Douglas Krantz - Technical Writer - Describing How It Works
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Are As-Built Drawings Available When Needed? -- When available, as-built drawings are used by architects and engineers for remodeling or for designing new additions to... Read More

Do You Have to Replace Fire Alarm Batteries in Pairs? -- The question is asked: In a fire alarm system, where backup batteries are wired in series, can the batteries be changed out one at a time, or do the batteries have to be changed out in pairs? Remember that the... Read More

Can Low Tech Follow-the-Wire Help Troubleshoot? -- Someone once said "Experience is something you gain when things go wrong." Well, wiring issues are things that have gone wrong, and a lot of experience... Read More

What is a Ground Fault? -- With the exception of the ground fault circuitry inside the fire alarm control panel (FACP) itself, the wiring for fire alarm systems has... Read More

Can a Magnet Really be Used to Test a Smoke Detector? -- Smoke detectors usually have two ways of being tested. Smoke (smoke particles in the air, or some sort of canned smoke), and magnets (the activation of an internal magnetic... Read More

Does Anyone Return to Make the Installation Look Good? -- My father-in-law once told me "Make it purdy the first time; you'll always come back to make it work, you'll never come back to... Read More

Why Do Ground Faults Keep Happening in Some Buildings? -- Someone on a condominium board wrote about recurring ground fault issues with his building. Some of the other board members... Read More

How Does One Remove Tarnish from Electronic Contacts? -- Has this ever this happen to you? The electronic circuit you're servicing isn't working. You take it apart, look at it, and... Read More

How Does One Find a Soft Ground Fault? -- Normally, we think of resistance like that of a resistor. The amount of resistance is built-in; no matter what voltage is used to drive the electrical... Read More

How do I Connect 24 Volt Horns and Strobes to a 12 Volt Panel? -- I have a Silent Knight 5104b panel with a few IDC's and about 8 Strobe Horn combos. Problem is the FACP is 12 Volt DC and the Horn/Strobes are 24 Volt DC. Without swapping out all the Strobes with 12 volt strobes and have to get a lift or swapping out the 5104b with a panel that is 24 VDC, Can I connect a 24 Volt Power Booster to the 5104b and ...Read More

Can You Help Me Connect Devices to a Loop? -- Can you please help me connect devices to a loop? Can you install detector and a pull station on the same loop as a sounder, or are they separate loops?...Read More

Why Can't I Reset the Panel After Disconnecting the SLC? -- I disconnected the SLC (Signalling Line Circuit) from the Loop Controller Module on the fire alarm panel. I tried to reset the fire alarm system, but it wouldn't reset. What does that mean? Is there a short on the loop? The loop is disconnected, is there a problem with the Loop Controller Module?...Read More

How do You Use the Switches for Addressing? -- The DIP (Dual In-line Package) Switches are a little simpler than the thumbwheels (and therefore more cumbersome). A switch has 2 positions (0 through 1) rather than 10 positions (0 through 9) or 16 positions (0 through F). They work in Binary; either they are off or they are on. Two-positions means Binary, and Binary is the type of signal sent over the two wires of the Signaling Line Circuit (SLC)...Read More

Can a Control Module & Pull Station be Sequential (M001-M002)? -- The M001, M002, M003, Mxxx, is the software definition of specific inputs or outputs from the fire alarm panel. M probably stands for Module. The numbers 001, 002, 003, etc. module number assigned on the addressing thumbwheel or dip-switch of the module, or programmed into the module using a programming tool, or by the panel... Read More

Can I connect an addressable smoke detector to a conventional fire alarm control panel? -- In order to "detect fire and warn people of fire", the type of smoke detector and the type of fire alarm control panel have to match. When looking at whether or not an addressable smoke detector can be used on a conventional fire alarm system, we have to look at both the detector, and the fire alarm control panel. We also have to look ...Read More

Area of Refuge, what should the upkeep and temporary usage be? -- What should be maintenance aspect of Refuge area in terms of Upkeep, Temporary Usage etc.? We often get request for temporary stowing and using Refuge area for minor works including welding. Read More

Standby Batteries - Is there a reason why I shouldn't change them myself? -- I am OK with the cost per battery but I am having a little heartburn over paying someone $115 to do a simple replacement of the batteries. UNLESS I am missing a step that I am unaware of? I believe I need to notify our alarm company that I am changing batteries and to put us in test mode. Read More

Can a Backup Generator be Used for a Fire System? -- For backup, does the signal power expander only use batteries as the power source or would a/c or a generator ever be used? Read More

How Can I Tell if the Batteries are Bad? -- When I first checked the batteries they read 12.65 Volts and 22 Amp Hours. I checked the batteries with a battery tester, not a multi-meter. After the low amp hour reading, it was recommended they replace the batteries due to low amp-hours. According to NAPA 72...Read More

How Can We Fix Intermittent Beeping Troubles? -- We have a fire alarm system installed ~ 2000, it started beeping trouble, runs through all the points as troubles, then restores to normal. Fire alarm technicians cannot figure it out. Read More

Can You Tell Me how the Red Box on the Wall Operates? -- I moved into a 1-bedroom apartment recently that has 3 smoke detectors (the flat, round kind mounted on the ceiling), but also mounted on one wall is a red strobe alarm... Read More

Can the Alarm Relay Contacts Be Used For Elevevator Capture? -- Usually those contacts activate with any alarm. To keep the elevator from being captured when a smoke detector in any part of the building goes... Read More

Can Class A wiring be used for speaker circuits? -- Our client is insisting on Class A for the speaker circuits, instead of Class B... Read More

