Carbon dioxide monitor

I have a client who has CO2 monitors in his boat that are giving a warning signal. The doors and hatches were open for a day with fans and the air conditioning running.The engines and generator have not run for over two weeks, the batteries have been checked so that overcharging from a bad cell is not a likely cause, The power had been off for a week when Hurricane Irma passed by. A new monitor was purchased and that also is indicating an alarm.

Any suggestions?

First, we need to be clear. Are we talking carbon monoxide (CO) detectors, or carbon dioxide (CO2) detectors?
Since a new, replacement detector is still issuing a warning alarm, I would assume there is, somewhere on the boat, a source of CO that is leaking. Need to find it and fix it.
If you have not already done so, suggest running the bilge blowers to remove any residual gas from a prior incident, then see if you still get an alarm.

Could be a nearby boat or other source of CO. Are you using a marine grade detector? Home detectors and marine detectors have different alarm algorithms.

Any neighbors running a generator?

Dont think I ever had a CO detector do it, but have had smoke detectors chirp in real humid conditions.

Try a bit of hot air from a hair dryer......

Home detectors

hmason said:

Could be a nearby boat or other source of CO. Are you using a marine grade detector? Home detectors and marine detectors have different alarm algorithms.

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While cheaper home detectors are more sensitive, sometimes my home detector will pick up the CO from my weed eater or lawn mower running outside my home. I used a home detector in one of my boats and it was so sensitive backing out of my slip would set it off.

You can bet there is something in the air. Mine alarmed from a failed 1 year old AGM battery cell. It was the last place I thought would be the source

High Wire said:

You can bet there is something in the air. Mine alarmed from a failed 1 year old AGM battery cell. It was the last place I thought would be the source

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Yup, I have 3 CO monitors on my boat and one night while doing some (turned out to be excessive) battery charging, one went off. All 3 indicated CO detection levels on their numerical displays which are all normally at 0. If I hadn't previously read that battery outgassing could do it I probably wouldn't have known what to do.

I'm guessing a nearby boat running a generator or a battery problem.

Ken

yachtbrokerguy said:

I have a client who has CO2 monitors in his boat that are giving a warning signal. The doors and hatches were open for a day with fans and the air conditioning running.The engines and generator have not run for over two weeks, the batteries have been checked so that overcharging from a bad cell is not a likely cause, The power had been off for a week when Hurricane Irma passed by. A new monitor was purchased and that also is indicating an alarm.

Any suggestions?

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Carbon dioxide is what puts the fizz in your beer. Carbon monoxide is what makes you take a dirt nap.

That said, one of the most reliable tests of a carbon monoxide monitor is testing it against a new or "known good" detector. Apparently this has been done and the new detector is detecting carbon monoxide.

This is not good and you shouldn't stay in the area for very long.

You could start by ventilating the boat thoroughly. It's possible that you are picking up CO from a neighboring boat with an engine or genset running. I don't know if propane would set off the alarm but it's worth a shot.

It's possible that your local fire department has equipment to locate a CO source. It wouldn't hurt to call and ask.

My was going off a lot with no reason when I read the manual it was very clear only a few brands of batterys were to be used change to the right battery no more false alarms

Also, new carpets, plastics and chemicals such as in paint can set them off too. Been using solvents? Repaired some fibreglass? New bedding compounds? New bedding?!

One thing that needs to be tested is voltage drop to the detector. ABYC standards require detectors to sound off if they fail. Low voltage would cause them to sound off. It’s any easy test and might eliminate a lot of head scratching.

Are these wired into the ships batteries or are they powered by replaceable batteries? If replaceable, did the new unit get a new set of batteries, too?

I tried several Home Depot CO detectors and they were always going off. Finally I coughed up the hundred or so bucks and got a marine CO detector which solved the problem.

Cross contamination is common. As mentioned failed batteries on charge, solvents new paint or upholstery gassing off. Add cleaning products to the list. A boat I was looking after had a sensor go into alarm due to a drier sheet put near it to mask odours. I don't recall if it was smoke, gas or CO but it ruined the sensor due to the cross contamination. Drier sheet wasn't on it, just near it. Drier sheets are often used as an air freshener on stale smelling boats.
These things don't necessarily produce CO but something else that the sensor will detect and could damage it like in my example.
My first guess? After all the venting you did, bad batteries in the detector. New batteries and it still alarms after all that venting, use a meter and check your new batteries.

BTW. CO kills and maims. If you look up safe levels for the workplace, they don't apply to a home or boat because the workplace exposure is for a maximum of 8 to 12 hours and then the person is off the worksite and their body is flushing out the contaminant. At home or on the boat you might be exposed around the clock for days with no chance for your body to purge the toxin. Allowable exposure levels will be much lower for living areas.

yachtbrokerguy said:

I have a client who has CO2 monitors in his boat that are giving a warning signal. The doors and hatches were open for a day with fans and the air conditioning running.The engines and generator have not run for over two weeks, the batteries have been checked so that overcharging from a bad cell is not a likely cause, The power had been off for a week when Hurricane Irma passed by. A new monitor was purchased and that also is indicating an alarm.

Any suggestions?

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In my experience, in almost every one of these mystery alarm cases it's turned out to be an over-charging (the result of a defective charger) or shorted battery releasing excessive amounts of hydrogen, and hydrogen sulfide (associated with the rotten egg odor) gas, which will set of a CO detector. I'd take a close look at all batteries, look for case distortion, over heating or low electrolyte for the flooded variety.

Steve DAntonio said:

In my experience, in almost every one of these mystery alarm cases it's turned out to be an over-charging (the result of a defective charger) or shorted battery releasing excessive amounts of hydrogen, and hydrogen sulfide (associated with the rotten egg odor) gas, which will set of a CO detector. I'd take a close look at all batteries, look for case distortion, over heating or low electrolyte for the flooded variety.

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And of course, you can disconnect the charger, ventilate the boat and see if that stops the alarming. If it does, reconnect the charger and see if the problem returns. Then you'll know for sure.

Happens to me when doing a equalization charge on the battery bank.

What Steve D said - every time in my experience. Unless - there's a proximate source from say, another boat or lawn mowers, etc. nearby.