Electronic Alarms and Home Security Devices - Robert111's smoke alarm questions

Hello:

Boy, I have just finished spending several hours trying to figure out what
is wrong, and am still stumped.
Would really be most appreciative for any thoughts on the following:

My son moved into a 30 year old house a few weeks back.
The house has 3 AC wired-in Rittenhouser smoke alarms.
No real way of knowing, but it wouldn't surprise me if they were originally
put in when the house was built, some 30 years back. But they are possibly
newer ?

The three units apparently are wired to communicate with each other; I guess that if one goes off, they all are supposed to go off. They have a third, Red, wire daisy chaining from one to another.

Didn't really think they did this daisy-chaining concept to fairly recently,
so was a bit surprised to see it.

I just put in 3 new Kidde Model PI 2000 (dual, photoelectric/ionization)
alarms. Also AC wired in. The "seem" to work fine.

But, if I hook up the red wires to daisy chain them together, they all keep
going off, sequentially.

Disconnecting the red wires, reverts them back to apparently normal
operation.

The house is a bit far from me, and won't be down there again for a week or
two.
I mention this, because I "now" think that it might have been a good idea to
put a meter on the red wire and check if there is any voltage on it ?

My undertstanding with the Kidde units, although I am not really sure, is
that there should normally not be any voltage on the red wires (relative to
ground) unless one of the units is tripped.
Should have checked.

Guess I assumed that the daisy chaining "concept" would be the same for the
old units as it is for the new ones ?

Is it possible that these old Rittenhouser units have the red, daisy link,
wire always hooked up to some voltage, or...?

Am I possibly missing anything when I wired them in ?

Any thoughts on what might be the problem, and how to correct it would be most appreciated.

Thanks,
Bob

I'd definitely check for voltage. It is possible that the red traveller is tied to the hot or neutral someplace. It is also possible that the red is actually the hot.

The interconnect smoke design is actually pretty old, so it's not surprising to see in it 1970s construction.

Count your incoming and outgoing wires, there may be another detector hardpoint you didn't know about.

Hello:

Anyone happen to know what voltage is applied to the red
wire that is used to daisy-chain a bunch of 110 V AC wired Kidde smoke detectors together when one of the chain senses smoke and becomes tripped ?

Thanks,
B.

Hello:

Anyone know anything about Rittenhouse 110 V AC wired smoke alarms ?
They are quite old, I believe, and probably not
manufactured anymore, but possibly.

Anybody familiar with them ?
Still made ?

Anyone possibly know the voltage that should appear on wire used for the daisy chaining when one of the units is tripped ?

Thanks,
B.

In the interest of keeping this coherent, I've merged your posts into a single thread. Just click the reply button as opposed to creating a new thread, it's easier for all willing to help.

I've never bothered to measure the interconnect voltage. For modern smokes, it's 9volts or less, because that feature works when the smokes are on backup battery power.

Your Rittenhouse brand is so obscure, that it doesn't show up in any database.

If you put your meter between the interconnect wire and neutral or ground and it shows any voltage at all, then there is something not compatible with modern smoke detector wiring going on.

The interconnect should only exist between the smoke detector points. If you cannot find both ends of the interconnect wire in the first and last smoke detector's box, then there is something unusual going on.