Hard-Wired Smoke/CO Detector Troubleshooting And Installation 

Great troubleshooting, and I'm glad my video was helpful!

Yeah, using grounds or neutrals to make a test loop can be useful too, but that can't be used in every situation. The extension cord idea came to me in a moment of frustration and it's a good trick to have up your sleeve.

The 80s were a long time ago! You really are supposed to change them out every 10 years or so, and the new ones with the combination of smoke and CO are actually improved. They also have a voice command now, so it will let you know if the problem is smoke or CO. The carbon monoxide is no joke--you go to sleep at night and you don't get up in the morning. Ever!

@@enduringcharm We'll have to look in to that. I'd love to have smoke/co in tandem. Certainly affordable enough. Thank you.

@@enduringcharm is the dectetor connected with switch?

@godwin usman There should be no switch in the circuit.

Yes, a tone generator can work for some people--I used to use them for telephone circuits back in the day. Today, though, my hearing is pretty badly damaged for a number of reasons and I wouldn't be able to hear the tone.

I could have been clearer on that point. What I was testing for was double voltage, or a 240 volt reading between the red and black. On more than one occasion I've found where somebody miswired cables within a circuit, and the red wire is often the culprit. Sometimes two cables go through a box fed by different breakers and somebody ties them together. I did a bath remodel one time where two breakers were feeding a single cable! That was a head scratcher! So in this case I was concerned that perhaps somebody had used the red wire for another purpose or wired it where it shouldn't go. I was speculating that maybe that would be the reason the boxes were abandoned, since that would probably cook the detectors. Since I found zero across the red and black I knew that only one breaker was feeding the circuit and I also I knew that the red wire was not shorted or tied to neutral or ground. If I had found 240v I would have looked for a second source of power tied in somewhere. If I had found 120v I would have looked for where the red wire was connected or shorted to ground or neutral.

Yeah, I can understand your frustration. It is a fire code requirement for the detectors to be hard-wired and linked in many areas, though. In NJ, where I live and work, when a home is sold to a new owner, the municipality checks the detectors and issues a CO. Honestly, I think the only reason this example in the video wasn't flagged is because during covid a lot of the inspections just weren't getting done. Incidentally, for your situation there is usually a light or other indicator when a detector has a problem. If you have ten, that's a lot of checking for sure!

The shower cap is included for use during construction. Drywall dust and paint overspray can clog up and ruin the sensor inside the unit. Ideally the detectors are removed during work, but during new construction one trade won't touch the work of another trade, so they include a shower cap to protect the units while work is being done.

Ha! Yes, I spent a little time in the Navy. Of course, it's a myth that anything can be made sailor-proof!

I'm not sure I follow your question--are you hoping to disconnect the hard wired smoke detectors in other areas of your house from the one in your bedroom?

If we are talking about a single, AC powered detector then at a minimum you should have the hot (black) wire connected and the neutral (white) wire connected. Without both connected it should not work unless it is running on backup battery power or the bare wire ground was improperly used. It is possible the white wire just came loose if it was not well connected in the first place.

It's difficult to offer advice without seeing the problem in person. One thing I don't know is the meaning of the green LED for the detector--does your manual have any advice about that? If the detector is getting power, and if pushing the test button on the detector also sets off the other ones in the house, then maybe there isn't a problem with the wiring. Maybe the green light pertains to the status of the backup battery, for example. Did you have the backup battery removed when you were doing your testing?

@@enduringcharm I tested all of them connected with battery first with the breaker off and all communicated then put breaker on and created smoke to test and that too was successful. Then walked to each unit to take my photo of completion and notices the green led was lit only on 2. Did a swap with one that the led was lit green and it didnt light at this location which is what makes no sense as the led is internal. And I have the battery still installed. Didn't focus on that during initial install as I had a bright light shining there so wouldn't see it anyways. But maybe there still is a wiring issue. I am going back tomorrow I will pull the battery out at that location and and see if it chirps or sets off the detector while it's still hardwired if not then there has to be some issue with the wiring. I'll check the voltage too. Thx for the response as it gets me moving mentally to troubleshoot. The owner did say that location came from a different source a light so the power is not in series. Only the red wire is in series. I'll update there may be others who run into old setups and need to see how other solved.

Ha! Well, I hope it isn't the same person wreaking havoc somewhere else now!

Well, there are several possibilities. One, you may not have made a good connection with the signal wire when you installed the new unit. You can pull that apart and check. Two, it is possible you have a bad signal wire, although if it worked with the old unit that is unlikely. Three, it is plausible that the old and new units are not compatible, although most are interoperable. In any case, the old units from 2004 are eight years overdue for replacement and really can't be trusted anymore. I surmise you are a young adult living with the 'rents or trying to keep them safe in their own house? The best approach would be just to replace all of the old detectors with combo smoke/CO detectors. You can buy them in bulk packs of various numbers and maybe it could be an early Christmas or Hanukkah gift?

@@enduringcharm Thinking it might either be a bad connector in the new unit plug wire itself, there is power going through the wire to the new unit tested it but don't know if that interconnector wire is communicating with the new unit, if that makes any sense. ha . If the older units are 18 years old and different wiring connections to them for the interconnector wire I assume that would be a issues with both the new and old ones communicating with each other, But going to take the new unit back and get another one thinking I might go with either the same type of smoke alarm unit because yes its cheaper and yes adult living with parents which is another story in itself. The other concern is getting at least three smoke and CO unit for each level of the home one in the ulitity room, one by the stairs and the other in the family room but one parent is wanting portable plugs-ins now for CO. MMM Decisions! Thanks for responding too Much Appreciate!

The plug in style CO detectors are okay too. The Kidde Nighthawk is one example. But, it doesn't cost much more to get a combined smoke/co unit, and that should set off the whole house if needed. As you saw in my video, you can test the signal wire if need be, but if none of the other units are working when the new unit is tested then it's more likely to be the new unit or the connection near the new unit.

Many hardwired smoke/co alarms do have a battery backup. Typically there is a little door on the edge of the alarm which slides or pops open to expose the battery. The hissing sound is not normal, and may indicate excessive dirt or dust in the unit or possibly the unit is just due for replacement. The rule of thumb is a ten year lifespan, and you can check for a date printed or stamped on the unit.

Without being there it's hard for me to tell, but the neutral is definitely needed to complete the circuit. Possibly somebody disconnected the first wire they grabbed if the detectors were going off. You can put a meter on the white and black wires and see if you get 120 volts. If you do, then you can reconnect the wires as they should be and test your detectors.

@@enduringcharm problem is no one was messing with the wires, the neutral wire just came undone

That's also possible if the original installation was poorly done. The wires should be twisted together with a pair of lineman pliers (or similar) BEFORE the wire nut is used. If the loose connection is the stranded copper wire with the solid wire, then perhaps the wrong size wire nut was used.