I scorched a pot making applesauce with the last of my apples. I was upstairs on the computer and had set a timer for 15 minutes and had it with me.

Later after the clean-up, I checked the timer. It was stuck at about 2 minutes. It was pretty old, so I thought its 'innards' had become corroded a bit, creating friction.

I wondered why the smoke alarm had not gone off. Then I remembered that it was over ten years old, which is when the manufactured recommended a replacement.

So I went to Canadian Tire Store and bought
(1) a new timer, and
(2) a package of three smoke alarms including batteries.

I tried the timer that same day. Didn't work. Even after an hour, it hadn't make it to the 5-minute mark where it ought to have sounded.

So I repacked it to return. Noticed on the box: "Made in China".

Today I set about to install the three smoke alarms. I installed the batteries and pressed the 'test' button. Nice loud sound on 2, intermittent weak sound on the third. I reinstalled the battery in the third, making sure the contacts were good.

Then I did the second, more important test. I put a piece of aluminum foil on a stove burner, and sprinkled sugar on it, and turned it on. The three alarms were at a distance of three feet (horizontal) from the burner, and above-my-head at arm's length above the floor, resting in the prescribed position, with sensor on the 'bottom' side, facing the room. They were on an ornamental shelf I have, the shelf itself a metal rack with large perforations -- sort of like very coarse mesh. The sensors themselves were not obstructed by any part of the shelf: they were exposed to air.

Then I turned on the burner. A lot of smoke was produced. Nothing from the alarms. Added more sugar. Lots more smoke. One alarm sounded. I set it aside.

I got a dry twig and a candle, and lit the candle and made a smudge out of the twig. I held the smoking twig about 3 feet below the detectors. Nothing.

I re-ignited it, to create a denser smudge. One of the alarms went off when the smudge was held directly below them, about a foot away. I removed it, and decided to test the third to see if I could get it to sound at all.

Even with the smudge touching the sensor opening, no alarm sounded.

Then I carefully read the instructions.

It is an ionization-type:

Works best with hot, fast fires.

For smoke detection, photoelectric works best.

So now I know I need to buy two sets: ionization and photoelectric.

But because the third one didn't work, even though the burning stick was hot enough and close enough to slightly melt the plastic cover, I'm packing them up, too, to return. And guess what. "Made in China".

I hope I don't get grief from Canadian Tire because the third one shows smoke damage on the sensor itself.

Because that would mean that they intend to put it right back on the shelf, for re-sale to someone who relies only on the 'test' button to assure them the damn thing works.

So I thought I'd warn you.

You'd best have two types, and
You'd best not rely only on pressing a button to test the device.

Oh. And best to look for a manufacturer a little more used to our North American safety standards. North American, because European electrics drive on the wrong side of the road. Shame. They have excellent standards over there.

Everything you wanted to know about smoke detectors and then some.

Smoke

Smokes are usually so sensitive that they will go off even before YOU can see or smell the smoke. They use a Precision smoke generator to test the units in my building. They tell me that they get dirty inside after a time and lower their sensitivity and need to be replaced.

My wife test ours at least once a week. All she does is cook dinner.

That'll teach me to buy a cheap import! I'm returning them today or tomorrow, and getting better quality. Thank you for the reference.

I'm puzzled by the 'block of butter' device. In my house, there would me mice there in about five minutes!

I have a Kidde 0910 smoke alarm which has a long life battery (good for 10 years)and Ok, its not the Cheapest but it makes a loud noise and is well put together.
http://tinyurl.com/Kidde-0910
Cost from this store just $22.59 (US) Are better than $38 elsewhere
Another Brand is EI from Ireland we have 3 of these (EI.100BN) that kick off a Racket (Use Regular batteries) Bit over sensitive though
Steam out of the Bath does trip them

www.eielectronics.com/ei100B.php (makers site)
These are $7 to $8.They are not exported

We have a Sirius Mach I Smoke detector - she has been trained to bark loudly and repeatedly at the first whiff of smoke (excluding cigarette smoke, will growl at pot smoke )

We 'tested' it out by allowing a slow short work its magic on an outlet - well it just happened, didn't set it up that way - before I could see smoke coming out of the outlet the Sirius Mach I was Loudly barking and facing the offending outlet.

Our First Alert Smoke Detector sat there quietly. It was closer than the Sirius Mach I.

I guess Mom Nature does a better job at smoke detectors than man.....