Is it OK to Disconnect the Ground Fault Circuitry? -- I was researching a ground fault issue my client is having with his plant fire alarm system and a VFD installed in the plant. Would you happen to have any experience with this sort of failure or could you recommend ... Read More

Can Ion and Photo Smokes be Used Together? -- If these smoke detectors are stand-alone smoke alarms, that is they have sounders in them, and if these are going to talk to each other so if one goes into alarm, all of ... Read More

Can We Use Waterflow Switches for Liquid Suppression Systems? -- Can we use the Flow Switches and Pressure Switches that are used with water lines, for fire suppression system, if fire suppression system uses NOVEC 1230 liquid? Read More

Can More Than One Class A Circuit be in a Conduit? -- How many Class A Circuits are in a single conduit isn't really the issue. The issue is separating the feed part of any Class A Circuit from... Read More

Which Proposal - Module in Stairwell or in Panel? -- Question: We're planning to have addressable panels installed and we've seen two approaches proposed by vendors for connecting the switches. One proposal uses addressable input modules at each switch, while another uses addressable zone modules in the panels. Is one method better than the other? Since the switches are already in zones by floor per building, they can be pinpointed already... Read More

Can an SLC loop (Signaling Line Circuit), whether Class B or A, also carry the power to activate (turn on) a horn strobe? -- The Signaling Line Circuit (SLC) is meant to carry signals between addressable devices (Modules and Detectors) and the panel. In some ways, the addressable devices can be thought of as extensions of the panel itself. The SLC can be thought of... Read More

How do You Find a Ground Fault? -- When there's a ground fault, the fault is an electrical leakage. It could be a hard ground fault, like a copper wire in the fire alarm system contacting ground. It could be a soft ground fault leaking electrical current through worn or pinched insulation, or even a soft ground fault caused by water on the wiring or devices. It could be an induced ground fault like the magnetic coupling of power inside of conduits. An ohmmeter can easily detect a hard ground fault. It's not so good with...Read More

Can the Booster Power Supply be Installed in the Ceiling? -- The fire alarm system isn't going to be removed after the warranty period; the fire alarm system is going to be in place as long as the building stands. Not only that... Read More

Can Two Different NAC Circuits be in the Same Conduit in Class A? -- Keep in mind that the purpose of Class A isn't so any problem with the wiring can be repaired in a timely manner; the purpose of Class A is to keep the system working once ... Read More

Is it allowed by code and the AHJ (Authority Having Jurisdiction) to use wire nuts? -- The AHJ is the government's representative - the fire marshal or fire inspector, the insurance company's representative - the insurance inspector, the building owner - the architect and engineers with the overall design of the fire alarm system, and so on. I'm paraphrasing, but in essence, the NFPA Code, in their definitions, defines the Authority Having Jurisdiction as each of these...Read More

How does Capacitance and Shielding Affect Wiring? -- Especially with shielded wire, could you explain the role capacitance plays in fire alarm circuits? I have a very basic understanding of how a capacitor works -a storing of voltage- but I've heard stories of capacitance causing issues on SLC circuits. Could you elaborate on that? ...Read More

Help - I have a City Circuit Trouble on My Panel -- I have a question about our Simplex 4005 fire panel. It is showing a "City Circuit Trouble 1". It's after hours and on the weekend ... Read More

Should We use Canned Air with Smoke Detectors? -- I have called the fire alarm manufacturer and their response was - Warranty void if you blow canned air into the smoke detectors. Yes.. it's what we have been taught to do. But if the manufacturer won't back this practice, why are we doing it? It's a concern. I am field guy. If the device can't take a bit of a beating then it needs to be replaced. If I am to train my team in general practice, then I have to be sure. To blow canned air, or not. That is our question...Read More

Is Compatibility an Issue with Smoke Detectors? -- We added the devices and there was not any indication of fault in the system. So I assumed that it was OK. But when we alarm tested the new detectors ... Read More

What does Open Zone Alert Mean? -- An Open Zone Alert on a fire alarm panel shows that the wire is not continuous. The fire alarm system, being a life safety system, is always checking the wires to make sure the devices like smoke detectors or pull stations are connected at all times...Read More

How do I Fix a Damaged Loop? -- When troubleshooting, the exact number of troubles aren't the important part - the fact there are any troubles is the important part. Keep in mind there may be many real troubles that have to be fixed one at a time, or there may be only one trouble causing the panel to detect many -troubles-...Read More

What Does DC TOO LOW 2 Mean? -- That's a question that is better asked of the technical support people at GENT. They can help you with all the messages on the screen, and with many other troubles with that exact panel. Before talking to them, though, make sure you have...Read More

Are Dead Fire Alarm Batteries Dangerous? -- The batteries are needed in case there is a power blackout. As long as there is no blackout, the batteries aren't needed. But then, blackouts are difficult to predict, so batteries are needed, just in case. The Amp Hour rating printed on the side of the battery is the size of the container. The 7 Amp Hour batteries, when they are fully charged, are capable of providing 1 amp of electrical current for 7 hours. If your fire alarm system is...Read More

Should I Replace the Smoke Detector if it is 80% Dirty? -- Inside the detector is a computer that senses how much light is reflected over a 24 hour period, and averages that amount. It then adjusts the smoke detector to be less sensitive, so only dangerous smoke suddenly entering the chamber will be considered dangerous smoke...Read More

Can I Make an Earth Fault Disappear? -- If dip switch is disabled in the fire alarm control panel, can it make a fault disappear, such as an earth fault? - - An Earth Fault or Ground Fault light is a warning light on the fire alarm system saying -Somewhere in the building, electricity is leaking to the earth or ground-. The Earth Fault usually isn't in the box-on-the-wall called the fire alarm panel - the Earth Fault is usually...Read More

