ECN Forum Forums General Topics of the Trade General Discussion Area Smoke/CO2 Detector Combo Units

Anyone have any great knowledge of these god forsaken things?

It seems like every other job I get a "bad" one. We wire our smokes on their own 15 AMP circuit and interconnect them using 14/3 romex. They go on an arc fault breaker. We then use a combo unit in the basement if there are gas mechanicals. Anyone see any problem with that. The combo units are the same manufacturer as the smokes. Typically what we are getting is that when you push the test button at the combo its sets off all the units except itself. Its driving me batty!

Are these things simply that unreliable or are we doing something wrong?

Any thoughts?

Are they UL listed to be used togather with the other units?

What brand and model # smoke/co units?

FireX? I have had the same thing happen and now use BRK and will do so until I have issues with them.

That's what I was lookin' for...yep, they are Firex. I was using BRK but they're so damned expensive. I guess therein lies the phrase "you get what you pay for".

There was a long run with the Firex CO/smokes having problems. I'd get a bad one every fourth or fifth one.
They have improved them and changed the p/n to 12000 from whatever it was and I have seen MUCH less issues with them.

Found out from Firex that some of the issues are actually misunderstandings. If you push the test buttom of a smoke detector or a smoke/co2 it will set off all of the alarms in the house except for itself. So its not actually "bad", its just working the way they've designed it to. I guess then to be sure you have to go to each alarm and push the test button. Probably should do that anyhow, right?

Combo smoke/CO devices are a bad idea to begin with; smoke rises CO/CO2 is heavier than air so it sinks. I'd never use them.

Derater is right, combo units suck, they are more costly than individual smoke and CO2, and the CO2 detector should be down by the furnace or whatever the heat is in the house, halfway down the wall. Have to ask, how does the 14-3 work on an arc fault? Won't that trip the breaker?

daffy03221:

Welcome to ECN!

In this case, the 14/3 is most likely wired as Black = hot, white = neutral RED = "signal" (or "interconnect") which is a low-voltage link between units.

So this would not be the dreaded multi-wire application. Thus no issue at all with the even more dreaded arc-faults.