2. The "Fire" Led is on.

1. Has there been a 'Fire' condition?
2. Has the 'Fire' relay latched on, (after a 'Fire' condition has been present) and not reset (auto-reset off)?
3. Is something partially blocking the beam to create a fire condition?
4. Has the threshold been set to 25% in a dirty environment (too sensitive)?
5. Has the transmitter and/or receiver head been moved slightly after alignment has been carried out?
6. Has the 'signal level' potentiometer been moved after alignment has been carried out (anti-clockwise)?
7. Has the transmitter power been reduced after alignment has been carried out?
8. Has the lens of the Tx or Rx become dirty (therefore reducing the signal)?

1. The 'Trouble' or 'Fault' Led is on.

1. Is the beam path being blocked?
2. Has the power supply voltage dropped to below the required limit?
3. Is the mode switch in prism targeting mode?
4. Has the prism fallen off the wall?
5. Has the beam been moved when the mode switch was being placed into operating mode?

2. The 'Trouble' or 'Fault' Led is flashing.

1. The AGC limit has been exceeded (dirty lenses/poor alignment).
2. Is the mode switch in Prism targeting mode and the unit not been aligned correctly (partially seeing the prism)?

3. The 'Fire' Led is on

1. Is there a 'Fire' condition?
2. Has the 'Fire' relay latched on, (after a 'Fire' condition has been present) and not reset (auto-reset off)?
3. Is something partially blocking the beam to create a fire condition?
4. Has the threshold been set to 25% in a dirty environment (too sensitive)?
5. Has the transmitter/receiver head been moved slightly after alignment has been carried out?
6. Has the lens of the Tx/Rx become dirty (therefore reducing the signal but not exceeding the AGC limits)?