How Can I Feel More Secure when Working on Fire Alarms? -- The first thing you do when you arrive on site is to inform those in charge that you are there and that there is a real possibility that the alarms will sound off. Never sugar-coat the explanation, it always is a possibility. Let management know that sounding off the alarms can't always be helped, but you are going to try to prevent that from happening...Read More

Will a Trouble on a Device Sound the Alarm? -- Do you mean by Alarm Signal, a Fire Alarm that gets everybody out of the building, shuts doors, shuts down the air handlers, stops industrial processes, etc.? The answer to what happens when an input or output device goes into trouble is a little less clear...Read More

Is it possible the door holder relay is breaking down? -- A door holder circuit system has four major parts: - The Power Supply with its Breaker and the Main Distribution Board Breaker - The Wiring in the Building along with other equipment in the building attached to the power supply - The Door Holder Electromagnet - The Door Holder Relay ... Read More

Can a Button be Installed to Release a Door Holder? -- The workers have to pop the door off the magnet when church starts. Some of the workers are older and have difficulty closing the door. Read More

How do magnetic door locks work when a fire occurs? -- How do magnetic door locks work when a fire occurs & a signal goes from fire control panel through a relay contact? -- Magnetic Door Locks and Magnetic Door Holders work the same way. When power is applied to the door lock or door holder, the electromagnet is turned on and keeps the door locked or the door held open. Once a fire alarm occurs, the fire alarm panel sends...Read More

I'm Having Trouble With a Door Release -- While trying to trouble shoot why the door release for the front door is not working, one of the conductors grounded out against the fire alarm panel chases. This caused the door release to activate. Any thoughts? Read More

Who do I Call to Reset the Duct Detector in my RTU? -- The fire alarm people are experts on smoke detection, including duct detectors. These are the people who can help reset the duct detectors, or replace the duct detectors if they're faulty. First, though, you can at least try to reset the duct detectors yourself by shutting off the power to the RTUs for about 5 seconds and then turning the RTUs back on. If that fails to start up the RTUs, or if the RTUs stop after a short while, call the fire alarm installation company...Read More

How is an Addressable Elevator Capture Panel Connected to a Conventional Panel? -- I would like to know, how do I to install (wire) two panels (One Conventional) (One Addressable) - to work together? - The Conventional panel is in general alarm for the whole building, and the addressable is for the new elevator recall. The Conventional sends the alarm to a remote station... Read More

What is the End of Line Resistor For? -- To fully understand what it's for we need to look at the fire alarm system itself. The fire alarm system isn't located just at the control panel, the fire alarm system is all over the building; the control panel just controls rest of the system. The fire alarm system is a means of detecting a fire -smoke detector, pull station, waterflow switch, heat detector, etc.) and a means of warning people about the fire (fire horns and strobes announcing the fire to people inside a building as well as well as calling the fire department-. There's also a fire control system that sometimes suppresses the fire and limits the spread of smoke...Read More

Is There a Procedure to Install EST Detectors? -- I have an EST3 fire alarm system. Is there any procedure to install heat detectors and multi-sensor detectors? After fixing how many smoke detectors, can we install heat detectors or multi-sensor detectors? ---- Fire alarm systems are Detect and Warn systems. If the detectors on any type of fire alarm system are changed...Read More

How do you Troubleshoot an Addressable System? -- No matter what the panel says, or what a multimeter says, all faults are either an open or a short. Both causes could be in the building wide fire alarm system at once, and there may be more than one problem to contend with. Shorts could be inside a device, in the building wiring, or in the panel- opens could be inside a device, in the building wiring, or in the panel. A ground fault is a short, and ground faults require two shorts in order for a ground fault to affect the fire alarm system. At all times when troubleshooting, keep an open mind. Never assume that you know what the problem is until the problem is fixed...Read More

What is the Difference Between a Fire / Smoke Damper and a Fire Damper -- The first answer is that a FSD is a Fire/Smoke Damper that closes with either fire or smoke, and the Fire Damper closes only with fire and stays open with smoke. There are similarities and differences between them. Either one can be manually reset or automatically reset (opened). In essence, it's inside the damper that the detection takes place. A fire damper closes when heat from a fire is detected at the damper, smoke damper closes when smoke is detected inside the air duct at the damper, and a fire / smoke damper closes when either smoke or heat is detected... Read More

Can Fire Alarm Fiber be Run in the Same Conduit as BMS? -- Can fire fiber riser be run in the same riser conduit with BMS? We only have one riser conduit for both. The engineers are saying we need two separate conduits, your thoughts? Read More

Do We Have to Replace the Entire Panel? -- Panel works fine, all components, until there is a drop in electrical current or the panel loses power completely. There are two battery back-ups, 12v 7Ah each, but for some reason it doesn't seem to help. We also tested it by shutting the ...Read More

I Need to Replace and Old Fire Alarm Panel -- Looking for a upgrade from a old fire alarm panel to a more modern model. The building is 3 floors with 8 suites and has magnetic door latches that are released when there is a heat detector or pull station in use. The old fire panel was made in 1987. What make and model of fire alarm panel would be able to work with the existing conventional heat & smoke detectors ...Read More

How do I Connect an FM200 System to the Fire Alarm System? -- It looks like you have two totally separate fire alarm systems - the EST system and the FM200 system. Each one has its own detection system, horns and strobes, and actions that they take when they have an alarm.The EST system doesn't tell the FM200 system to do anything. When there's an alarm on the EST system, the FM200 system doesn't do anything or display...Read More

