Carbon Monoxide / Propane Tank Mystery

[huruta]

Hi. We have a mystery we are trying to solve. Last month we were in Hawaii when a cold snap occurred (low ~26F). When we got home and checked on the boat, the carbon monoxide alarm in the v-berth was going off and when we turned on the DC panel, the LPG alarm started sounding. The carbmon monoxide detector in the salon was not going off - we checked the batteries and it was working.

Since that we time we haven't had either alarm go off again, but carbon monoxide isn't something to mess around with and because the LPG alam was going off, we suspect this somehow is related to the propane tank for cooking. At the time we had two Airydryers on and nothing else and the boat hadn't been started in a few weeks (Hawaii was lovely!).

Our next step is to check the line between the solenoid to the range by turning on stove and then turning off range and propane tank and seeing if the pressure goes down. But we want to understand the source of the problem. We are struggling to figure out how a propane leak (if we have one) would lead to a carbon monoxide alarm going off - doesn't propane need combustion to generate carbon monoxide? Ideas, thoughts appreciated.

 

[kchace]

2 items come to mind. A carbon monoxide alarm can be set off by lead acid batteries that are being overcharged or have some other issue. The other is it’s possible the alarms were going off because of the cold temps.

Ken

 

[huruta]

2 items come to mind. A carbon monoxide alarm can be set off by lead acid batteries that are being overcharged or have some other issue. The other is it’s possible the alarms were going off because of the cold temps.

Ken

Thanks, Ken. Do cold temps set of carbon monoxide alarms? Is this a known thing? It seems improbable that both alarms would be unrelated (e.g. lead acid batteries) and go off simultaneously. Of course the improbable is not the impossible.

 

[Bacchus]

Sensors / alarms do age out / expire. Had 2 CO alarms age out a few mos apart and had to replace them. They should have an expiration date but may be hidden and need to remove to find them.

 

[Bmarler]

Thanks, Ken. Do cold temps set of carbon monoxide alarms? Is this a known thing? It seems improbable that both alarms would be unrelated (e.g. lead acid batteries) and go off simultaneously. Of course the improbable is not the impossible.

Ken is right. I’ve had my batteries set off both the co and propane alarms. I had a genset battery that had failed and was making the charger work hard and as a result, the house and main starter banks were off gassing. Got rid of the bad battery, all was well. Isolate your batteries and do a voltage check on them. You might find a bad cell.

 

[huruta]

Isolate your batteries and do a voltage check on them. You might find a bad cell.

Okay! How does one do this? Any how-to resources appreciated.

 

[kchace]

Thanks, Ken. Do cold temps set of carbon monoxide alarms? Is this a known thing? It seems improbable that both alarms would be unrelated (e.g. lead acid batteries) and go off simultaneously. Of course the improbable is not the impossible.

I can't say if the cold temps caused any of the alarms, but it is possible so I wanted to mention it.

 

[Bmarler]

Okay! How does one do this? Any how-to resources appreciated.

If you have a volt meter it’s easy. Just turn off the battery switches, then remove all the battery jumpers. Each battery should be isolated (unhooked)and let sit for 24 hours before measuring voltage. A fully charged lead acid battery should be resting around 12.7 volts.
Be sure to make a map of all the cables before you start unhooking them. Pictures are also a good idea.

 

[huruta]

Thanks, kchace...if we rule out propane leak and batteries are in good condition, the cold weather seems like a high potential culprit. Also, it's been a similar temp the last few days as when we were in Hawaii and so will check it now and see if it repeats itself now that I'm back from a work trip.

 

[huruta]

If you have a volt meter it’s easy. Just turn off the battery switches, then remove all the battery jumpers. Each battery should be isolated (unhooked)and let sit for 24 hours before measuring voltage. A fully charged lead acid battery should be resting around 12.7 volts.
Be sure to make a map of all the cables before you start unhooking them. Pictures are also a good idea.

I saw a youtube video that also mentioned a load tester in addition to using the multimeter. Would this be useful in this case?

Okay. I'm so not mechanical, but knew this going in when we bought the boat and I am liking the tactile learning challenges presented by boat ownership. Will take pics, create a map, and try and figure out what 'unhooking' means...should I be embarrassed by that last piece (unhooking)? Probably.

Good think my husband will undoubtedly know what you mean by this.

 

[Marco Flamingo]

I've have had a CO detector go off twice after cold snaps (down into the 20's). My batteries are in the aft lazarette, sealed off from the main cabin, bilge, etc. The CO detector that went off is in the forward berth. After checking everything several times, I concluded that it was the cold. The instructions for CO detectors warns against using in kitchens, laundry rooms, bathrooms, etc., where there might be high humidity. That could happen on a boat where the temperature drops to the dew point. You would not be able to see any "fog," but the detector might see microscopic water particulates in the air.

 

[Bmarler]

I saw a youtube video that also mentioned a load tester in addition to using the multimeter. Would this be useful in this case?

Okay. I'm so not mechanical, but knew this going in when we bought the boat and I am liking the tactile learning challenges presented by boat ownership. Will take pics, create a map, and try and figure out what 'unhooking' means...should I be embarrassed by that last piece (unhooking)? Probably.

Good think my husband will undoubtedly know what you mean by this.

Just checking the resting voltage should be good enough. Unhooking is simply removing any cables attached to the battery so that it’s disconnected from the boats wiring.
If you want to load test, a better way is to apply a known fixed load for a time period and see if they deliver as expected. Let’s not go there just yet.

 

[kchace]

I saw a youtube video that also mentioned a load tester in addition to using the multimeter. Would this be useful in this case?

Okay. I'm so not mechanical, but knew this going in when we bought the boat and I am liking the tactile learning challenges presented by boat ownership. Will take pics, create a map, and try and figure out what 'unhooking' means...should I be embarrassed by that last piece (unhooking)? Probably.

Good think my husband will undoubtedly know what you mean by this.

Be a bit careful with Youtube, There's a lot of good info there but also a lot of poor mixed in. A load test is not very useful on a house bank which is what I assume (and hope) is what is running your house loads. A load test is helpful on a starting battery, but is still a pretty coarse test. Since start batteries are so critical, IMO if one even suspects a start battery may be near the end of its life, it should just be changed.

Ken

 

[huruta]

bmarler and Ken, Thanks for the guidance. We haven't had any trouble with the batteries but a simple resting voltage check makes a lot of sense in terms of where to start. Regardless, I've meaning to check if they need water and a voltage check seems like a good skill to have. Will report back.