Smoke detector idea

[AOD]

I have a forced air wood stove with an outlet duct coming straight off the top of the stove. I want to install a furnace fan/limit control in this duct to automatically control the blower. This control also has a set of limit contacts (normally closed, opens on excessive temp. increase) that is designed to shut down a gas or oil furnace should it get too hot. I was thinking of wiring this switch in series with my whole house smoke detectors. I know when I turn the breaker off that feeds them the automatically go off on battery. This switch would do the same thing, should the stove overheat, it would cut the power to them and they would go off on battery, which would wake me up and alert me to a stove problem. What do you guys think? It is probably not code to do anything "custom" to a hardwired smoke detector system, but I really don't care, it would give me some peace of mind.

 

[KsWoodsMan]

An alarm of some type sounds like a good idea . Switching off the supply for the smokedetectors doesnt.

Many electonic parts outlets carry piezo buzzers that could be used and require only low voltage to work. Radio Shack used to have scads of this type of buzzer for hobby projects. Most of them will operate on 3-12 VDC.

 

[AOD]

Well cutting the power to the smoke detectors is the only way I can think of to make them go off the way I want them to. They are designed to work in a power outage on their own internal batteries, and if they go off I can remedy the problem and then the power will be restored to them (it's an auto reset type of switch, I do not have to manually push a reset button)

 

[Marc]

Wait a sec... everytime your smoke detectors lose their AC feed they go into alarm? Am I not reading something right here?

 

[AOD]

Wait a sec... everytime your smoke detectors lose their AC feed they go into alarm? Am I not reading something right here?

Yup, thats how they work. I found out once when I turned off that breaker by accident.

 

[Marc]

Yup, thats how they work. I found out once when I turned off that breaker by accident.

How old are they? From what I know, most if not all modern smoke detectors wired into AC with battery backups do not go into alarm during a power outage, they seamlessly switch to their battery backup.

The idea being, they don't wake you up in the middle of the night because of a power outage, and have the occupants mistakenly thinking there's a fire (or at least smoke).

The communication between the detectors is typically the red wire, and is a simple 9VDC signal.

I'd advise against using the detectors for anything besides smoke detection.

I'd also advise you have the wiring checked on the detectors. If they are in fact wired correctly, I'd buy new ones that don't act like that. It's a pretty useless feature for your smoke detectors to alarm everytime you lose power, and could lead to a dangerously confusing situation or a "cry wolf" response.

 

[AOD]

Well they are only 2 years old and were installed by competent electricians from a reputable company. If I do not want to interrupt the power to them how can I activate them some other way aside from the stove setting the house on fire.

 

[KsWoodsMan]

From earlier

Many electonic parts outlets carry piezo buzzers that could be used and require only low voltage to work. Radio Shack used to have scads of this type of buzzer for hobby projects. Most of them will operate on 3-12 VDC.

Use a high limit switch to turn on the power to a buzzer powered by a couple of batteries. All of it lowvoltage low current not much chance of electrocution or uncontrolled fire.

 

[Wirenut2266]

UMMM somethin's not right:

No Way: Your Smokes should 'chirp" every 2-5 minutes letting you know of power loss, that's it. They should signal an alarm only when smoke is present. Come on, think about it! Are you serious! My wife even knows this isn't correct. Kill the power to the circuit, look for latched "red" led on unit, that is the one signaling an alarm. Power circuit back up, and replace bad unit. Your idea won't work if smoke alarm circuit is working properly.........I did say "IF"

Good luck.......

 

[AOD]

Well just an idea.

I am thinking of some way to easily make an alarm if my wood stove overheats drastically, and the smoke detectors came to mind because they are all through the house and loud enough to wake me up.

 

[Wirenut2266]

AO: Nuttin wrong with trying I guess, but "that" particular one, not one of your best, sorry. Anyway, get your smokes fixed asap, they do no good if circuit is F'ed up. Radio shack will prolly be able to hook you up. I beleive they have heat sensors that are battery operated that go off like a old school bell. Do internet search, sounds very simple for what your asking.....Bruce


Grainger.com Search keyword: Heat Detector

P.S.: Should be able to purchase heat detector and tie into smoke alarm circuit, then all will still go into alarm mode. Hopefully can still get at one of detectors wiring easily.......

 

[AOD]

What does the red wire do? If I broke that circuit with the limit switch would it make the detectors go off?

 

[Wirenut2266]

I won't yell or call you names but here goes; Black and white are your 120 volts to power alarm circuit, period. Red is the "signal" wire which sends the low voltage signal to all alarms and they go off. There is no breaking the cicuit, period. Be very careful messing with these guys, think it through, call a fellow wirenut (Electrician) to give you ideas on your situation. They will give you safe, legal ideas without compromising safety......PLEASE

NO DO NOT PUT A LIMIT SWITCH IN CIRCUIT, IT WILL NOT WORK!

What does the red wire do? If I broke that circuit with the limit switch would it make the detectors go off?

 

[AOD]

Allright, fine, fine. I wont mess with the wiring. Just an idea to have an alarm if the stove is overheating.

 

[Marc]

Allright, fine, fine. I wont mess with the wiring. Just an idea to have an alarm if the stove is overheating.

I don't think anyone here thought that the concept of an overheating alarm was a bad idea at all. On the contrary, I'd be very happy to see you install something like that, if it's reliable and works as intended.

It was just the proposed execution of the idea that needs a little reworking. Don't let that set back stop you. The mark of a good home tinkerer is perseverance.

 

[buildmyown]

What about using a doorbell they also work off of low voltage. Mount the part of the doorbell that has the chimes in it in your bedroom run the wires from the contacts on the limit switch to chime box. If you should ever have a problem the contacts will open and send power to the doorbell.

Just thinking out loud here.

 

[Jkebxjunke]

all you need is a simple thermostat, low voltage wire, a buzzer/bell/noisemaker of some kind, a battery or a transformer. ... Put thermostat where you want to monitor temperature.. run wire to where you want nose making device and put transformer inline... when circuit is closed by high temp... DING.

for thermostat... better yet... get a thermalarm (Thermalarm II - its a normally open and closes on temp rise or fall) device... it is a termerature monitoring device that can monitor high AND low temps... so it could also alert you if it got too cold.

 

[Jkebxjunke]

I don't think anyone here thought that the concept of an overheating alarm was a bad idea at all. On the contrary, I'd be very happy to see you install something like that, if it's reliable and works as intended.

It was just the proposed execution of the idea that needs a little reworking. Don't let that set back stop you. The mark of a good home tinkerer is perseverance.

actually the concept of an overheating alarm has been around for quite some time.. just not really in the home market... now in the agricultural sector it has been around for quite some time.... in chicken houses ( which I am familiar with) we use these units called Thermalarms that can be set to alarm on both high and low temp and they are settable. they work quite well and we have been using them for as long as my family has been growing chickens ( bout 30 years) and I believe they were used long before.

 

[Booshcat]

Radio Shack used to sell an alarm that would fire a relay and close/open contacts, and even dial your phone and tell you the temperature.

 

[Jkebxjunke]

Radio Shack used to sell an alarm that would fire a relay and close/open contacts, and even dial your phone and tell you the temperature.

unfortunately radioshaft has gotten away from a lot of that and gone to selling cell phones and computer accessories.