Frequently Asked Questions

Alarm Annunciators

  • In many addressable systems, the serial lamp drivers must be connected and communicating with the FACP in order for the Lamp Test function to operate. In some systems, the device programming must also be completed in order for the Lamp Test to work. Verify programming.
  • Lamp Test switch contact(s) not closing when pressed. Verify with meter. Check all the way from the switch contacts to the serial I/O connections.
  • In an addressable Fire Alarm system the FACP must be programmed. The alarm initiating devices must be assigned to activate specific outputs of the associated serial lamp drivers. Even though these lamp drivers are often mounted inside the Annunciator, they must be programmed by the installer. Verify that the correct system programming has been performed.
  • FACP not programmed correctly as per annunciator wiring diagram.
  • Cables between the door and the serial lamp drivers in the box are not plugged in correctly.

*Please check the LED assignments and cables locations with the wiring
plan provided with the unit.

  • Make sure the LED is functional and that the wiring from the LED to the lamp driver board is intact. (Use a spare LED in parallel with the nonworking LED to see if LED is defective.) Visit LED web site for diagrams.
  • Yes, visit Light Engineered Displays web site for diagrams.

Water Leak Detection Systems

Most users want to place the leak sensing cable as close as possible to a potential water leak hazard, often placing the cable directly under the HVAC systems. This exposes the leak sensing cable to an increased potential for false alarms. The HVAC downdraft often contains particles of moisture that have been condensed from the cool surfaces inside the HVAC unit. Also, these HVAC units often have humidifiers which can add to the problem. Finally, over time, the high velocity air can embed fine particles of dust and dirt into the sensing cable, degrading its performance. Worse, if the sensing cable is not tightly fastened to the subfloor, the internal conductors may break from the constant movement.

  • The primary reason for false alarms is that the cable has been installed too close to an HVAC downdraft
  • Cable has been installed under a pipe that is sweating (condensation) or is heavy and is pinching (shorting) the conductors
  • The cable has become contaminated from dust and dirt over time.
  • Another possibility is contamination from mineral salts absorbed from an unsealed concrete subfloor.
  • Cable is contaminated from a previous leak.

When a leak sensing cable becomes wet from a system water leak, often there will be mineral salts and other contaminates from the subfloor tat remain in the cable after the water has evaporated. The more times the cable has been wet and dry, the more likely it is there will be contamination. Sometimes the cable can be cleaned. Sometimes replacement is required.

Almost all “footage measuring” leak detection systems calculate the electrical resistance of the sensing conductors to determine the location where water has contacted the sensing cable. When a water leak contact the cable, an area of low resistance forms at the point of contact. On occasion, conditions will cause a small decrease in resistance over a large section of cable. Electrically, this is like a short circuit over a single spot. When the total decrease of resistance is enough to cause a false alarm, it will logically be indicated as being at the end of the cable because that is the normal point of highest resistance. This condition is usually caused by an HVAC unit blowing a fine mist of water particles from the condensate pan or humidifier.


*Technician’s Note: Refer to a system manuals for information about setting the calibration and sensitivity settings as well as general system design criteria.

Mass Notification Systems

  • Maximum distance will depend on using only the specified wire and the correct wiring techniques. For the MNS Series, use a 24 gauge, stranded, twisted pair with shield and drain, low capacitance, 120 ohms @ 1000 ft. With the default setting of 9600 baud, the maximum will distance will be 4000′ and 30 signs to a data line.
    NOTE: An optional RS-485 repeater is available to increase the above limitations.
  • NO. The data cable must be routed in a “daisy-chain” manner. Individual home runs, T-taps and parallel connections will cause problems that result from reflected signals canceling active signals – thus some signs fail to activate and/or fail to keep correct time.
  • Different models have different requirements. Some signs are powered locally at each sign with 115 VAC, 60 Hz. Use an EXIT sign branch for power as this is usually a protected circuit and often connected to the building emergency power system. If the sign uses a plug-in transformer, install an outlet near each sign location. The transformer must be plugged-in to the AC outlet and the transformer cable must be plugged in to the jack on the back of the sign. If AC terminal blocks are provided inside the sign, then hard-wire the AC power as per local codes.
  • Some models require 24vdc power. This may be provided from the FACP 24v power, or other auxiliary power supply featuring battery backup sufficient for sign system needs. Check the product literature for current consumption. Make sure to use wrirng of sufficient gauge to insure there is no loss of voltage all the way to the last sign connected.
  • Check the sign product literature for voltage requirements and current consumption.
  • Standard 8 message controller operates from 24vdc and can be connected to the auxilliary power on your Fire alarm panel or Voice Evac panel.
  • Powerup: 200 ma.
  • Standby: 82 ma.
  • Each Activated Alarm adds 6 ma.NOTE: When programming a system, do NOT enter “configuration mode” on the controller.