Unexplained CO alarm

PascalG

PascalG

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Confused. For the first time in maybe 20 years I have had a CO detector going of. Actually not just one but two an hour apart. At the dock on shorepower.

First one in the forward stateroom at around 2am and the second one an hour later in the master. Each time I got up, silenced it, went up on deck to see if anything outside could be a source like a guy with a gas boat nearby. My boat is diesel so CO issue are extremely rare, the only reason I really have CO detectors is in case we dock somewhere and a nearby gasser runs its mains or gen at the dock. Not the case here since everything around is diesel

So what could trigger two detectors, to go off for no reason? both are about 2 year old so fairly new.
 
We had this happen to us as well. We had two new detectors go off in the aft cabin. Both sounded off very close in time. We got up and looked around outside. We heard nothing and saw nothing unusual. We went back inside, left the windows open a while and it was a done deal. It was a chilly but very still evening so it could have been gas from some other area that wafted over us. There was frost on the deck. Who knows. The alarms never went off again. The only thing was this was after a long run down the icw that day taking us to a one night stop.
 
Make and model of the CO detectors? Are the detectors part of a proper fire/smoke/heat/CO alarm system or do you use stand alone consumer grade "Residential" style units. Are the CO detectors interconnected? You would rather have a false alarm than for the system to fail to alarm at all. Two units alarming doesn't sound like a false alarm. Any engine that consumes hydro carbon fuel creates CO. There are deaths, documented by the USCG, attributed to CO poisoning from diesel powered, portable pumps. The USCG issued a safety circular a few years back on the very issue. CO exposure is cumulative and a little bit goes a long way. You can purchase Single Gas portable detectors for about $100 that will alarm at a preset level. Several sources manufacture CO monitors to document the time, date and concentration of the CO level in a compartment or void space.
 
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Yes stand alone CO/Fire detectors, the same brand that have passed multiple surveys on various diesel boats I ve run.

Again, that was at my home dock on shorepower. No machinery running on my boat in the 24 hours prior and no boats running any engine at the time in any of the nearby slips. I went up deck each time to check

Yes diesel can produce some CO but incidents are very rare. I have never add a CO detector alarm because of diesel exhaust. And I ve had to run diesel gens at the dock many times during power outages.
 
Is the boat locked down for Summer with the A.C. running? Just curious if fresh air is getting into the boat or if it was closed up tight to stay cool.
 
Any chance you had a unusual humidity level event? Since it hit 2 detectors and never happened before or since that is the only random variable I can think of not already discussed.
 
Residential Smoke/CO alarms are not manufactured for use in the marine environment. If you contact any of the manufactures they will tell you "Residential Use Only".
 
I thought so but I ran this by two surveyors over the years, first on an 84 and then on a 116 they were surveying and they said they were fine. Whether marine or residential, I still don’t understand the alarm with no machinery running
 
Well, there is always the evermore present lack of quality control in manufacturing of a great many items now days. Built-in obsolescence is and always has been a valid consideration!
 
Yeah. But both within an hour… we have 10 of them in the “office” next slip, never had an issue. I even went and poke my head in, none were sounding. It was something inside my boat but I can’t figure out what.
 
Got any new pillows or upholstery aboard? Gas off of soft goods can often trip CO detectors
 
That was not the case with our incident. We were coming down the ICW and stopped for a night. Could be some weeped up into the aft cabin from the exhaust but still very eerie since the windows were closed due to it being a very cool evening that layed down a thick layer of frost on the decks.
 
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Another thought is propane. Do you have propane on board? If so you may have a leak. Yes, raw propane will set off CO detectors.
 
No propane on boat that size. All electric. I don’t even have an outside propane gri
 
PascalG said:
No propane on boat that size. All electric. I don’t even have an outside propane gri
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The only thing that will set them off is burned or unburned hydrocarbons. Anything from a pillow to a leaky tank.
 
Hmm. Diesels return quite a bit of fuel to the tanks. It is cooled on the return leg. At least it is on our old boat. Makes me wonder since the tank was in between the two alarms on our boat (queen aft).
 
I did an addition in my house 10yrs and maybe a few months ago. All of the installed smoke and combo smoke/CO detectors died within a few days. Of course when the first one went I tried a new 9v battery backup, no joy. Drove me nuts!

Turns out....these things have an END OF LIFE at 10 years and all died together...WTF! Total replacements needed. Get the model number and google to see if your CO detectors have this "feature"...drove me nuts!
 
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