Home Fire Alarm

[William1]

I'm putting in heat (not smoke) detectors in my outbuilding. I have an external strobe/siren wired in. I think I have is right but I want to test.
As I understand it, taking a 9V battery, the positive to the red (of the hardwire three wire) and the battery negative to the black, wired to 120V (Black hot and White Neutral) is the same as if it were actually set off via a detector. AFAIK, a smoke detector operates in the same manner
These are Kidde HD135F

 

[Daren Todd]

The heat detectors i used to install sensed a rise in temperature. So I used to walk around with a hair dryer taped to a pole to test them

 

[North Idaho Wolfman]

The heat detectors i used to install sensed a rise in temperature. So I used to walk around with a hair dryer taped to a pole to test them

You can do it with the Kidde ones you just need a 135F heater.


I have the same detectors in my garage and attic, Inspector thought it was brilliant.
I never tried to run anything external off of the interconnect wire, it's just wired into all the smokes in the house.

 

[Daren Todd]

You can do it with the Kidde ones you just need a 135F heater.


I have the same detectors in my garage and attic, Inspector thought it was brilliant.
I never tried to run anything external off of the interconnect wire, it's just wired into all the smokes in the house.

It's been about 21 years since I've messed with them so I couldn't tell you what brand they were.

They sensed a certain amount of rise in temperature over a short period of time. So a hair dryer on high worked really well for testing them.

The trick was not to hold it too long and have the sensor pop Then you were swapping out the sensor.

It sucked if I was testing them in a school and popped one in the gymnasium. Then I was dragging the big ladder through the school to be able to reach the stupid thing

 

[torch]

The trick was not to hold it too long and have the sensor pop Then you were swapping out the sensor.

Rate-of-rise heat detectors have a large air chamber and a small thermal link in the centre -- usually the link is finned. The chamber has a tiny leak to allow normal temperature variations without false alarms. A quick rise in temperature will cause pressure to rise inside the chamber, triggering the alarm. If the rise is slow (as with a smouldering fire) such that the vent prevents sufficient temperature rise, the thermal link will trigger at the set point (135 F is the most common value, as mentioned, but others are available for use where normal ambient temperatures are higher). Thermal links are often of the fusible type (think melting solder) and therefore not resetable).

The best way to test is with a small concentrated heat source applied to the outer perimeter. A butane powered catalytic heat-shrink torch is perfect. Avoid heating the centre where the fusible link resides. A hair dryer may be too broad and unfocussed.

 

[William1]

Kidde suggests using a hair dryer. I have a heavy duty one (not a heat gut which would melt the detector)The detectors are differential.

I just wanted to test PRIOR to mounting all the detectors

 

[William1]

I spoke with Kidde. 9V battery, Plus to the Red/Interconnect and Negative to the White Neutral will simulate an alarm condition., In addition the 120VAC must be connected so due caution.

 

[William1]

All done. Tested, works as expected, outside alarm and strobe too.

Put in Lithium batteries to get 10+ years between changes. Cheaper than Alkaline cost with annual changes and with my 14'+ ceiling height, less stressful. Had them in the house for five years, every year, I take one out and test, always still 100%.

Google why when a smoke detector battery always fails in the middle of the night and not during the day. Its interesting.