Kidde smokers run amuk

[thinwater]

Originally Posted by CaptTom

Usually on a boat, false smoke alarms are due to Hydrogen Sulfide from battery charging. Were you plugged in at the time?

Another possibility is condensation inside the detector. We all know how condensation can form on the hull or anything metal when temperatures drop. Even if that doesn't set it off, it can cause dust to stick to the detector.

It's never good to ignore an alarm, but the fact is there are a number of causes for false alarms. The trick is being sure you know the cause.

Hydrogen, not hydrogen sulfide (batteries also do not give off hydrogen sulfide, only H2 and H2SO4). See post 6.

[CaptTom]

Originally Posted by thinwater

Hydrogen, not hydrogen sulfide (batteries also do not give off hydrogen sulfide, only H2 and H2SO4). See post 6.

Live and learn! I knew about Hydrogen, I've watched it bubble out. So what is that "rotten egg" smell when a battery is overcharging? I just assumed that was what was causing the detector to alarm. Hydrogen rises in air. I know at least once I've heard the CO detector go off due to battery charging, when the detector wasn't on the overhead, or near or above the battery compartment, so it wouldn't have "seen" much Hydrogen.

[boatpoker]

Originally Posted by CaptTom

I know at least once I've heard the CO detector go off due to battery charging, when the detector wasn't on the overhead, or near or above the battery compartment, so it wouldn't have "seen" much Hydrogen.

How much does it need to "see" ?

[capn_billl]

Originally Posted by thinwater

CO sensors with alarm on many other gases, because that is how the technology works. The cross interferences are well known.


They are very sensitive to hydrogen gas, a common source of "false alarms" on boats that have been closed up.


https://sps-support.honeywell.com/s/...sitivity-to-H2


https://www.senvainc.com/catalog/doc...sitivities.pdf

If there is a flammable gas buildup, I still want to know about it. That's more of a feature, than a bug.

[team karst]

Still a mystery. Have had 8 hatches open for over a month now. No L/A charging for weeks. I blasted both suspect alarms with breathing quality air. Back in service.

Too bad the gas chromatograph was left behind. The job i left was designing parts of those.
Cross sensitivity was a spec we dealt with. Target gases included hydrogen, methane, heptane, ethane, and acetylene. Your basic explosive gas mix for transformer oil.

[teneicm]

We had the same issue with a couple of Kidde smoke detectors when we got deep into the tropics and the humidity levels soared. Intermittent going off, etc. Can't prove it was just the humidity, but it only seemed to affect the ones in the cabins with less air movement.

[Jackpmyers1948]

I had a failing house bank battery set off the CO detector. The battery was very hot and gave off an odor.

[Photonsailor]

In the early years of owning and refitting our previous sailboat, we had the smoke and gas alarm go off repeatedly moored in a marina. Sometimes but not always, after coming back to the boat after some hiking. Hatches closed, because you never know when the next shower is gonna hit in the Scandinavian summer.

So, sometimes it alarms, sometimes no alarm and none for our noses discernible smell, not even my wife's nose! I thought, very annoying this thingy, and I have to hinder wife using it as a frisbee. After a few days I realize it only goes off when we have the wind in from stern. I had also upgraded the propane locker to a for purpose built "airtight" gas bottle container, with drainage out at bottom through assigned throughhull, and air-inlet from top to outside. I also had electrical remote switch on the bottle, always off when not using stove (a must security feature I think).

So, I was in denial! There could not be any unwanted gases, right? Shame on me!

My annoyance threshold was finally reached, and I realized there must be something with the gas container set-up! Lo and behold, after following the out-drainage under a lot of stuff and under the floorboards to the through hull I see that the valve was in the CLOSED postion (do not ask me why)!!

So, the very tiny amount of gas diffusing out from the couplings on the gasbottle, had no way to go, and with wind in from stern into the air intake, it was enough pressure to force out a tiny amount of gas (bottle shut off by remote when not in use) and waft it forwards into the living quarters with air from the stern dorades (again, we did not smell anything)!

Since then, I NEVER ignore any gas alarms. Especially not if they would go off repeatedly! They might actually do their job and warn you correctly! We lived to learn!

[s/v Jedi]

Originally Posted by Photonsailor

In the early years of owning and refitting our previous sailboat, we had the smoke and gas alarm go off repeatedly moored in a marina. Sometimes but not always, after coming back to the boat after some hiking. Hatches closed, because you never know when the next shower is gonna hit in the Scandinavian summer.

So, sometimes it alarms, sometimes no alarm and none for our noses discernible smell, not even my wife's nose! I thought, very annoying this thingy, and I have to hinder wife using it as a frisbee. After a few days I realize it only goes off when we have the wind in from stern. I had also upgraded the propane locker to a for purpose built "airtight" gas bottle container, with drainage out at bottom through assigned throughhull, and air-inlet from top to outside. I also had electrical remote switch on the bottle, always off when not using stove (a must security feature I think).