Should the Generator Stop when the Horns Stop? -- I have generator that shuts down when the fire horns stop. The old generator has no real diagnostics to see what the problem is. Is there a solution?...Read More

Do I Have to Go Off Line? -- Do I have to go offline to replace the batteries in the duct detector panel? Also, will I have to reset any equipment or systems? Read More

How Can I Find this Intermittent Ground Fault? -- A ground fault is an electrical leakage to building ground on a fire alarm system. The ground faults are most commonly in the wiring. Devices themselves, unless there's water damage, are usually electrically isolated so they won't be the cause of a ground fault. The ground fault shown on the panel can be caused by...Read More

Do Heat Detectors Have an Operational Life? -- A fixed heat detector is activated by melting a ring of low-temperature solder, which releases a spring-loaded button...Read More

How Can a Door Holder be Hot and Buzzing? -- You describe two problems. The door holders are hot and the door holders buzz. Two types of electrical power could be used for the door holders, AC and DC. Some of them are AC only, some of them are DC only, and some of them can be either AC or DC. Usually the rating is stamped on the door holder assembly somewhere. Read More

How is the Sensitivity of a Smoke Detector Determined? -- To determine how much smoke it takes to set a smoke detector into alarm, sensitivity testing uses a calibrated, portable cloud chamber. It uses a photo-reader, kind of like the smoke sensing chamber inside a photo smoke detector, to sense the amount of smoke in the cloud chamber. The cloud chamber, or testing tool, completely encloses the smoke detector and starts out with clean air. For the measurement, artificial calibrated smoke is slowly introduced into the chamber...Read More

How Do I Shut Down Auditorium Sound on Fire Alarm? -- I have an auditorium that needs to have the sound shut down when the fire alarm is activated. The sound board or DSP (Digital Signal Processing) has an emergency input that I can connect to, but the prints are engineered to use the SLC loop to shut it down ... Read More

How are NAC Circuits Activated by the Panel? -- Simply said, to sound the alarm, the fire alarm panel -in a Conventional System- turns on the fire horns and strobes on a Notification Appliance Circuit (NAC) by turning on the power -in the alarm voltage polarity-; to check the wires (Supervise the Wires) when the panel is not in alarm, the fire alarm panel is constantly..Read More

How Do I Connect Two Fire Alarm Panels Together? -- Whether it is one addressable and one conventional panel, or two panels of any sort, there is one issue that has to be dealt with before anything else is taken care of. The issue is that someone untrained and not you are not going to be there to reset the system when there is a false alarm. This is a given, and this is the problem that has to be addressed when using two panels to cover the same building...Read More

How do I Connect a Tamper Switch? -- When connecting sprinkler tamper switches or sprinkler waterflow switches, I have found that the best way to make sure the system is going to work correctly is to not use the labels on the switch inside the tamer switch assembly. Half of the time those labels are wrong. Those labels are for any system, sort of, and not just for fire alarm systems. Instead, use the Ohmmeter to figure out which screw terminals to use...Read More

How do I Network Six Panels Together? -- I have 6 conventional Zeta Fire Panels. I want to make all network together for monitoring from one panel...Read More

How Do You Troubleshoot a Shorted NAC? -- First off, we have to understand what a NAC (Notification Appliance Circuit) is: it's the wiring outside the fire alarm panel that goes to the horns and strobes, (the notification appliances - the devices). The circuit is a pair of wires that connects all the devices in a chain fashion, like a single strand of beads on a necklace. ... Read More

How do I troubleshoot a ground fault? -- Troubleshooting a ground fault is like troubleshooting anything else. The first thing to do is stop and think. Ask yourself, what are you looking at?Read More

How do I troubleshoot a ground fault? -- Troubleshooting a ground fault is like troubleshooting anything else. The first thing to do is stop and think. Ask yourself, what are you looking at? Read More

Do Amp Hours Start on Backup Batteries When the Alarms Go Off? -- The backup batteries are 8 amp hours (8 AH), but do those amp hours start when the alarms go off or do the 8 AH start as soon as I connect them to the panel? ... Read More

I have Mechanical Room PIV Error -- An addressable panel, like the Siemens panel you're working on, uses a Signaling Line Circuit (SLC) for communication. This is really a computer data and power buss. This circuit ... Read More

I have this subject panel made by a company As Built -- I have a fault on the panel saying battery charger. I am unable to find the part for this panel. Can you help? ... Read More

I'm Looking for a Fire Alarm System -- I am looking to purchase a complete fire protection system for a Power Plant. I have searched and found some of the big names in fire alarm such as XXX Manufacturing, YYY Manufacturing, ZZZ Manufacturing, Etc... Read More

How Do I Get Rid of that Noise in the Speakers? -- What you are listening to is crosstalk. The sound is cross-talking from the Signaling Line Circuit (SLC) to the speaker wires. This crosstalk is a problem that occurs...Read More

You are right about keeping power and control wires separated -- Had a fire alarm system many years ago that had 24 volt smoke detector wires and 208 volt fan shut down wires in the same conduit: 250' run in the dirt under the bottom slab of a building. Read More

Is There Any Reference to Font Size for Labels? -- Is there any clear info on the marking as to Font size? As for 10.6.5.2.3 is there a better description for a red marking, one that is uniform with code?Read More

Can I Reset a Smoke Detector using Magnets? -- For test purposes, the first detector sets the panel into alarm, but the next detector tested will not set the panel into alarm because the panel is still in alarm. If you are testing just the smoke detectors and want to know whether they...Read More

