Faulty burglar alarms can be annoying not only to the householder but neighbours and even passers-by.
Broken alarms also undermine the effectiveness of security systems as a deterrent again unwanted intruders.
Regularly sounding alarms not only annoy neighbours they promote the notion that a signal is always false and to be ignored rather than acted on.
There exist many things that trigger a false alarm and much depends on the system and its use.
However, engineers from Crown Securities UK are called out to scores of faulty alarms every month, and they find problems that are common to many systems.
Poor connections are a widespread cause of faulty alarm callouts and can be caused by erosion, improper use, water infiltration and a host of other sources. They are usually easy to fix, but the problem is finding them in the first place, especially in large and sophisticated security systems.
Worn out batteries are another common cause of security system failure. Wireless system, in particular, can be affected by degraded cells and this is a problem with systems that are not regularly checked and maintained.
Interference from animals, both domestic pets such as cats and wild animals such as mice or birds, is often behind faults in the security alarm network. This is often the case in units that are fixed outside or in roof spaces.
Degraded sensors are another source of problems for security system engineers, especially if they are poorly sited or badly fitted. Sensors are the 'eyes and ears' of any security alarm system, and it is vital that they are checked regularly and properly maintained.
Working knowledge of how burglar alarm systems are set up and the way that sensors operate can be a great help in understanding why a system is not functioning correctly and where any faults are most likely to occur.
Most security alarm systems consist of a control box and an array of sensors. The sensors can be of various types and connected to the control box in several ways, but the principle is the same; a controller in the control box runs a computer program that regularly checks the sensors and generates an alarm signal if it detects one or more sensors has been activated.
The importance of alarm sensors.
Sensors are electronic devices that can detect movement or sudden changes in light or temperature.
Sensors have microswitches which are typically closed and, if the sensors activate, the microswitch opens and the electric circuit is broken.
When this happens, the control box automatically triggers the alarm which may be an external bell or klaxon or an autodialer then posts a warning message.
Sensors can be of various types. Standard window and door sensors have switches that a kept closed by a small magnet. Some have shock sensors that can detect when glasses is smashed, or a door is forced. Room sensors have air units that detect body heat while microwave sensors are best at detecting movement and pressure mats are sensitive to someone stepping on them.
Central control boxes usually have a simple LED display and a keypad for entering commands or inputting passwords.
Some control boxes are hard-wired to sensors while others operate through radio signals or a local wi-fi network. The advantage of wireless control panels is that they can be hidden from view and can't be traced by following wires.
Smart security systems can be operated from mobile phones, computers or other devices and don't need a keypad.
Control boxes usually operate separate 'zones' that can be controlled independently. For example zone one might include exterior doors, zone two include downstairs window, zone three the internal doors and so on.
This way, zones can be automatically switched on and off as they are needed. At nighttime, external door sensors can be activated while internal PIR sensors are turned off so that getting out of bed doesn't trigger an alarm.
Security systems for large buildings and commercial properties can have very sophisticated zone alarm networks.
Most control boxes will also have tamper circuits to detect unauthorised interference with security systems, even when they are not active.
They will all also usually have backup battery power units to cover mains power outages, and external bells or klaxons may also have backup battery power units.
Many hard-wired wired alarm networks use a six core cable. One pair of core wires are used for the sensor circuit; another is for switching system with the remaining couple are used for the tamper circuit.
Microswitches in a tamper circuit usually are closed, allowing the electric current to run. If someone tampers with the system, for example removing a cover or cutting the wire, the switches are thrown and the circuit is broken.
If your security alarm goes off when nothing is wrong, then the sensible thing is to switch it off. The problem is that many alarms are tamper-proof and have backup batteries or built-in systems that override a simple switch off. After all, if you can turn off the system then so can an intruder.
DIY repairs can also be inadvisable as control panels often operate on mains electricity and, without proper knowledge of the system, messing with the main can have shocking results.
External bells and sirens may also be connected directly to main supplies even when they appear to be inactive.
If you have a faulty alarm, especially if it is breaking down regularly, we strongly advise you call in the experts to fix it.
Crown Securities UK operates a 24-hour emergency call-out service every day of the year, even Bank Holidays, for security alarm systems across the Midlands, North West, North Wales and Manchester.
Call us for free day or night on 0800 019 1131 and an expert engineer can be with you in under an hour, although time will depend on location.
Our engineer only needs your name, address, postcode and any information you can give about the fault. We may also record telephone calls for verification and training purposes and any data we may collect is considered private and handled in full compliance with Data Protection laws and regulations.
We regret we cannot advise how to disable your burglar alarm over the telephone due to health, safety and crime prevention issues.
Our emergency call-out engineer will attend promptly and ensure the alarm is silenced to avoid nuisance or annoyance and carry out an investigation of the fault.
Technicians carry an extensive range of spare parts and can try to reinstate your alarm system to full proper working order. Where this is not possible, your system will be safely shut down, and you can arrange a visit to repair the problem later.
All work carried out by our technical team is guaranteed and following the repair you will receive a written report outlining all the repair work carried out and a VAT receipt for any payment made.