Whole home fire alarm system goes off at random intervals and I want to murder it

Hi there everyone!

We bought a home in April with a whole home fire alarm system. Prior to that, we lived in an apartment with a whole home fire alarm system. I've never lived in a house that had hard-wired alarms before, only ever had the battery-opperated ones and *never in my life* have had a problem with them going off unless I burned something cooking.

Over the last year between the apartment and the house, we have had our alarm systems in both places go off at random times seemingly for no reason at all. Yes, I realize that there is, of course, a reason: the voltage across the detector dips triggering the alarm. But that is generally caused either by dust or smoke. We've had it go off randomly at 2am. We've had it go off in the middle of the day and return home to a note from the fire department saying "Gee sorry, your alarm was going off for 3 hours so we broke in to your house and shut it off because of a noise complaint from neighbors." Yea. Nuts.

Every time we check EVERY ALARM in the house. No smoke. No smell of smoke. Nothing.

In the apartment, we were running a humidifier at night, and one electrician we consulted said "That would never cause a problem" while another said "Yea, that's definitely what is setting it off."

SO...we stopped running a humidifier (even though I ran one as a kid with a battery-powered fire alarm in my bedroom and never once had it go off EVER). Now we have dry, scratchy throats in the winter and guess what? Still goes off anyway.

Just had it go off maybe 30 minutes ago while I was sitting here working at my computer, another person in the house was working on a different computer, and a third person was in the bathroom doing their eyebrows.

Nobody was cooking anything. No gas going. No smell of smoke. Nobody dusting. Nothing happening in the house really. Just went off. SCREAMINGLY loud. Couldn't get it to stop for about 5 minutes ,then it just randomly stopped all on its own.

We always try pushing the buttons on the alarms that say "push to silence" (it never works). We also open all the doors and windows in case there is some invisible thing setting it off. Never seems to help, just goes off on its own.

We had it go off at 2am one time and then just shut off after about 15 seconds. We were like "Hey, cool, thanks, house!"

We have four pet rabbits who *FREAK OUT* when these alarms go off. I don't want my rabbits to croak and start pushin' up daisies. Please, for pity's sake, is there anyone out there who can offer some suggestions on what we might do to never have this happen again? I should note: We are required BY LAW to have fire alarms at the top and bottom of every stairway, in every bedroom, and on either side of entrances to the kitchen as well as by entrances to the home. We also have 2 in the basement. Tallied up, we have 14 fire alarms. So what I super duper do NOT want to do is "just go ahead and replace all of them".

If they are hard-wired to the home, I assume (maybe incorrectly?) they aren't running off of Americium, i.e. the electric current in the detector is coming from the electric grid, not from radioisotopic decay. So I assume they don't need replacing due to half-life issues. And at any rate, if it was a half-life issue, I would expect the things to keep going off constantly once radioactivity dropped below threshold current levels, yet that isn't what is happening. We have it go off 1-2 times a quarter, always at random times when nothing is happening.


Sorry, I know that's a long rant...it's just...one of those problems that isn't consistent, so I know it's super hard to diagnose what might be causing it, hence I'm giving as much detail as I can. Any thoughts? We've talked with electricians a couple of times and have a call in to the fire department in town.

Thank you so much!

Replace with battery powered alarms that will start chirping in the middle of the night...

Gray Henon wrote:Replace with battery powered alarms that will start chirping in the middle of the night...

What would this accomplish?

All I can suggest is get battery powered ones. They seem more reliable.

I had the hardwired system in a house and it sucked.  As far as I could tell, the hard wired part was to make them all go off at the same time.  They still ran off their own batteries.  So I was still chasing chirping smoke detectors in the middle of the night to swap batteries even though the damn things were wired together.  

But my problem was with low batteries causing chirping, maybe when yours are low they set off the damn things?  

Mike Haasl wrote:I had the hardwired system in a house and it sucked.  As far as I could tell, the hard wired part was to make them all go off at the same time.  They still ran off their own batteries.  So I was still chasing chirping smoke detectors in the middle of the night to swap batteries even though the damn things were wired together.  

But my problem was with low batteries causing chirping, maybe when yours are low they set off the damn things?  

Oh, yes sir this is not a chirp. This is full on 50 decibel ear-splitting klaxon bullcrap.

I will say, a few weeks ago we had a power outage in a storm, and after the power came back on, one of the detectors in the basement started chirping. I replaced the battery right away and none of the others had a problem.

I will try getting all new batteries for the whole house. Anybody have recommendations for the best ones to use?

More data please. Make and model?

I hated those things...

I had one faulty detector, it would trip them all off.  I disconnected all of them from the hardwire until I could figure out which one was at fault and then replaced it.

I have had battery powered ones go off randomly, turned out a bug flew/crawled into the sensor.

