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Discussion Starter · #1 · (Edited)
Hi,

I just replaced one of my wired smoke alarms on our top floor with wired/battery back up. Flicked the power back on and the the unit started to sound its alarm as did my other unit on the main floor.

1. Do the two units have to be the same? The new unit is battery back up the other unit is just hardwired.

2. Do the units communicate some how together - that's the red wire right? When I unplug the new unit the other unit stops beeping.

3. If i just un connect the red wire I should be good but the units wont communicate? Or, I spend another 20 to have similar units?

Very confused by this. Any help would be appreciated

All the best

PSP
 

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Yes, they will probably need to be the same brand and model. While compatibility is generally addressed in respect to smoke detectors (system smokes), the issue also exists with smoke alarms as you've discovered. For some reason we tend to ignore all those bits of paper come with stuff, and one of those bits should list brands/models it can be connected to.
 

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Grayhair nailed it. I have found this to be the case several times. Best is to be sure that the new smoke detector can be used with the other ones. When mixing brands and even model numbers of the same brands they have been known to "fight" one another.
 

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Hi,

I just replaced one of my wired smoke alarms on our top floor with wired/battery back up. Flicked the power back on and the the unit started to sound its alarm as did my other unit on the main floor.

1. Do the two units have to be the same? The new unit is battery back up the other unit is just hardwired.

2. Do the units communicate some how together - that's the red wire right? When I unplug the new unit the other unit stops beeping.

3. If i just un connect the red wire I should be good but the units wont communicate? Or, I spend another 20 to have similar units?

Very confused by this. Any help would be appreciated

All the best

PSP
Replace all of the smoke alarms with the same model and the problem should go away. Connect the red wire for communication between units.
 

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Discussion Starter · #5 ·
Well I just installed a second new unit - exactly the same as the other - connected the red wires so the units could communicate with each other and no luck - both units sending their alarms. I have had to unconnected the red wire unfortunately - very strange
 

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When you first connected the old and new alarms, it's possible the new one was damaged and is now causing the problem. Or it may have damaged the second new one. It's happened to me.
 

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Well I just installed a second new unit - exactly the same as the other - connected the red wires so the units could communicate with each other and no luck - both units sending their alarms. I have had to unconnected the red wire unfortunately - very strange
Look around for another smoke alarm. I have had customers tell me how many smoke alarms they have only to find one or two additional that they did not notice.

Check the attic and the basement, all bedrooms, hallways...
 

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Just 3?

I have 13 in my house. The packing says that only 12 are supported connected together but it didn't stop the original builder or electrician (I have no idea which trade actually installed them) from hooking up all 13. My friend (an electrical inspector from another state) was at the house a few years back and didn't seem concerned about having 13 hooked together.

They are now about 15 years ago. I had one unit starting to get random alarms (usually in the middle of the night) so I've yanked it for now and I'm looking into replacing all 13.
 

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Just 3?

I have 13 in my house. The packing says that only 12 are supported connected together but it didn't stop the original builder or electrician (I have no idea which trade actually installed them) from hooking up all 13. My friend (an electrical inspector from another state) was at the house a few years back and didn't seem concerned about having 13 hooked together.

They are now about 15 years ago. I had one unit starting to get random alarms (usually in the middle of the night) so I've yanked it for now and I'm looking into replacing all 13.
Your units are 15 years old? If that's the case, you need to replace all of them. Units are supposed to have a max life of 10yrs. Our fire department has an active campaign going to make residents aware of this.
 
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