CO monitors sounding

[billdomb]

Some weird stuff with our CO monitors going off recently.

We'd put a blower into our lazarette where our gennies sit, and all of a sudden started having the CO monitor start blaring in the master's cabin sitting just forward.

Then another one in the engine room further forward started to sound off.

We turned up the ventilation in the spaces, and the alerts went away.

But now the engine room monitor has gone off again but the gennie's NOT running. Went up to 88PPM. NO other potential CO generators aboard, far as we know.

We tested with a hydrogen source to see if battery off-gas might be a culprit, but the monitors didn't respond.

Again, venting the compartment stopped the issue and it hasn't come back for over a day. And this time, the gennie's been running.

And, no, all monitors have new batteries or are connected to electrical outlets.

VERY puzzling and disconcerting.

[john61ct]

Is it only a CO detector, or also hydrocarbons?

[Spot]

How old are the monitors?

I had one go off at the house. The local Fire Department came in with a CO 'sniffer' and tested the gas stove, furnace, and water heater. None of those were the culprit. They chalked it up to the age (7 years) of the monitor and told me to replace it. I got a new one and no more alarms.

I had also done some painting with an alcohol-based primer a week previous, which stunk up the whole house. I also wondered if that was part of the failure mode, helping to push the monitor to expiration.

[boatpoker]

Cut'n'paste .......

How Often Should I Replace my Carbon Monoxide Detectors?
The conventional wisdom on this is to replace the detectors once every five to seven years, but there’s a little more to it than that. Consumer Reports offers a helpful guide that points out that these detectors will start emitting a chirping sound at the end of their useful life that’s different than the chirping sound that means “change my battery.” So most of the time, you only need to replace them when you hear the chirp. They also point out that newer, digital models usually have a digital display of some kind and can tell you if they are malfunctioning.

The good news is these things are designed to self-monitor and let you know if they detect a problem within. But just in case, you should also check the battery twice a year and test it regularly using the test/reset button. This will ensure the device is working properly when you need it most.

[billdomb]

Originally Posted by john61ct

Is it only a CO detector, or also hydrocarbons?

Sold as CO monitors and don't MENTION anything about hydrocarbons.

[billdomb]

Originally Posted by Spot

How old are the monitors?

I had one go off at the house. The local Fire Department came in with a CO 'sniffer' and tested the gas stove, furnace, and water heater. None of those were the culprit. They chalked it up to the age (7 years) of the monitor and told me to replace it. I got a new one and no more alarms.
.

Some old, some brand new. New ones are not going off, so maybe it's just age catching up.

[john61ct]

Yes, need replacing every 5 years

[Bean Counter]

Check this link, may have been your stove?
https://www.boatus.com/magazine/2016...-your-boat.asp

[Singularity]

Originally Posted by billdomb

Some weird stuff with our CO monitors going off recently.

We'd put a blower into our lazarette where our gennies sit, and all of a sudden started having the CO monitor start blaring

You have a serious problem on your hands not related to malfunctioning sensors. If I'm wrong I'll gladly eat my hat and roll in the end result with pictures if you like. Please do not listen to people who give you advice to replace your sensors to "see what will happen."

You made a change that produced a result of two different alarms screaming. To suggest that two separate sensors just decided to "expire" concurrent with the ventilation change is sort of ludicrous and about as inconsiderate of advice to give under the circumstances as possible.

On my boat...if I pumped it full of carbon monoxide...I can imagine so many pockets of air here/there (aptly named dead space) that could contain CO to keep the CO sensors going off for a while. You need to understand that carbon monoxide...any amount...steals oxygen from your tissues.

I would highly recommend, if possible, turning off all electricals (disconnecting all power sources), turn off all fuel selectors, certainly don't run anything. Open all vents, electric blowers (connected to shore electricity not through the boat) for a day or so. As previously mentioned, call the fire department to come out with a CO sniffer.

If a CO sniffer is not available...after airing out the boat for a day or so, with the alarms not going off but operating, go back down and inspect the living sh!t out of all your systems.

Don't stop when you find the problem (unless clearly a gaping hole/crack situation). Inspect everything. In radiology there is a problem often called the "happy eye syndrome" (an observation bias) that occurs when the radiologist finds a big ~thingy that was not the actual problem and stops looking further. The thingy gets treatment (often unnecessary in the first place) while the real bad guy is still free to cause problems. This is why one must be comprehensive (at least when the result of missing the problem can cause serious injury or worse).