Douglas Alpenstock wrote:More data please. Make and model?

Make is First Alert. There's a mix of them on the house, some with voice and some with siren only. Don't know model numbers because they came with the house and I'm not about to monkey with them and set them off screaming again at 10 o'clock at night because my partners would murder me and float the body down the river. 🤣

R Scott wrote:I disconnected all of them from the hardwire until I could figure out which one was at fault and then replaced it.

+1. That is what I would do. I don't think we're looking at a commercial grade system.

Warning: farting may or may not set off that brand......

D.W. do you do any maintenance on the smoke detectors? batteries, yes? but do you clean the detectors? blow out with canned air duster?
Agree on process of elimination (replace all batteries with new, clean all detectors) and also isolating detectors if problem still exists.
Are detectors identified at a panel individually or in zones, maybe by floors? that you could narrow it down?

Another thing to consider is professional help.
As in, hire an alarm company to come assess the system. They may know if you have old equipment in need of updating just by looking at it, or how to troubleshoot it quickly.
At work, we had a 25 year old system, that could no longer be repaired due to an obsolete panel.
Another time it was a faulty high water sensor that the guy fixed in 5 minutes because he knew to check a resistor and had a spare.

Kenneth Elwell wrote:D.W. do you do any maintenance on the smoke detectors? batteries, yes? but do you clean the detectors? blow out with canned air duster?
Agree on process of elimination (replace all batteries with new, clean all detectors) and also isolating detectors if problem still exists.
Are detectors identified at a panel individually or in zones, maybe by floors? that you could narrow it down?

Another thing to consider is professional help.
As in, hire an alarm company to come assess the system. They may know if you have old equipment in need of updating just by looking at it, or how to troubleshoot it quickly.
At work, we had a 25 year old system, that could no longer be repaired due to an obsolete panel.
Another time it was a faulty high water sensor that the guy fixed in 5 minutes because he knew to check a resistor and had a spare.

Have no clue how to maintain them. Never have in my life and have never had any problems until now.

Fire chief in town have me some advice though that I'll share:

1. It's got nothing to do with batteries
2. It's got nothing to do with which alarm is "talking", all three voice ones will talk when they go off regardless of which unit triggered the alarm
3. The way to tell which one is causing the problem is to look Kat the lights on the units. Alarms that are not the culprit will have a green blinking light. The alarm that was tripped will have a different colored light, usually red or amber. That's the unit that needs service or placement.

So now I get to wait until the next time an alarm goes off and then sprint through the house trying to see which unit is showing a red light! Oi.

our hardwire alarms have batteries so they work during power outages.  these batteries need changing twice a year in theory.  in reality they need changing every 5 months or they go off.

lesson, hard wire alarms probably have battery backup.  otherwise, how would they work in a power failure?

This may not be correct, but you might want to see if there is a detector that is part of the system in the attic. There could be a bird's nest or something in it?

Also, if you're going to change all the batteries, you should also turn off the power to the smoke alarm at the circuit breaker to reset it properly. Remove the smoke alarm from the mounting bracket and disconnect the power when you remove the battery and hold the reset button for 20 seconds or so, then reconnect the power and put the battery back in. Hopefully the batteries will be the issue.

Had the same thing happen with the same brand.  They have problems with humidity and start failing after a time.  We live in the fog zone so they eventually start to fail.  Had to replace everyone on in my house,  so wasteful.

D.W.,  I think I know what is going on here.

I once had a similar issue.  I built my house new, and the basic code for new construction around here was to have a wired system, much like the one you have.  And not long after we moved in (maybe a year or so?) the whole house would shriek at us with the painfully loud blast that you described.  There was no smoke and there was no fire.  We were trying to go to bed and we had a small child.  We eventually called an electrician as we had no other idea what to do.  

Once the electrician arrived he simply walked around and inspected the different alarms and eventually removed one and the 20 minutes of ear-piercing screams quit.  He told us that the one smoke detector had gone bad and that they do occasionally need to be replaced.  We thanked him (he did not charge us, but he does get our business now) and he left.

But I did not learn the reason why smoke detectors do this until recently.