So, I was in denial! There could not be any unwanted gases, right? Shame on me!

My annoyance threshold was finally reached, and I realized there must be something with the gas container set-up! Lo and behold, after following the out-drainage under a lot of stuff and under the floorboards to the through hull I see that the valve was in the CLOSED postion (do not ask me why)!!

So, the very tiny amount of gas diffusing out from the couplings on the gasbottle, had no way to go, and with wind in from stern into the air intake, it was enough pressure to force out a tiny amount of gas (bottle shut off by remote when not in use) and waft it forwards into the living quarters (again, we did not smell anything)!

Since then, I NEVER ignore any gas alarms. especially not if they would go off repeatedly! They might actually do their job and warn you correctly! We lived to learn!

Hear hear! I have always been saying that these are not false alarms and I’m usually ridiculed for it. But there’s something triggering the sensor so it’s not a false alarm. For new boats it’s out gassing from materials or even paint still curing etc.

[paul2884]

doesn’t help in this case as the OP has a fire alarm problem but domestic CO alarms are susceptible to damp and that’s why they sell different ones for boats.

[justlearnin]

Originally Posted by team karst

We have 5 CO/smoke detectors on board. All new in 2022. Two have gone off in smoke detect mode. Inconsolable, have permanent batteries. Put them in zip locks to shut them up.
Not cooking, nothing unusual going on. Genset, both engines off. Unit one was in a berth a couple weeks ago, this last one in the saloon.
Any history with these?

I dont know if they are the same as the KIDDE units in my home BUT my combos last just out the warrenty period and then start going crazy. I have hard wired my house 1 smoke in each bedrm, 1 in attached storage garage, 1 combo in the hall 1 combo in basement. (I also have a wired and battery smoke in the same rm in the basement because I dont trust these pos's.) At 60 bux when the combos go it is a pita. I have done away with battery types in the smokes. Only the combos have batts so when I shut the breaker they at least stop yelling. Ps I am a former Fire Alarm tech and know about smoke dets and these are crap. Like I said I dont trust them. Oh also a stand alone carbon in the hall by the bedrooms.

[sinnerman]

Joining he fray:

-Dust as mentioned
-Mold on the sensor (gee, mold on a boat?...LOL)
-Cooked electronics form being in a closed boat in the sun...

cheers

[thinwater]

Originally Posted by CaptTom

Live and learn! I knew about Hydrogen, I've watched it bubble out. So what is that "rotten egg" smell when a battery is overcharging? I just assumed that was what was causing the detector to alarm. Hydrogen rises in air. I know at least once I've heard the CO detector go off due to battery charging, when the detector wasn't on the overhead, or near or above the battery compartment, so it wouldn't have "seen" much Hydrogen.

The classic "rotten egg" smell is hydrogen sulfide (H2S), but a battery that is charging hard will emit H2SO4 (battery acid) fumes, which have a related smell.



H2 rises quickly, but in a closed cabin it does not really have a place to go. And like hot air, once it mixes in with the other air in the cabin, it does not separate, at all. That is myth. It only rises separately when there is no mixing, similar to how propane settles through air when undisturbed, but does not separate once mixed in. So the detector would NOT have to be over the battery. Another myth.

[thinwater]

Originally Posted by Photonsailor

In the early years of owning and refitting our previous sailboat, we had the smoke and gas alarm go off repeatedly moored in a marina. Sometimes but not always, after coming back to the boat after some hiking. Hatches closed, because you never know when the next shower is gonna hit in the Scandinavian summer.

So, sometimes it alarms, sometimes no alarm and none for our noses discernible smell, not even my wife's nose! I thought, very annoying this thingy, and I have to hinder wife using it as a frisbee. After a few days I realize it only goes off when we have the wind in from stern. I had also upgraded the propane locker to a for purpose built "airtight" gas bottle container, with drainage out at bottom through assigned throughhull, and air-inlet from top to outside. I also had electrical remote switch on the bottle, always off when not using stove (a must security feature I think).

So, I was in denial! There could not be any unwanted gases, right? Shame on me!

My annoyance threshold was finally reached, and I realized there must be something with the gas container set-up! Lo and behold, after following the out-drainage under a lot of stuff and under the floorboards to the through hull I see that the valve was in the CLOSED position (do not ask me why)!!

So, the very tiny amount of gas diffusing out from the couplings on the gas bottle, had no way to go, and with wind in from stern into the air intake, it was enough pressure to force out a tiny amount of gas (bottle shut off by remote when not in use) and waft it forwards into the living quarters with air from the stern dorades (again, we did not smell anything)!

Since then, I NEVER ignore any gas alarms. Especially not if they would go off repeatedly! They might actually do their job and warn you correctly! We lived to learn!

^^^ And this!

Normally a gas locker drain does not have a valve, since it must be above the waterline. And so you can't close it!!


With several boats and many years in industry, I've seen very, very few true false alarms. Virtually every time there was something. Not always what was on the label, but something worth correcting.