Why Would a Smoke Detector be Wired Incorrectly? -- Do you know why a detector would not be wired correctly? Just wondered how that could happen as an electrician claims to have replaced 2 detectors because they were not wired correctly (even though he says he then correctly wired them), but why replace them then? I'm confused...Read More

Can Phone Lines, Fire Alarm Cables, and 120-240 Cables be Put Together? -- Besides the legal aspects, fire and safety issues, there's the interference problem. The voltages and currents from the 120-240 volt cables will be cross-talking to the low voltage cables. How much cross talk is produced will be affected by the actual currents in the high voltage cable, how tight they... Read More

How do I Find this NAC Trouble? -- The panel is looking at voltage on the NAC circuits - you need the meter to see the voltage that the panel is seeing. When there's no fire alarm on the NAC circuit, there are three voltages possible: Normal, Shorted, Open. These are relative voltages and the only way of telling if the voltage is correct is to compare the NAC 2 voltage to the NAC 1 voltage...Read More

Is There a Code Saying the NAC Can't be in Conduit with the SLC? -- The contractor wants to run the NAC and SLC circuit in the same conduit distance is about 13 feet. Is this allowable? Or must the two circuits be in different conduits? I looked in NFPA 2016 Chapter 12 and found nothing prohibiting running them together. However, my colleague said it is not permissible but he didn't tell me what reference in the code dictates this. What am I missing?...Read More

Why Won't the Horns and Strobes Work? -- When running the continuity check, the panel has to send voltage out on the wires. However, the horns and strobes can't be sounding off. To solve this, the panel reverses the polarity on the circuit to make sure the horns and strobes can't sound off when they aren't supposed to...Read More

Why reverse polarity for fire alarm horns? -- A fire horn is turned like a light; it turns on when power is applied and turns off when power is removed. But then again, to constantly check continuity of the wires (supervise the wires), the Fire Alarm Control Panel (FACP) always has power applied to the circuit. Read More

Why reverse polarity for fire alarm horns? -- A fire horn is turned like a light; it turns on when power is applied and turns off when power is removed. But then again, to constantly check continuity of the wires (supervise the wires), the Fire Alarm Control Panel (FACP) always has power applied to the circuit. Read More

Is it Permissible to Connect Addressable Devices in a Class A System? -- Notification Appliance Circuits (NAC) whether they're Class A or Class B have to be consistent. All of the horns, strobes, and any speakers on the circuit have to be of the same manufacturer, and work with each other in the circuit; they have to be compatible with each other. If they are of different types, some of the horns or strobes won't sound off at the proper rate, and possibly won't work at all. Some of the speakers will be either too loud or too quiet. When addressable horns, strobes, and speakers are on the same circuit as...Read More

Why Won't the Panel Show the Detectors? -- The panel indicates that it's OK, but the detectors are not seen on the panel... Remember, you are not just troubleshooting the panel; you are troubleshooting a whole building wide fire alarm system. Also, keep in mind, unless the installers of the fire alarm system are all very experienced, very few fire alarm systems are ever wired totally correctly the first time. Don't worry about the mistakes, everyone makes mistakes, your job is to...Read More

Where Can We Get Parts for our Unsupported System? -- Our fire alarm systems are no longer supported by the manufacturers, can you suggest how we can get the parts we may need in the future?... Read More

Where Can We Get Parts for our Unsupported System? -- Our fire alarm systems are no longer supported by the manufacturers, can you suggest how we can get the parts we may need in the future?... Read More

Where Can We Get Parts for our Unsupported System? -- Our fire alarm systems are no longer supported by the manufacturers, can you suggest how we can get the parts we may need in the future?... Read More

Can You Help Find a Manual for an Old Fire Alarm Panel? -- You might be able to find someone with a manual so you can fix the panel. This is assuming, of course, that the panel is bad and not something wrong elsewhere in the building. But fixing the panel means finding parts, which aren't...Read More

How do I Fix an Open Fault? -- The fire alarm system is supposed to consist of the wiring in the building, all of the input devices -smoke detectors, pull stations, waterflow switches, etc.- and all of the output devices -fire horns and strobes, etc.- Between all of the input zones and output zones is a control panel. There should be an end-of-line resistor at the end of each loop -the pair of wires connected to a zone and connected to all of the devices on the zone-...Read More

What Causes an Open NAC? -- I am going to a job site where on the service call ticket states that a NAC is reading open circuit. What can cause an open circuit on the NAC line? Read More

What Causes an Open NAC? -- I am going to a job site where on the service call ticket states that a NAC is reading open circuit. What can cause an open circuit on the NAC line? Read More

Phone Line Troubles Keep Waking Me Up! -- Every month between the last day of the current month and the 5th of the next month I receive phone line failures on my fire panel. It's clockwork. The troubles resolve shortly after the 5th of each month. The phone service goes "in and out" and the phone company can never find the problem and the fire panel technician can never find a problem. Of course, I am the one losing the sleep...Read More

Are All Smoke Detectors Polarity Sensitive? -- I have a question... Is it important for smoke detectors to be polarity correct? Are all smoke detectors polarity sensitive? Read More

Are All Smoke Detectors Polarity Sensitive? -- I have a question... Is it important for smoke detectors to be polarity correct? Are all smoke detectors polarity sensitive? Read More

What is the Difference in Power Supplies? -- What is the difference between an auxiliary power 24-volt connection from the control panel and other additional power 24-volt power supplies like the booster power supply? -- It doesn't matter whether the power supply is in the fire alarm control panel, or in a different box somewhere else, no power supply produces power; all power supplies only convert power. They require utility power (120 or 230 volts AC) and convert this utility power to the 12 volts or 24 volts DC that the fire alarm system uses. This includes the Auxiliary Power Supplies and the Booster Power Supplies (BPS)...Read More

