Carbon Monoxide Alarm going off...worrying!

[mattnj]

last week the CO alarm went off on 2 seperate occasions, 3 nights apart, both were at almost exactly the same time, within a few minutes of midnight....

There was nothing on, or running (gas, engine, heaters etc) and there handn't been for at least say 6+ hours beforehand, the only thing is that both nights it was on shore power and the batteries would have been on charge, When it happened I opened all the windows for 5 mins, pressed the reset button and went back to sleep, it happened again about 3 nights later when on shorepower again, I opened the windows (and left them open) pressed reset and went back to sleep....

Any ideas, I am pretty sure that battery charging doesnt give out CO, but maybe it does give off something that may set off a CO alarm, or is the CO monitor faulty, any other ideas?

Never had this before....

 

[RAI]

Alarm Batteries

How old are the CO alarm's batteries? Some give a squeak as their last attempt to warn of dead batteries.

 

[Seajet]

Battery charging gives off hydrogen; don't know if that or any other by-product may upset the alarm.

Seems unlikely given the time of night, but there wasn't an engine running just upwind by any chance ?

 

[alant]

last week the CO alarm went off on 2 seperate occasions, 3 nights apart, both were at almost exactly the same time, within a few minutes of midnight....

There was nothing on, or running (gas, engine, heaters etc) and there handn't been for at least say 6+ hours beforehand, the only thing is that both nights it was on shore power and the batteries would have been on charge, When it happened I opened all the windows for 5 mins, pressed the reset button and went back to sleep, it happened again about 3 nights later when on shorepower again, I opened the windows (and left them open) pressed reset and went back to sleep....

Any ideas, I am pretty sure that battery charging doesnt give out CO, but maybe it does give off something that may set off a CO alarm, or is the CO monitor faulty, any other ideas?

Never had this before....

Farting?

 

[planteater]

Some of the CO alarms also detect narcotic gas. Is somebody trying to poison you?

 

[mattnj]

Battery charging gives off hydrogen; don't know if that or any other by-product may upset the alarm.

Seems unlikely given the time of night, but there wasn't an engine running just upwind by any chance ?

no, it was dead still nothing going on. I have never had it before, so maybe its just a sign the batteries have had enough? Do they gass more when old?

When the alarm was going off, the monitor was showing 14.7v and charge of 1.5amps (220ah bank), it had been like that since about 18:00

Is that the problem?

 

[mattnj]

Some of the CO alarms also detect narcotic gas. Is somebody trying to poison you?

could be, but there would be easier ways!

Strange that in a week it only happened when on shore power and at night when all the hatches where shut, has to be the batteries?? Question is, is it something to worry about!

 

[snowleopard]

I had CO alarms that went off as a result of electrical interference from my SSB.

 

[Robin]

14.7V charge is high and would cause the batteries to give off gas. Maybe your CO also reacts to Hydrogen?

 

[Grajan]

I read a very similar story recently where it was the owners mobile phone that was setting the alarm off.

 

[Seajet]

One thing, if it is hydrogen, I'd strongly suggest some better vents near the batteries; does the name 'Hindenburg' ring any bells ?

Plenty of boats - and people - have been taken out by this, usually a very big bang rather than 'just' a fire...

 

[Bodach na mara]

How old is the alarm? The sensors on these things seem to have a limited lifetime. We are on our second one at home. The first lasted a week and was replaced by B&Q. The second lasted for 3 years then started giving erratic readings then sounded off when there were no appliances on. It is turned off just now, but I will need to renew it before our annual gas inspection as it was one of the recommendations.

 

[VicS]

I don't know but it would not surprise me if the metal oxide type of CO detector was sensitive to hydrogen!

They are based on detecting a small temperature rise when CO reduces the heated metal oxide. Other gases, such as hydrogen, which could reduce the metal oxide may well give a response.
It is not inconceivable that methane in so called "fart gas" would cause a response!

 

[huldah]

Carbon Monoxide Alarm.

I too, have had problems when the sensors age. Mine had exceeded it's recommended life.

 

[VicS]

I too, have had problems when the sensors age. Mine had exceeded it's recommended life.

What type of sensor?

 

[BSSOffice]

CO alarm sensors are sensitive to and can be triggered by hydrogen from gassing off batteries according to our contacts at CoGDEM, the trade body for the CO alarm manufacturers.

While the hydrogen being detected may not necessarily be within the flammable limits, it may be prudent to consider what the path of the gas is and whether there are potential ignition points - including static sparks. Most years we have a few reports of battery explosions, some from ignition of vapours while batteries are charging.

Hydrogen rises and on reaching the outside space will readily dissipate. Where there are concerns about the potential for explosion, consider either moving the batteries to somewhere where venting will be directly to fresh air with ignition risk reduced, or consider the use of trunking or 'channelling' gassed off vapours to fresh air.

If you think the hydrogen isn't a problem, you may wish to move the alarm to avoid non-CO activations.


HTH

 

[VicS]

CO alarm sensors are sensitive to and can be triggered by hydrogen from gassing off batteries according to our contacts at CoGDEM, the trade body for the CO alarm manufacturers.

But only the metal oxide types. ??

Have you asked them about methane?