So the basic properties of a smoke detector is that it has to not only reliably detect smoke, but also reliably let you know when it is no longer functional.  Smoke detectors work, believe it or not, by having a small amount of low-level radioactivity.  Don't get worried, the radioactivity is mighty low, but it is extremely reliable.  The radioactive portion of the smoke detector is a small sample of a material (it can vary) that has a fairly long half-life (so it works a long time), emits an a low energy Alpha particle (a helium nuclei) and is one decay away from being stable so there is no long, complex decay chain to worry about.  After the Alpha particle is emitted, the remaining material is no longer radioactive.  Just to set your mind at ease, you are not in any harm by being near the radioactive source.  The Alpha particles are stopped by any of the following: a single sheet of paper, the clothes on your back, skin on the palm of your hand, the hair on your head, or a mere 6 mm of plain air etc.  Now if you were to eat and ingest the material, the Alpha particles might damage delicate tissue, but as long as it stays outside the body, they are just not of consequence.  Those Alpha particles are in fact stopped by just a very small number of smoke particles as well.  Basically the smoke detector has a primitive geiger counter separated from the Alpha source by a small gap.  When a smoke particle drifts between the Alpha source and the geiger counter, the Alpha particles get stopped and the alarm goes off.  

This has a number of good safety implications.  First, the Alpha emitter is exceptionally reliable--nothing known to mankind is known to stop or adjust radioactive decay.  Therefore, the Alpha source works day or night rain or shine.  Secondly, when the smoke detector does fail, it does so in a positive way--meaning it goes off.  The upshot of this is that when a smoke detector goes bad, you hear all about it.  Technically, smoke detectors are supposed to be recycled, but many/most just get tossed and when they do, they do so after the Alpha source has mostly decayed away anyway so the decay to background levels happens shortly after the smoke detector fails.  Ultimately, this is a simple, reliable system.  

I suspect that what happened in your situation, and in mine, is that the offending smoke detector was old/bad, the Alpha source had decayed away to the point that the little geiger counter no longer registered any Alpha particles being emitted and interpreted this as a meaning smoke was in the air and needed to go off.  It was really saying it needed to be replaced.  And nothing other than the removal of the offending detector was going to tell the whole-house system to stop shrieking at you.

This last part is all an educated guess, but it is consistent with the way a smoke detector works.  

I hope this is helpful,

Eric

Eric Hanson wrote:D.W.,  I think I know what is going on here.

I once had a similar issue.  I built my house new, and the basic code for new construction around here was to have a wired system, much like the one you have.  And not long after we moved in (maybe a year or so?) the whole house would shriek at us with the painfully loud blast that you described.  There was no smoke and there was no fire.  We were trying to go to bed and we had a small child.  We eventually called an electrician as we had no other idea what to do.  

Once the electrician arrived he simply walked around and inspected the different alarms and eventually removed one and the 20 minutes of ear-piercing screams quit.  He told us that the one smoke detector had gone bad and that they do occasionally need to be replaced.  We thanked him (he did not charge us, but he does get our business now) and he left.

But I did not learn the reason why smoke detectors do this until recently.

So the basic properties of a smoke detector is that it has to not only reliably detect smoke, but also reliably let you know when it is no longer functional.  Smoke detectors work, believe it or not, by having a small amount of low-level radioactivity.  Don't get worried, the radioactivity is mighty low, but it is extremely reliable.  The radioactive portion of the smoke detector is a small sample of a material (it can vary) that has a fairly long half-life (so it works a long time), emits an a low energy Alpha particle (a helium nuclei) and is one decay away from being stable so there is no long, complex decay chain to worry about.  After the Alpha particle is emitted, the remaining material is no longer radioactive.  Just to set your mind at ease, you are not in any harm by being near the radioactive source.  The Alpha particles are stopped by any of the following: a single sheet of paper, the clothes on your back, skin on the palm of your hand, the hair on your head, or a mere 6 mm of plain air etc.  Now if you were to eat and ingest the material, the Alpha particles might damage delicate tissue, but as long as it stays outside the body, they are just not of consequence.  Those Alpha particles are in fact stopped by just a very small number of smoke particles as well.  Basically the smoke detector has a primitive geiger counter separated from the Alpha source by a small gap.  When a smoke particle drifts between the Alpha source and the geiger counter, the Alpha particles get stopped and the alarm goes off.  

This has a number of good safety implications.  First, the Alpha emitter is exceptionally reliable--nothing known to mankind is known to stop or adjust radioactive decay.  Therefore, the Alpha source works day or night sun or shine.  Secondly, when the smoke detector does fail, it does so in a positive way--meaning it goes off.  The upshot of this is that when a smoke detector goes bad, you hear all about it.  Technically, smoke detectors are supposed to be recycled, but many/most just get tossed and when they do, they do so after the Alpha source has mostly decayed away anyway so the decay to background levels happens shortly after the smoke detector fails.  Ultimately, this is a simple, reliable system.  

I suspect that what happened in your situation, and in mine, is that the offending smoke detector was old/bad, the Alpha source had decayed away to the point that the little geiger counter no longer registered any Alpha particles being emitted and interpreted this as a meaning smoke was in the air and needed to go off.  It was really saying it needed to be replaced.  And nothing other than the removal of the offending detector was going to tell the whole-house system to stop shrieking at you.

