How to trigger alarm from Fire sprinkler flow switch?

We live in a large townhouse with four levela.A few months ago, I replaced 5 of the 8 smoke detectors with Nest Protect 2 detectors since the previous ones were flaky with frequent false alarms, causing us to run up and down four floors in the middle of the night to find the faulty alarm.

Love the Nests, but there’s one problem. We’re in the middle of an inspection of the building and the previous wired detectors were apparently connected somehow to a Potter VSR-SF Flow switch that caused the alarms to sound if the fire sprinkler system is flowing.

Is there a way to have either a separate alarm(s) on the smartthings network connected to the flow switch, or a way to trigger alarms in the Nest smoke detectors?


You could get one of the ST compatible relays and hook it up to the flow switch. You could then get a siren or something, but I don’t think you can set off your Nest Protects through ST.

Many will tell you to never trust your life to ST. In this particular case I for sure wouldn’t trust it yet. Do yourself a favor and get smoke detectors that will work with your system.

Thanks Eric. I don’t think the alarm has to come from the smoke detectors, but that’s how the system was set up to alert of the fire sprinkler system. Personally, I would think that a shower of water coming from the ceiling would be plenty of alert. I really don’t want to replace the Nest Protect detectors with the old non-smart detectors. I trust my Nests more than the old system. We used to get false alarms with the old system, causing us to run up and down four floors to find the problem…

Are there other townhouses in your building, or is yours stand alone?

Hi Keith,
There are other townhouses, connected to ours, cut it’s a separate system. It doesn’t notify the fire department or an alarm company. Our townhouse is four levels with about 2700 sq foot total.

I just talked to an alarm company and they have never seen it set up as it was. Basically, if the fire sprinkler system goes off (heat >155deg), the sprinkler goes off and the Potter flow switch detects the water flow and triggered the smoke detector alarms to go off using the wired relay that the alarms used to talk to each other.

I’m trying to figure out how to set up an alarm that doesn’t go through the smoke detector.

Any advice would be appreciated!

It doesn’t have to be townhouse. Depend on your location. Even new house with sprinkler system requires the flow switch to be tied with your smoke detector. Trust me. You want your detectors to go off if the sprinkler is activated. It’s just not for you but your neighbor as well.
Ask another sprinkler dealer. It’s usually done by an electrician that’s why your sprinkler guy doesn’t know but he should be aware of it. Ask another sprinkler company.
You can tie into it with a smoke detector relay module and a smart close/open contact sensor.

Maybe @N8XD is worried about you killing your neighbors when ST fails.

LOL. Actually, to resolve the problem, I’m going to have to go back to the
old detectors for now until I can find a better option. It’s for the
insurance company. If a fire sprinkler goes off, it needs to sound an alarm
so you know there’s water running in a room of the house. There isn’t any
notification to the fire department or an alarm company, so it feels like a
step back in security for me. Now I’ll no longer get notifications when the
smoke alarms sound when away from the house as I did with Nest.

Still looking for options, but I have to have something running by the end
of the month.