This is a very common question, as our QFM330 wall mounted monitor is powered by batteries (mains version is available as an option). We designed the unit to be battery powered because we found that users would tend to fit monitors near to the mains supply, rather than in the ideal safety location. A second reason was that in the event of a mains failure, unless a battery backup system was fitted, the unit would not function.
Typical back up systems only last for a few hours in alarm, whereas the Quantum QFM330 will last in alarm for several weeks, providing much better protection. The unit incorporates a low battery indication/alarm so the user is not at risk from battery failure. The QFM330 monitor is powered via batteries that only have to be changed every two years at the same time as the sensor. The replacement QM330RS sensor/battery, is a single pack that houses both the sensor and batteries. Fitting the new sensor/battery pack is easily undertaken by the user.
When we fit larger systems, the power is supplied via the main control panel. In the event that a cable is cut, or the main control panel is switched off, the monitor will sense the loss of the supply voltage and switch to its internal battery, so as to ensure continuous protection for the user. (2 year life from new). Our new version of the wall mounted monitor, available in June 2014, will also have the facility of connecting an external voltage (12V) as standard. In the event that the user fits this supply, the monitor will be powered via the mains low voltage supply. However, in the event that the mains supply fails the monitor will automatically switch to its own internal supply. This will be a standard function of the new monitor.