50

If your CO detector were actually detecting CO, it would not chirp. It would sound a continuous, and very, VERY loud alarm you would definitely recognize. The chirping is a universal (as far as I know) method for indicating that it's time to change the battery. This is true for CO and smoke detectors.


30

It's normal for gas and smoke detector batteries to indicate impending failure during the coolest part of the day. The chemical reaction that produces the electrical current is reduced by low temperatures. It's a common occurrence in cold climates, especially in the case of vacation homes that are kept at lower temperatures when not in use. Chances are the ...


22

It likely has to do with the lifetime of the hardware itself. Remember, there's a circuit board and a light source, as well as a detector. Those don't last forever. So the manufacturer certifies the device will work for only 10 years, and then (in some modern units) sets a hard sunset by using an unreplacable battery. In some regards, this solves the ...


16

Considering the low cost of these devices and how deadly CO can be, why wouldn't you want one? That's like saying you don't want a smoke detector because you don't think anything will catch on fire. Just because you don't have any of the items @Steve Jackson mentioned doesn't mean you can't be impacted by CO. For example, maybe a delivery truck is parked ...


16

I was advised by one of the big smoke detector manufacturers that the real issue is voltage. Most battery-operated items will still run, more or less, on a much lower voltage than the nominal voltage on the battery label. That means that the battery can seriously run down and the gadget will still do something, even if it doesn't perform like with a fresh ...


14

Doesn't look like it has a battery. How old is it? There should be a manufacture or expiry date written on the cover. Many older AC powered detectors didn't have backup batteries. That cable you unplugged is the AC power. If it's over 10 years old (or maybe it's 5 years now) it should be replaced anyways. Replace the smoke detector. They aren't expensive....


13

Your detector is a photo sensing type, in other words it has a light source and a light sensitive element and when the light gets blocked by the vapor from the fog machine, it trips the alarm. Other types (ion sensing for combustion gases; heat detecting) would not be tripped by a fog machine. As suggested by @Tyler Durden, blocking the ports should work. ...


11

If you don't have a: Gas or Oil Furnace Gas Refrigerator Gas Clothes Dryer Gas Range Gas Water Heater Gas or Oil Space Heater Fireplace Charcoal Grill Wood-burning Stove Attached Garage (fumes from automobiles and gas-powered lawn mowers) Attached dwelling (fumes from a neighbor with one of these devices) ...then I would say you don't need a carbon ...


11

You can mount them vertically, but they have to be installed 4-12 inches (spacing usually on the instructions) from the ceiling. So it might be better to put in on the column than the beam, depending on how large that beam is. More information from FEMA


11

One consideration is where it's going to be installed. The issue being that some places are more likely to have them go off when they shouldn't. Ionizing can be affected by steam, so has problems if installed right outside a bathroom. They also don't work too well if mounted near moving air (forced air systems, ceiling fans, etc.) Photoelectric are set ...


11

Smoke alarms come in two categories (sometimes combined). Photoelectric and ionization. The lifetime is directly related to the technologies and the environment. The technology limitation of the ionization is that a small amount of a radioactive isotope is used to ionize the air/particle near the electrostatic detector plates. The particles attracted to ...


11

You should use only the batteries recommended by the manufacturer of the detector, and all of the hard-wire w/battery backup models I have experience with expressly forbid the use of rechargeable batteries: For "battery only" models, you might consider the sealed disposable "10 year compliant" models (some jurisdictions require these if you install "...


10

Ionization smoke detectors use a radioisotope to generate a very small electrical current, which when interrupted causes an alarm to sound. These types of alarms use a metal–oxide–semiconductor field-effect transistor (MOSFET) to prevent the alarm from sounding, as long as the tiny current is flowing from the detector. A simple dumbed down version of the ...


10

A low battery is the most common cause of seemingly-random chirps in smoke and CO detectors. Detector end of life is probably the second most common cause. How old is the CO detector? Their lifetime is somewhere in the range of 5-10 years, depending on the make/model (source source source), so if it that old or older, it's best to replace the whole thing.


9

Those wire colors (black, red, green and yellow) are commonly found in the wiring for security systems; smoke detectors that hardwire into security systems typically run on 12VDC or 24VDC, unlike the 120VAC detectors that you generally find at home improvement stores. I'm guessing the wires are stranded instead of solid core (like mains wiring) and of a ...