Am I Allowed to Power Up on the Battery? -- Powering up a panel using only battery backup is a manufacture's design issue. Some manufacturers have fail-safe features that prevent a panel from turning on until utility power is applied; some manufacturers don't bother with the fail-safe features and allow the panel to be powered up using the batteries...Read More

Can I Relocate a Strobe Without Reprogramming? -- Do the technicians have to reprogram the fire alarm system after relocating devices just a few inches from their original position?Read More

Can I Relocate a Strobe Without Reprogramming? -- Do the technicians have to reprogram the fire alarm system after relocating devices just a few inches from their original position? Read More

Should a Battery Backup be 5 or 15 Minutes? -- There are two things to consider when deciding whether it's 5 minutes of evacuation, or 15 minutes of evacuation. One consideration is what building is going to be used for (its occupancy), and the other is what kind of fire alarm system is going to be needed for the occupancy ... Read More

Why Won't the Strobes Work? -- When there's an alarm, all the horns sound off, but none of the strobes flash. Can you help me or give me suggestions on how to fix this? I've never run into this problem before. I would like to have at least some ideas of what to look for. G D. There are several possible causes for the problems, Compatibility Issues, Signal Power Expander or Booster Power Supply, Polarity Issues, Voltage Drop Issues. Compatibility. The requirement that all strobes in an area flash at the same time requires that the manufacturers all come up with a method of synchronizing the strobes. This synchronization is to prevent...Read More

Is This an Addressable 4 Wire Speaker/Strobe? -- A speaker and a strobe are always separate devices. Many times, as with the speaker/strobe that you show, the speaker and the strobe my be in the same box, but they are still separate devices, they aren't connected together inside. In this case, this is not an addressable device. On the back of the speaker / strobe, there are 4 terminals: 2 of the terminals are for the speaker and two of the terminals are for the strobe. In other words, the terminals aren't for a single 4 wire addressable circuit, but the terminals are for two completely separate 2 wire circuits: 2 of the wires are for powering the strobe and 2 of the wires are for powering the speaker...Read More

Can the fire department make the owner bring the whole fire alarm system up to code? -- We failed the inspection with city due to lack of signage at pull stations in an existing apartment building. The signs are supposed to say LOCAL ALARM ONLY - IN CASE OF FIRE CALL 911 Read More

Can the fire department make the owner bring the whole fire alarm system up to code? -- We failed the inspection with city due to lack of signage at pull stations in an existing apartment building. The signs are supposed to say LOCAL ALARM ONLY - IN CASE OF FIRE CALL 911 Read More

When Testing, Why Isn't the LED Lit Continuously? -- First off, that blink you are seeing on the smoke detector is the time that the fire panel is communicating with that particular detector. Normally, every 5 seconds or so the panel is checking with each detector and module in the system to make sure all are connected, and to receive any alarms or troubles in the system. This check of the detector every 5 seconds is called...Read More

Why Don't All of the Smoke Detectors Act the Same? -- When testing, not all of the SDs are behaving in the same way, some of the SDs are only generating the alarm in the panel without latching the LED light. I've checked for ground faults. There was a panel negative earth leakage, but it has been fixed. The Signaling Line Circuit (SLC) power supply polarity of all the SDs re-checked. The panel was re-started. Unfortunately, some of the smoke detectors are still not latching in alarm....Read More

How Can I Clear the Trouble Tone? -- I have a trouble message. How can I clear the trouble tone? - - The trouble light and trouble tone are on the fire alarm system as a warning: Something's Not Working. As long as something's not working on the fire alarm system, the trouble light is going to stay on...Read More

What Wiring Method Should I use for Speakers? -- Whether it's going to wind up being a Class A or Class B wiring method for the speakers, whether it's going to be a conventional speaker circuit or addressable speakers, the method of a installing voice evacuation speaker system is first determined by the absolute minimum standards shown in the NFPA. Greater requirements can be indicated by any of the AHJs...Read More

When are voice evac systems required? -- In many cases, a fire alarm system is no longer just a fire alarm system. Voice Evacuation is allowing Mass Notification to be used over part of the fire alarm system to announce to the occupants what to do for other emergencies. In other words, an FAS (Fire Alarm System) doesn't just function as an FDAS (Fire Detection and Alarm System) but as a Fire Detection and Emergency Announcement System...Read More

When are voice evac systems required? -- In many cases, a fire alarm system is no longer just a fire alarm system. Voice Evacuation is allowing Mass Notification to be used over part of the fire alarm system to announce to the occupants what to do for other emergencies. In other words, an FAS (Fire Alarm System) doesn't just function as an FDAS (Fire Detection and Alarm System) but as a Fire Detection and Emergency Announcement System...Read More

What Voltage Should Be at the EOL of a NAC? -- The goal, when measuring the voltage on the Notification Appliance Circuit -NAC-, is to make sure that there is enough voltage to turn on all the horns and strobes when there is a fire. The power may be off to the building during a power blackout, but the voltage still has to be there for the horns and strobes to warn people of fire...Read More

What are the Signals on the SLC? -- I would like to know what type of signal is there between addressable fire detectors and the fire alarm monitoring panel. Actually I want to know how the address / location of... Read More