This last part is all an educated guess, but it is consistent with the way a smoke detector works.  

I hope this is helpful,

Eric

I am a radiation physicist so this post made me smile. You are correct about the particulars! You should totally get an apple for the level of exquisite detail.

Where I think you must be mistaken is the failed device. If the Americium (most common radioisotope in detectors) had decayed away to the point that the electric potential gradient had failed, the detector would just go off constantly until the battery died. But what we have experienced is that the alarm system will go off for a totally random length of time someone between 15 seconds and 3 minutes before mysteriously turning itself off. And it will go a few months between events sometimes.

So we're it a half life issue, I would anticipate the signal would fail permanently and stay failed until the unit in question ran out of battery juice and its internal capacitor discharged.

D.W.,

I did not realize (I must have missed it) that yours is going off randomly.  Mine just started and did not quit until the electrician removed the offending smoke detector from the ceiling.  Perhaps we had different issues going on?

Eric

D.W.,

Also, I appreciate the fact that you recognize my gross simplification of the radioactive (and other) processes involved for the sake of brevity.

Eric

Eric Hanson wrote:D.W.,

Also, I appreciate the fact that you recognize my gross simplification of the radioactive (and other) processes involved for the sake of brevity.

Eric

It's not a gross simplification. You gave an accurate and measured discussion of the safety and nature of alpha emitters.

Charged particles in general have a very short flight time before they interact with matter, and a double charged particles like an alpha is even shorter. That's why the suits you see people wear in nuclear plants are very thin: they aren't really to stop you from getting dose from outside, they are more about preventing contamination so you don't inadvertently ingest radioactive material and get dose to your lungs or alimentary canal which can have very nasty side effects.

Thank you so much for this post! Our fire alarm system is hardwired with our alarm system, and the whole darn thing goes off randomly to the point that we can’t even use our alarm system (and haven’t in a few years). I had someone come out and check it from the company that services it, and they couldn’t “duplicate the problem” either time, so they couldn’t fix it. The only reason that I have the system at all is because it lowers our homeowners’ insurance. It’s totally useless, because I can’t enable the alarm system at all, or the stupid fire alarm will randomly go off. I have to leave it with the error code on there. I’m not sure what to do at this point except to tell them to remove the entire system and shove it if they can’t figure it out. This issue has been going on forever, and when I came looking, I found this old post and was wondering if you had made any progress with your situation?

Lisa Bjones wrote:Thank you so much for this post! Our fire alarm system is hardwired with our alarm system, and the whole darn thing goes off randomly to the point that we can’t even use our alarm system (and haven’t in a few years). I had someone come out and check it from the company that services it, and they couldn’t “duplicate the problem” either time, so they couldn’t fix it. The only reason that I have the system at all is because it lowers our homeowners’ insurance. It’s totally useless, because I can’t enable the alarm system at all, or the stupid fire alarm will randomly go off. I have to leave it with the error code on there. I’m not sure what to do at this point except to tell them to remove the entire system and shove it if they can’t figure it out. This issue has been going on forever, and when I came looking, I found this old post and was wondering if you had made any progress with your situation?

Hey Lisa. Not sure of a solution, but chiming in to say that yeah, that would drive me nuts as well. Hope you can track down the glitch. Luck!

We replaced our hard wired ones when we moved in because they were bat shit crazy like your system.   Now, we just had to replace them all again because they also went insane about 12 years later.

Why!?  So much lost sleep!  

So I asked an inspector guy.

Apparently,  fire and other alarms have something like a 10 year lifespan.  The expiry should be written on the unit and if not, then it is definitely too old and time to upgrade.

Apparently.

Lisa Bjones wrote:Thank you so much for this post! Our fire alarm system is hardwired with our alarm system, and the whole darn thing goes off randomly to the point that we can’t even use our alarm system (and haven’t in a few years). I had someone come out and check it from the company that services it, and they couldn’t “duplicate the problem” either time, so they couldn’t fix it. The only reason that I have the system at all is because it lowers our homeowners’ insurance. It’s totally useless, because I can’t enable the alarm system at all, or the stupid fire alarm will randomly go off. I have to leave it with the error code on there. I’m not sure what to do at this point except to tell them to remove the entire system and shove it if they can’t figure it out. This issue has been going on forever, and when I came looking, I found this old post and was wondering if you had made any progress with your situation?

I had this happen several times over about 5 months, with the last 3 times occurring over 5 days.  I learned that dust build up (and who knows what else) caused the photo eye sensor to trip so I used air in a can spray to blow out each alarm and the problem stopped.  I guess I will do that each year when I swap out the batteries.  
My system is only about 3 years old but I live in a desert and I have a wood stove so dust is everywhere.  I am about 5 months without a problem since I blew out each alarm.  Hopefully this helps.