9

Highly condensed version: studies have shown that the electronics within the detectors fail at a rate of 3% per year. The 10 year mark was chosen based on the cumulative fail rate being over 25%. Sources: Council of Canadian Fire Marshals Fire Commissioners National Fire Protection Agency Underwriters Laboratories There is little to gain for ...


8

I don't think I've seen a smoke detector that only chirps when it's light out, but I'd love to get one if that's the case. Mine always seem to chirp at night (typically because it's colder and batteries fail in the cold). I have seen smoke detectors with a light sensor used in place of a test button, but this typically requires a flashlight shined directly ...


8

Proper test methods depend on type, as there are different technologies employed depending on model. Some use a photo-sensitive element to "see" smoke, others use a radioactive element to detect products of combustion (even invisible ones), others "see" flames with an infrared detector and others detect heat. You should test them exactly according to ...


6

I just posted this on a different thread... but it is useful here also. Ionization detectors are the most prevalent style installed in residences. This is largely due to a lower cost, but they aren't necessarily the best. They have more false positives (nuisance) alarms and are frequently removed or disabled, which does absolutely no good. We had a fatal ...


6

The obvious (but ultimately unhelpful) answer is that the heat/smoke from your cooking is setting off the alarm. So what you have to do is reduce the heat/smoke getting to the alarm. There are a number of things you can do: If you don't have a smoke alarm in the kitchen close the door while cooking. This will stop the fumes reaching the detector. Use the ...


6

According to the guide handed out by my local permitting office, which doesn't cite electrical or fire codes but does detail what they look for: A smoke detector should be placed inside the door of each bedroom 24 inches from the nearest walls or centered on the doorway 24 inches from the wall holding the door. A combination smoke alarm / carbon monoxide ...


6

In our area, local codes made at least one CO detectors mandatory in all condos and rental units. I have had to replace dozens of standard smoke detectors with combo units in hard wired/battery back-up systems. Most every manufacturer makes a CO/Smoke unit that will plug in directly to the existing system. A hard wired replacement is far better than a ...


6

I take it the detector is mounted in the ceiling, and a cut-in 3-O or 4-O (plastic) boxes have a 2 hour fire rating. If this is not enough then you can use metal ceiling octagon box (2 hour fire rating) and use something like a 3M Fire Barrier Moldable Putty Pads. Most companies that deal with fire related caulks and putty make these. A lot of states ...


6

All three wires get capped separately with wire nuts. You need to cap the neutral (white) wire because it can carry current from another part of the circuit. Wrapping the nut in electrical tape is a good idea too. They make nuts that are good for holding a single 12-gauge or 14-gauge wire (the ones I have are dark blue). You don't need to do anything ...


6

As a firefighter that recently battled a large and rapidly moving fire that appears to have started in the attic, I found myself searching the topic of smoke alarms in attics. Though it is a low percentage of structure fires that begin in the attic, they are not isolated incidents. Chimney fires can easily extend into attics as well as HVAC units can ignite ...


6

Not enough information. Are they photoelectric or ionization type, or combo? Ionization alarms generally respond more slowly to smoldering fires, and photoelectric alarms are a bit less sensitive to small amounts of particles that cause false alarms (like bacon smoke or shower steam). Also various manufacturers may produce alarms of various sensitivities. ...


6

Some battery-operated alarms use a radio signal to interconnect so they're all set off together. You should be able to verify/test this using the test button: press it on one, and if the others go off then you know they're interlinked. As far as what's triggering them, there's a few possibilities: Dust in in the sensors. Recent renovations especially can ...


5

The rules are a little different for single family dwellings and apts etc. You can check the NFPA online for latest updates. Little short of time to research it right now, but for single family, the rule of thumb is one smoke detector on each floor. the top of staircases is a good location. At least one of which should be a smoke/CO detector. CO detectors ...


5

Wow- A smoke detector that could cause a fire.. It is very difficult to say It could be a fault in the fire alarm- short circuit that caused the battery to heat up to a cooking point. It could be a chemical fault in the battery where atmospheric pressure and chemical imbalances caused by some impurity during production caused the battery to heat up at a ...


5

I left it off for a time, and did not notice any more water coming from the opening in the ceiling I'll bet there's cold air from the attic coming through that hole, mixing with warm air in the living areas in your house and causing condensation to build up in the smoke detector. You should seal that hole (a) to prevent cold air from moving down, and (b) ...


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