NFS 320 Troubleshooting Tips

False alarms are a nuisance and source of stress for those affected, but they are also becoming a liability and potential extra cost for building operators in lots of different markets. 

In Ottawa, for example, the elevated number of false alarms in recent years has led to the introduction of escalating fines for false alarms that can be attributed to a lack of fire alarm system maintenance.

In many cases, false alarms can be traced back to small issues that could’ve been caught early with basic troubleshooting.

This guide offers real-world NFS 320 troubleshooting tips. If you are looking for the easiest ways to prevent system downtime and resolve some of the most common panel issues, this guide is for you.

How to Reset the NFS-320 Panel

To reset the Notifier NFS-320 panel, all you have to do is use the panel’s built-in keypad and press the System Reset soft key. 

If the system fails to reset or the trouble condition returns, it is likely because of an unresolved issue, which could be an open circuit, faulty device, or programming error that you need to address before attempting another reset. Once you verify all circuits and make sure that no devices are in alarm, supervisory, or trouble status, you’re clear to attempt another reset.

Diagnosing Ground Faults and Ground Fault Loops

A ground fault occurs when an energized conductor makes unintended contact with ground, either through pinched wiring, damaged insulation, or corroded conduit. In the NFS-320, a ground fault typically triggers a general trouble alert without specifying the affected loop.

To isolate the ground fault loop, disable all SLC and NAC circuits individually and re-enable them one at a time while monitoring for the fault. Start from the panel and move outward. A process of elimination will often narrow it down to a specific circuit or device. 

What Does a “Fault” Message Mean?

When the NFS-320 displays a generic “fault” message, it’s signaling a system abnormality that doesn’t rise to the level of alarm or supervisory. These could include device communication loss, NAC issues, or loop errors. 

Using the VeriFire® Tools diagnostic software—or the onboard event history—you can retrieve a detailed description of the fault, including timestamp, device address, and fault type. Always cross-reference these events with recent maintenance logs or environmental changes to pinpoint the cause.

Replacing Devices on the Loop

If you’ve identified a failed device (such as a smoke detector or module), you’ll need to replace it with the same model or a fully compatible part. The NFS-320 supports auto-programming, but after installing the new device, it’s still best practice to run a walk test to verify detection and reporting. 

For legacy sites, sourcing replacements can be tricky—Fire Alarm Depot offers a deep inventory of Notifier fire alarm parts, including legacy models and hard-to-find components.

Wiring Best Practices That Prevent Future Issues

Improper or inconsistent wiring is a leading cause of persistent panel faults and hard-to-trace troubles. Always separate power-limited and non-power-limited wiring, maintain polarity across circuits, and use proper strain reliefs. 

At the panel, ensure all grounding points are secured and that the cabinet itself is bonded correctly. Use shielded twisted pair for SLCs where required.

Release Zones That Are Often Overlooked

The NFS-320 includes up to ten release zones. Many installations never use all of them, but the panel’s capabilities support advanced setups for suppression or phased evacuation systems.

You can configure cross-zone behavior, delays, and abort functions directly through the panel’s interface. There’s no need for extra control hardware in most setups, which makes programming more streamlined and reduces failure points.

The Right Components Make Troubleshooting Easier

A panel as capable as the NFS-320 still relies on the system around it. If device compatibility is off, wiring isn’t clean, or loop configuration doesn’t match the install, issues will follow.

That’s where Fire Alarm Depot helps fill the gap. Our inventory includes a wide selection of new and refurbished parts from manufacturers like Notifier, Simplex, EST, System Sensor, and more. Whether you need modules, amplifiers, pull stations, or replacement panels, the goal is the same: keep systems functional without delay.

Refurbished parts are fully tested and verified before shipping, and backed by a six-month warranty that reflects the kind of field use technicians deal with every day.