows whether the alignment is correct.
* An actual obstacle in the doorway.

Is adjusting the alignment not enough? Describe your door's exact behaviour to us: we'll identify whether the photocells need replacing.