Smoke alarm installation - alarm going off after AC back on

[wtt1971]

Hello,

I bought 5 Kidde i12080 smoke alarms to replace 5 old Firex FXW-R in my house. In order to install the first one, I turned off the circuit breaker dedicated for all smoke alarms and installed one i12080 (connecting the three wires: black, white and red).

I decided to test only the one alarm I had just installed (4 FXW-R are still in place), and when I turned the circuit breaker on, the i12080 went off beeping like smoke had been detected, non-stop . I turned the breaker off and the alarm still beeped for 5 more times and during that time the light on the alarm was also on (steady).

My guess is that I should have replaced all alarms at the same time, given I have one i12080 connected to 4 FXW-R, via the red wire, but this is just as guess as to why the alarm went off when the breaker was on. I believe that the alarm shouldn't have made any noises when AC power was on.

Please advise. Thanks!

 

[dlester]

Hi dont mean to undermine if you know your stuff but youll have 240v red - live, black neutral and white will be a switched signal between your detectors. Have you wired the first one of the radial circuit or is it in the middle or end of the circuit?

id expect the 1st in line to have a red + black in, then red, black and white out. If you still have problems and you have made sure no wires are mixed up then. Ditch the white cables put them on a connector and just wire red and black to the new smoke head. If it still goes off youve got a faulty head

 

[wtt1971]

Hi dlester, the electric schema for the alarm is as follows:
white - neutral
black - live
red - used to interconnect alarms (if one detects a smoke condition, all of them goes off).

And the whole house has 120V, not a single point has 240V.
Thanks

 

[bernardgreen]

This thread relates to equipment in the USA where the colour codes are


WHITE neutral
BLACK live 120 volt

and therefor the information is NOT applicable to installations in the UK

 

[dlester]

Ok my apologise. I should have noticed the flag symbol. Disregard the colour codes and 240v

still wire it up without your red interconnection and see if it goes off. If it doesnt you know its not the new head. It could be a polarity issue on the interconnection.

 

[sparkymarka]

never mix different brands of interlinkable smoke alarms as they may not be compatable and may damage the unit

 

[wtt1971]

Just posting the solution here: when I had different alarms interconnected, the old ones went off because they didn't recognize the signal coming from the new one.

 

[dlester]

Well done.