Only one horn/strobe, and it was just beeping

[480sparky]

A couple days ago, I started a small commercial job in a retail store adding some receps and phones that were missed during the design phase. The only thing I had done so far the first morning was to look at the panel to locate the circuit I was going to work on when I heard a beeping sound.

I walked out on to the sales floor, and a single horn/strobe was beeping. No flash, just the beep.... and every 15-20 seconds instead of wailing like normal. And none of the others seemed to be doing anything. The owner had a key to the electrical room, so I took it and checked out the FA panel.

Silent Knight. Panel was good.... showed no trouble or alarms. The monitoring company had not gotten any notification of any problems. But the h/s would beep for ? second about every 15-20 seconds.

Being a new store (opened a couple weeks ago), I told the owner to contact whoever installed the FA system.

I noticed the h/s was gone by the time I finished yesterday, so someone had been on-site to troubleshoot it. But I'm curious as to why a single horn/strobe would act that way? Bad unit? Bum board in the panel? Poltergeists?

 

[peter d]

Some horn strobes will beep intermittently if they are wired backwards ie polarity is not observed since FA circuits are DC. The supervising current is causing the beeping.

I know this from first hand experience.

 

[480sparky]

If reverse polarity were the case, the technician didn't need to remove the unit. Just swap the wires and call it done.

I just got back there from stopping by (and picking up a check as well..... hooray!) and it's still missing.

 

[MisterCMK]

It could have been a bad device as well.

 

[480sparky]

I'm just seeing if there's a concensus about a cause, as I've never encountered this before and would just like to know in case I live long enough to run into it again.

 

[hillbilly1]

Usually a horn wired backwards, will trip the trouble signal on the F/A controller.

 

[480sparky]

Usually a horn wired backwards, will trip the trouble signal on the F/A controller.

That's the weird thing.... it didn't. Nor was the strobe flashing.... just the horn going off for ? second every 15-20 seconds.

 

[peter d]

If reverse polarity were the case, the technician didn't need to remove the unit. Just swap the wires and call it done.

Sorry for suggesting a likely cause for this problem. :roll:

I forgot who asked the question. :roll:

 

[iwire]

Sorry for suggesting a likely cause for this problem. :roll:

I forgot who asked the question. :roll:

It's OK I was going to say my first guess would be wired backward and if not that the diode in the unit is broken or in backwards.

The supervisory current can cause intermittent chirps but I know Pete knows that.

If reverse polarity were the case, the technician didn't need to remove the unit. Just swap the wires and call it done.

Of course it could also be that the technician was not that sharp and did not verify the polarity of the field wiring and is replacing a H/S that is fine.

 

[480sparky]

...Of course it could also be that the technician was not that sharp and did not verify the polarity of the field wiring and is replacing a H/S that is fine.

True. Not everyone is as smart as Peter.

 

[peter d]

True. Not everyone is as smart as Peter.

:roll: :roll:

Like this is such a rocket science problem to begin with. It's either wired backwards or a bad h/s. As I said earlier I have first hand experience because I wired a h/s backwards once and got the same result.

 

[480sparky]

:roll: :roll:

Like this is such a rocket science problem to begin with. It's either wired backwards or a bad h/s. As I said earlier I have first hand experience because I wired a h/s backwards once and got the same result.

"D$(#*t, Smithers. This isn't rocket science.... it's brain surgery!"

 

[peter d]

I'm surprised this tech doesn't have a replacement horn strobe on his truck. I know there are all kinds out there but if he's used to installing the same system he ought to have a few of the common kinds he uses on his service vehicle.

 

[peter d]

"D$(#*t, Smithers. This isn't rocket science.... it's brain surgery!"

Of course, electrical work requires a PhD minimum.

 

[480sparky]

Of course, electrical work requires a PhD minimum.

If it was easy, the plumber would do it.:roll:

 

[nhfire77]

Possibly dumb question, was it a fire horn strobe? I assume it was the same color as the others and it said fire. In no way am I questioning your intelligence/abilities. Horn strobes are used for other things, but wouldn't safe fire on them. I'm wondering if it could have been something else, only because it was the only one.

 

[480sparky]

Possibly dumb question, was it a fire horn strobe? I assume it was the same color as the others and it said fire. In no way am I questioning your intelligence/abilities. Horn strobes are used for other things, but wouldn't safe fire on them. I'm wondering if it could have been something else, only because it was the only one.

Fire alarm. The burglar alarm was a totally different system. The FA panel was in the electrical room, marked with the tenants name and unit #. The burglar alarm was in the tenant space and only had motions sensors.

 

[ivsenroute]

:roll: :roll:

Like this is such a rocket science problem to begin with. It's either wired backwards or a bad h/s. As I said earlier I have first hand experience because I wired a h/s backwards once and got the same result.

But did it cause a trouble alarm?

 

[peter d]

But did it cause a trouble alarm?

No, nor is there any reason why it should. Wiring an FA device backwards only causes a problem for the device itself, not the entire loop.

 

[Mgraw]

I don,t know about all horn/strobe devices but the ones I have installed have three terminals, one negative and two positives. If you put the negative on one of the positives and one of the positives on the negative how does this not affect the whole loop.