Douglas Krantz - Technical Writer - Describing How It Works
Get the book Make It Work - Conventional Fire Alarms
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

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

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

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 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

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

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

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

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

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

Does it harm the panel if the trouble occurs during a weekend and lasts 2 or 3 days? -- I have a question for you about Troubles, Supervisories, and Alarms. Does it harm the panel if the trouble occurs during a weekend and lasts 2 or 3 days? What if the panel goes in alarm and lasts ...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 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

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

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

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

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

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

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

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

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

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

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 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

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

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

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

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 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 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

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

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

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

Can a Duct Detector That Dirty be Cleaned? -- Well, the contractor said the new air handling equipment wasn't even turned on until after the walls had been sanded and painted, but apparently... 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

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

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

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

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

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

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