The internal laser, which is fitted to two of the current beam smoke detectors in the Fireray range is primarily used for alignment. However, it also play's a major role in fault finding.
Once aligned, if the beam smoke detector is not mounted to a solid surface or structure (see other Blogs), it can go out of alignment due to building movement.
Problems like this cannot always be easy for an engineer to either solve or identify, but one thing you can do to check if the beam smoke detector has moved since commissioning or the last service visit is to use the laser.
The Fireray 3000 and Fireray 5000 beam smoke detector both have internal lasers. With the Fireray 3000, the laser in the receiver is manually steered onto the transmitter and then the beam is aligned at the transmitter end. Once this has been done, the laser should not move off the Transmitter. If it does, this could be due to the fact that the receiver’s mounting has moved due to building movement or the receiver has been ‘knocked’ out of alignment. Also, if the laser is not on the transmitter, it could also be due to the fact that the transmitter’s mounting has been moved, again due to building movement or it has been knocked out of alignment.
With the Fireray 5000, the laser is steered onto the reflector(s) using the buttons on the system controller. Once this has been done, the beam is aligned using the ‘Auto’ function and the engineer can note where the laser is on the wall where the reflector is mounted. Please note that the laser is not always 100% in parallel with the Infra-Red signal, as the laser is only a guide to get the Infra-Red signal onto the reflector so alignment can take place. After alignment, the laser will not usually be where it was before alignment. This does not matter, what does matter is it should not move from that spot after alignment. If it does, this can indicate movement at the detector or reflector end. Again, please note, the Detector head can re-align itself after its internal compensation level (AGC-Automatic Gain Control) reaches a certain level. However, this will also indicate that there are changes to the original alignment conditions such as a build-up of dust or building movement.
So, to sum up, if there are unexplained activations due to suspected building movement from the Fireray 3000 or Fireray 5000. Try using the techniques described above as an additional fault finding aid.