What Causes a Fire Alarm System Trouble? -- The word Trouble on a fire alarm system means -In the Fire Alarm System, including all the Input and Output Devices, Signal and Power Wiring, and Panels, something is not working correctly-. This is based on the absolute need for the fire alarm system to Detect Fire and Warn People of Danger. A trouble can be caused by...Read More

What Does a Building Cross-Section Look Like? -- From the description of what the engineers want, a Building Cross-Section looks like a standard Fire Alarm Riser Diagram - with ... Read More

What is a Fire Alarm Signal? -- I am a newcomer to the field of fire alarms. I would like to know what is a signal in fire alarm systems. Signed S M. To make sure they cover all possibilities, the NFPA uses legal type language to say anything. This is because the NFPA publishes what will become legal documents. Sometimes they use catch-all words that have many meanings... Read More

What is Causing a Network Fault? -- A Network Fault is a problem (Trouble) with the fire alarm system. The fault has to be fixed before it can be cleared from the panel. To clear the trouble from the display, there's also a trouble memory that requires the troubles to be acknowledged and cleared after fixing the trouble...Read More

What are the basic parts generally available in any panel? -- I mean any brand. Let's say Simplex, Siemens, Edwards, Notifier, whatever it may be. There must be some default parts in all the panels. Can you please tell me what are and what the functions are? Read More

What Voltage Should I Measure on the NAC? -- I have been trying to find a voltage spec for the voltage reversal signal that typically comes out of a fire panel. I have seen somewhere that is normally +24v and -24v when reversed. Elsewhere, I see that its +24v when in alarm and "some negative voltage" when ....Read More

Where Should An End-Of-Line Resistor go In A Security System? -- Shouldn't the EOL resistor be physically, actually, for-real be located at the END of the loop, at the farthest point? Otherwise, isn't having the EOL resistor right there at the panel just ... Read More

Who is Supposed to Remove an Old Fire Alarm System? -- Rather than relying on anyone else to remove an old fire alarm system so a new fire alarm system could be installed, the company I worked for always removed the no-longer-used-fire alarm system. As far as the National Fire Protection Association (NFPA) goes, however, even having a fire alarm system in the first place is the owner's responsibility. The owner only uses a fire alarm company for installation, testing, servicing, and replacement of the fire alarm system. As well as removing any old panels, devices, and wiring...Read More

Why Aren't There a Lot Of Troubles When Removing Wires? -- I have a question about a fire alarm circuit and I hope you will help me out. When I remove one positive wire from a smoke detector, I don't see it and any other loop devices missing in my trouble log, except the device I took off and a Style 6 Loop trouble. My question is, shouldn't I get a list of all devices which are connected in loop? For example, if I remove one positive wire from the Loop 3 smoke detector Number 34, I am receiving a "No Response Smoke Detector 34" and "Style 6 Loop3 Trouble" Why am I not getting a list of all of the devices that are in trouble? ... Read More

When I install an alarm bell, the Fire Alarm Control Panel (FACP) always shows "Alarm Short Circuit" on the FACP. -- I've already checked the wiring with my ohmmeter, it's OK. I've also changed the bell (buying a new one) but the panel still shows a fault. How can I solve this problem? Read More

Help! I Have Some Weird NAC Troubles -- A booster panel feeding unit strobes in a condo building will go into trouble only at night. The troubles occur between the hours of about 1am to 6am and then never have an issue at any other time of day. The booster clicks in and out of trouble very quickly while this is happening...Read More

How do I Wire a Replaced Tamper Switch? -- There are two ways to wire a tamper switch. Th old fashioned -trouble- method, and the new Code acceptable -supervisory- method. The first thing to do is figure out how this one is wired...Read More

Why Won't the Added Horns and Strobes Work? -- We attempted to add two horns and 2 strobes to the NAC circuit by extending the circuit and relocating the EOL resistor to that new end of line. When we did this, we get a trouble light. The cause of the trouble that has been isolated by troubleshooting to the NAC circuit. The new added strobes had a different power level than the ones already there, so we ordered identical ones. Still having the trouble light lit on the panel. Any suggestions? Read More

Can a Person Just Add a Horn or Strobe to an Existing Notification Appliance Circuit (NAC)? -- In a building that has been remodeled and remodeled, when a fire drill is sounded, have you ever found that a few strobes are running slow or won't even work? Then, when troubleshooting... Read More

Why Doesn't a Smoke Detector Always Detect? -- The NFPA wants smoke detectors tested in place to make sure smoke enters the smoke chamber. Keep in mind that a smoke detector can't detect smoke that ... Read More

What is an As-Built Plan? -- The owner of the building project is the beginning of the planning process and the end of the planning process. Conception Plans - How the building ... Read More

Why are Battery Date Codes so Cryptic? -- For safety reasons, the NFPA Code requires the replacement of fire alarm batteries within 5 years of manufacture...Read More

When Should Fire Alarm Batteries Be Replaced? -- The 2007 NFPA72 shows in Table 10.4.4, Item 6(d)(1), that the sealed lead-acid batteries used for battery backup in fire... Read More

When Should Fire Alarm Batteries Be Replaced? -- The 2007 NFPA72 shows in Table 10.4.4, Item 6(d)(1), that the sealed lead-acid batteries used for battery backup in fire... Read More

Why Use a Cheap Meter when and Expensive Meter is Better? -- Like a doctor always carrying a stethoscope, so should a technician always carry a... Read More

How do Pathways Affect Ground Faults? -- Ground Faults are a big issue. Almost anytime there is a ground fault on a fire alarm system, the panel displays a trouble. Then, no matter what caused the trouble, the trouble has to be fixed. However, the NFPA has an exception to the rules regarding the displaying of ground fault troubles. For all types of pathways for signal or power in building wide fire alarm systems, the rule of thumb for displaying a ground fault trouble goes something like this, -Whenever there is a ground fault, the panel will display a trouble.- There is an exception to this rule ...Read More

