Douglas Krantz - Technical Writer - Describing How It Works
When first arrving on site to fix a fire alarm system, before pressing buttons, call the monitoring company and read the panel

How do I Troubleshoot Analog Addressable Systems?

By Douglas Krantz | Maintenance | 4 minutes of reading

Greetings Douglas,

Thanks for all your extensive explanation regarding fire alarms systems. My question is about the best way to troubleshoot an "analogue addressable fire alarm loop?" Is there a systematic approach in fault finding when loops are faulty?

Thank you, KR

The systematic approach to troubleshooting an Analogue Addressable Fire Alarm Loop is exactly the same as troubleshooting any problem with any fire alarm system. Remember, all fire alarm systems have devices in the building, all fire alarm systems that have a display have a control panel, all fire alarm systems use wires to connect everything together, and a few fire alarm systems also use Radio Frequency Signals (RF) or fiber optics for communication.

Most of the time, when troubleshooting a fire alarm system, what you have to remember is that the system is made up of boxes (panels and devices) and they're connected by wires. However, whether the fire alarm system is analogue, digital, addressable, or conventional, troubleshooting the fire alarm system uses the same technique.

Troubleshooting is a process of guess and confirm, guess what you think is wrong and then confirm the guess. If you are correct, fix it. Until you have the experience to guess specifically what is wrong, start with the easy guesses to confirm, most problems are going to be an easy fix, so don't think complicated until you've exhausted all the easy confirmations.

Troubleshooting Process

To simplify the understanding of a fire alarm system, and to organize your thoughts for troubleshooting, there is a procedure that you have to use when first walking into the building.


Don't touch any buttons.

Call the monitoring company so, should something happen while you're there, they don't send the fire department.


Read the panel, look at the lights:
  • Is there a green power/normal light on the panel?
  • Is there a red light showing an alarm somewhere?
  • Is there a yellow light showing a supervisory alarm somewhere?
  • Is there a yellow light showing a trouble somewhere?
  • Is there a ground fault light showing that there is a ground fault somewhere?

This gives you a good start of what to look for.

Most fire alarm panels have a display showing what is going on. What does the panel say?

Is there only one message? Are there several messages? Are there dozens to hundreds of messages?

Once you've seen what the panel has to say, think simple. Do a quick walk-through of the area of the building that the panel is talking about. Look to see if there's anything obvious.

If you don't see anything obviously wrong, go back and read the panel again. Reading the panel again doesn't hurt, and reading the panel again refreshes the mind.

Still Don't Touch the Reset Button

Get out your voltmeter.

Open the panel and read the voltages on the screw terminals of the panel. Some of them should not be steady, some of them should be steady, get familiar with reading the voltages.

After doing all this, you have somewhat of an idea of where to start looking.

The next step is to guess, but now you have a better idea of where you should be guessing.

There is no easy systematic approach to troubleshooting a fire alarm system, especially because the system isn't just the box-on-the-wall, it's the wiring and devices throughout the building.

Troubleshooting a fire alarm system, or anything else for that matter, is a guess and confirm process. As you gain experience with making guesses and confirming the guesses, you will be able to take short-cuts and guess closer to the problem.

Douglas Krantz
Life Safety
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