Should I replace old smoke detectors?


Old 01-03-06, 12:18 PM
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Should I replace old smoke detectors?

Sorry for the double post...

I just bought a home that is about 9 years old. It's got hardwired smoke detectors that I have not found a lot of info on the web about (They are Firex and the only identifying number on them is 120-538b).

I'm pretty good with electric and just replacing them seems pretty easy. They have a load, a neutral and what I beleive to be is the common wire they all trip with.

My questions is this: 1) They're kinda old. Should I replace them? and 2) if I go with a newer model, say a Kidde, I should just be able to hook black to black, white to white and red/yellow to red/yellow, no? ANy suggestions?

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Old 01-03-06, 12:30 PM
Join Date: Sep 2000
Location: United States
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1) The lifespan of a smoke detector is 10 years. Yes, replace them.

2) To ensure that the interconnect works, all the ones you buy to replace them must be the same make and model. Places like Home Depot give a price break on a box of six (if you need six). There's no special trick to replace them. Just follow the directions. Be sure to turn off the breaker before you begin.
Old 01-03-06, 12:32 PM
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Location: Central New York State
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You can replace the smoke detectors if you want to at this time. Firex is a common brand. Smoke detectors do need to be replaced, with the usual time being 10 to 15 years.

The three wires are as you suggest, although the proper term is line, not load. The third wire interconnects the devices so that when one activates they all activate. Using the term common for the third wire may confuse some people.

If you do replace them, make sure that you replace all of them at the same time with the same brand. No, I donít mean that you have to replace them Firex, although you can if you want. What I mean is that all of the units must be compatible with each other or they may not all activate at the same time. The easiest way to have them all compatible is to buy the same make and model for every location.
Old 01-03-06, 12:45 PM
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Yeah, my terminology may not be the best, but you understood what I meant That's kind of what I figured - thanks for the confirmation.

I've got an outlet-based CO detector, and am interested, if I have to repalce the lot of them, in getting a hardwired one or 2. My equipment room is in the basement, with only 1 detector NOT inside the equipment room (in the hallway) I would definately place a CO detector there, should I also put one in the upstairs hallway (all the bedrooms have regular detectors, but a single CO in the hall should suffice, no? or is that overkill?)

The only source of CO is the furnace, right? no fireplace, but a gas stove. Will one in the basement be good enough?

Also, if i choose to replace them all (about 10 of them), do I need to dispose of them in any special way? Don't that have some radioactive stuff in them??

Lastly - any recomendation on a reputable brand? I have Kidee in my townhome, and am happy with them. Any one better than the other?

Old 01-03-06, 01:00 PM
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I have no particular brand preference. I would probably stick with a brand I have hard of rather than one I haven't, but that's me.

They do make hardwired CO detectors. They even make combination CO and smoke detectors. I donít know, however, if these units are able to be interconnected.

CO detectors are recommended on every level of your house. They should be placed outside the sleeping areas and not in close proximity to sources of CO. CO is a byproduct of combustion. This means that your furnace (gas, oil, or propane), your fireplace, your gas dryer, and yes even your gas stove/oven produce CO. (The amounts produced by your stove are minimal.)

CO mixes very easily with air (which is one reason it's problem). For this reason CO detectors do not need to be placed on or near the ceiling like smoke detectors do.
Old 01-03-06, 01:51 PM
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while on this subject of detectors

do these hardwired detectors typically require a J box with each? Or direct wired or?? Did I read before that you should NOT use the BR AFCI to feed these?
Old 01-03-06, 02:10 PM
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If you can, you can get a newer version of the existing smokes, that wat you jsut need pop off the old, and pop on the new, using the same mounting ring and wiring connector usually.

Bedroom smokes count for AFCI requirement.

When you rough in, you use a standard round/octagon light box.
They need a J-Box like any other line connected equipment.
Old 01-03-06, 02:25 PM
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Originally Posted by telecom guy
Did I read before that you should NOT use the BR AFCI to feed these?
This is a local issue. Here are some of the common codes I have heard for different regions:

1) Smokes must be on an AFCI circuit.
2) Smokes may be on an AFCI circuit.
3) Smokes must be on a dedicated circuit
4) Smokes must be on a circuit with a commonly used light fixture.

As you can see, this varies a lot as some areas require what others explicitly prohibit. My personal preference is to follow #2 and #4, but it's entirely up to your AHJ as the NEC specifies #1.
Old 01-03-06, 02:30 PM
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The NEC requires AFCI for bedroom smoke detectors. So, if you live in the U.S., and if you are rewiring your bedroom or for new construction, and unless your area has specifically modified this requirement, smoke detectors in bedrooms must be AFCI protected. Of course, if you're just replacing one smoke detector with another and not rewiring the bedroom, your non-AFCI circuit is grandfathered. And since all smoke detectors must be interconnected, your non-bedroom smoke detectors will end up being AFCI protected too.
Old 01-03-06, 04:23 PM
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I didn't find a direct cross reference for your model . The important consideration for replacement of interconnected alarms is the interconnect voltage. Older systems used the line voltage; newer ones used low voltage. If you replace ALL your alarms, it doesn't matter. You might need to install the new pigtail which will be included. The only current Firex which uses line voltage interconnect is the model 0428. If necessary, call Maple Chase (InvenSys) @ 800-304-3563. They will tell you what unit is compatible.

Again, if you install ALL NEW units, which is definitely recommended, it doesn't matter. According to the NFPA, of all smoke alarms 10 years old, less than 50% will be operational.

Last edited by 594tough; 01-03-06 at 09:13 PM. Reason: spelling
Old 01-03-06, 05:06 PM
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Thanks for all the replies. The home is about 9 years old and has hardwired smokes. Poking around the breaker box, I found the breaker for the circuit. I'm going to assume that since it's a development, and all the houses were built by the same company, they are to code and all interconnected.

Personally, I like companies that have websites that you can download info from. Kidde is one such company and if anyone has any negative feedback, please let me know.

The smokes have a 3 wire snap in connector that I'm going to guess is proprietary to Firex. I will probably head down to Home Cheapo and pick up a contractor pack and coupla CO smokes as well. I have the Kidde's that talk now, so maybe if I'm feeling lonely, I'll hack it and make it talk dirty to me.

Thanks again for the feedback!

Last edited by DaGbyte; 01-03-06 at 05:54 PM.
Old 01-03-06, 10:20 PM
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I did not see an answer to your question about disposal. Smoke detectors do contain a small amount of radioactive material and should be disposed of properly. Check with your local landfill people.
When you use a combination CO/smoke detector in each hallway (of the same brand as the other interconnected smoke detectors), if one of them senses CO and alarms, then all of your interconnected detectors will also alarm, usually with a different sound than for the alarm for smoke.

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