Door Sensor Ignoring Your Door? We'll Get Detection Working Again in Smethwick

Door sensors are the workhorses of a home alarm — the small contact pairs fitted to doors that tell the panel when a door opens. When one stops detecting, the failure can be obvious (the alarm never reacts when you open the door) or sneaky (the zone shows as open all the time, or the alarm refuses to set because it thinks a door is ajar). Either way, a door contact that cannot be trusted needs attention, because entrance doors are exactly where you most want reliable detection. The causes are nearly always physical and findable: that is the reassuring part, and it is what our visit is built around.

Why a door contact stops detecting

The most common cause is separation. A contact sensor works as a pair — a switch on the frame and a magnet on the door — and they only register a closed door when the two halves sit close together. If the door has dropped on its hinges, swollen with damp, or the sensor has been knocked, the gap can grow past the sensor's tolerance and the panel reads the door as permanently open, or misses movement entirely. Damaged or missing magnets happen after a door is painted, planed or re-hung. On wireless contacts, a flat battery is extremely common and often produces exactly this behaviour. On wired contacts, a broken or chafed cable in the door frame is a classic culprit, as is a failed reed switch inside the sensor. Tamper switches can also stick after a sensor has been opened, leaving a zone fault on the panel that stops the system setting at all.

How we diagnose it

We start by observing the fault live: does the panel register the door opening and closing, does the zone show as open constantly, or is it intermittent? That distinction narrows things quickly. We then check the magnet and sensor alignment and the gap between them, inspect the door for drop or swelling, test the battery on a wireless contact and the wiring on a wired one, and check the tamper circuit. Where the panel supports it we use its own zone diagnostics, which tell us far more than guesswork. By the end of the visit you will know whether this is an alignment fix, a battery, a cable or a failed contact — and what each would cost.

Repairs and replacements

Alignment problems are usually fixed by re-mounting or re-positioning the sensor or magnet, adding the right spacer for a door that cannot close fully, or re-fixing a sensor that has worked loose — always with fixings suited to the frame material. Batteries are replaced as routine. A failed reed switch or damaged cable generally means replacing the contact or re-routing the cable, and we quote parts separately so you can decide with the numbers in front of you. If we find the real problem is the door itself dropping on its hinges, we will tell you, because fixing the sensor without addressing a door that keeps moving is a repair that will not last.

Honest expectations

A correctly fitted contact should detect its door reliably every time — but we will not claim any sensor suits every door and frame combination, and heavy, warped or rarely-used doors sometimes need a different sensor type. If so, we will say what we recommend and quote it separately. What we never do is leave a door zone bypassed as the solution.

Booking your visit

Call or book through the website and tell us which door is affected, whether the panel shows the zone as open or faulty, and whether the door has recently been painted, adjusted or dropped. You pay a booking fee when you book, labour is charged hourly at a rate that depends on how soon you need the visit, and the full cost is quoted and approved before work starts, with any parts quoted separately.