It's the Volunteer Firefighter that Reads the Panel -- I suppose it was used because the technician programming the fire alarm system was totally familiar with the acronym AFA and what it means... Read More

What Happens When a Fire Alarm System is Tested? -- Once in a while, I can completely inspect a fire alarm system - The system is local only, there is no monitoring company to disable - There are no people around to get confused or greatly annoyed as I sound the alarms... Read More

What Makes Interfacing the Fire Alarm to Elevator Capture Difficult? -- People are afraid of fire. They also know that where there's smoke, sometimes there's fire. That's why they don't want the elevator to... Read More

What is the Difference Between an End of Line Resistor and a Terminating Resistor? -- In electronics, at the end of the communication line, there's often a Terminating Resistor. In fire alarm and security systems ... Read More

Why Use Pigtails or a UL Approved End-of-Line Resistor? -- Many times, a fire alarm system installer will put the leads of an end-of-line resistor... Read More

How Does One Gain Experience? -- If every time one goes on site to fix the fire alarm system the problem is obvious, being a troubleshooter... Read More

What is a Friday Afternoon Repair? -- If the fire panel shows normal, you may never get back to fix a trouble; if the fire panel shows trouble, you'll always come back to...Read More

Can the Ground Fault Light be Used for Troubleshooting?-- A ground fault is an electrical leakage from the fire alarm system to building ground -- somewhere in the building. The ground fault light on... Read More

Horns and Strobes for Handicap Apartments -- Multifamily dwellings like apartments, condominiums, hotel rooms, etc., actually have two fire alarm systems: each individual residence's fire alarm system and the building's common fire alarm system. A fire alarm system, any fire alarm system, detects ... Read More

When a New Air Diffuser is Installed, Why is the Fire Alarm Company at Fault? -- I was at a lunch meeting where the State Fire Marshal (AHJ) was speaking. One of the things that he talked about... Read More

If It Aint't on Paper - Did It Happen?-- Paperwork - when things go right, no one reads it - when things go wrong, is that when they read it? Read More

Why Do We Inspect Fire Alarm Systems? -- A long time ago, before regular testing of fire alarm systems was required, the NFPA and other fire protection professionals discovered that large numbers of fire alarm systems just weren't working... at all. Originally, when they were installed, these systems worked properly ... Read More

Who Really has Job Security?-- If you guard secrets to keep job security, you'll lose it. If you give away secrets to give away job security, you... Read More

It's just one more strobe, what's the problem? -- Sometimes, after a building has been established for years, the fire marshal or the building owners want to add another horn or strobe. Or maybe, with remodeling, more horns and strobes are just added to an existing Notification Appliance Circuit (NAC). Really, it is just one more strobe and the circuit works... Read More

Is the Sense of Time Important in Troubleshooting?-- Sometimes, when servicing fire alarm systems to find the troubles, one has to use all the common senses available to observe more than just... Read More

How Does One Keep Track of All Those Wires? -- Changing a circuit board, whether it's in a fire alarm panel, a security panel, a card access panel, or some other panel, can be a potential nightmare if a mistake is made and the wires are mixed up. Read More

Do I Have to Put The Fire Alarm System On Test? -- It's the owner's fire alarm panel. The owner has bought and paid for the fire alarm system. You may be called... Read More

Quadruple Use of the Initiating Device Circuit (IDC)-- In a fire alarm system, the Initiating Device Circuit (IDC) is an input circuit or detection circuit: it carries the alarms detected by devices like flow switches, pull stations, heat detectors, tamper switches, etc. A second use of the Initiating Device Circuit is to monitor itself, it supervises its own wires... Read More

How many T-Taps are Allowed on an SLC? -- The answer to the question of how many T-Taps is allowed --- is It Depends. It depends on the manufacturer and it depends on how easy the installer wants to make the system for the technician... Read More

Can Stopping to Look at the Panel and Think Save Time? -- Sometimes, even after a lightning storm, what seems like a whole gaggle of troubles, is really only a few small troubles... Read More

When Talking to Customers, Shouldn't Their Language Be Used? -- You have been trained in the operation of fire alarm systems, your customers have not... Read More

Talk to Management Before and After Servicing-- When a technician is doing something, anything, with the fire alarm system -- people are concerned; they don't like being surprised by seeing someone messing around with their life-safety fire alarm... Read More

Should Canned Smoke be Used to Test Smoke Detectors? -- There have been many discussions about the best way to test smoke detectors --- canned smoke or... Read More

Troubleshooting Addressable Ins and Outs -- A fire alarm system's main purpose is to detect fire and then tell people about the fire. A conventional fire alarm system does this detection-telling, and so does an addressable fire alarm system. Besides a better display on the addressable fire alarm system and the extension of the ... Read More

Does the NO Mean Normally Open of Normally Closed on a Tamper Switch? -- To figure out the normally open and normally closed contacts for switches on fire suppression systems, use ... Read More

Can a Real Fire Break Out While the Fire Alarm System is Being Tested? -- That's what the fire alarm system is there for in the first place, isn't it? To shout fire? Keep that in mind when disabling... Read More

Why is Snow White? -- Question: If the sun is yellow, why is snow white? Answer: Because the Sky is Blue. Um, the riddle seems to be nonsense, but really...Read More

Douglas Krantz -- Fire Alarm Engineering Technician, Electronic Designer, Electronic Technician, Writer

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