CO detectors - chirp chirp chirp!!

[billgewater]

Originally Posted by garychurch

My hard wired CO detectors did the same thing, all of them almost in unison. Found out the radium in these were depleted after 5 years. Bought new ones with a 7 year radium lifespan.

The radioactive isotope of radium isotope 228 is 5.75 years (the other isotopes have longer half lives) which may explain the short effective life of the detectors. But I had always thought that CO detectors relied on the transparency of a small silica gel blob that due to various additives changed transparency due to the reducing ability of CO. It causes chemical changes that changes the transparency, so I am not sure just why radium would be used. Light would be OK. Does your CO detectors have those small radioactive warning stickers?
Radium 226 has a half life of 1600 years but the others (not 228) have a half life measured in weeks.
Although half life is certainly not an indicator of effective life use in a particular application, I would be very suspicious of a CO detector that had a radioactive sticker and claimed a 7 year life time.
If there is no radiation sticker then it probably does not use radium at all but may rely on opacity or electrical impedance changes. Maybe someone can enlighten us further.

[01kiwijohn]

Originally Posted by Rohan

My boat has 3 CO detectors that came factory delivered in 2006. One of them starts chirping every day. I press the reset button, and it is fine until the next day. I know it's not a CO problem because I haven't even been running the engine. No one around me has either, nor has anyone been running generators or anything like that. I come back to my boat at the marina the next day and it's going off again. Of course, the first thought is that the battery is low but these don't use their own batteries. They are hard wired into the boat and there is no switch that controls them, and no way to turn them off other than disconnecting the main battery bank. And my 12 volt batteries are fine, I checked them. In fact, I recently replaced half of them.

This is just annoying, but the other day another detector was in alarm mode when I arrived. It wouldn't stop alarming no matter what I did, so finally had to resort to cutting the wire, then re-joining it. And it was back to normal. They are Costar model detectors exactly like this: https://www.jmac.com/Quantum_Group_1...-12-24SIR.htm=

I have opened them up, cleaned out any dust, but still the problem persists. I could buy separate battery powered ones and use those instead but since the internal wiring already exists, I would rather use what I have.

Any suggestions? And do CO detectors normally lose their ability over time?

First thing to check, do you have the required voltage at the input to the detector? If below threshold it will do as you describe.

[Grattaway]

lots of detectors do have a life of circa 10 years and yes the chirping is a warning sign that the detector is now failing - so time for a replacement.
And get a new one with a test mode on it

[garychurch]

Here is some additional information on the new CO sensors that replaced the ones that quit after 5 years.


The Fireboy-Xintex CMD5-M CO alarm uses a sensor operating with a microprocessor to measure Carbon Monoxide (CO) levels. Using a “Time Weighted Average” (TWA) process, it monitors CO concentration, temperature and time to calculate levels of Carboxyhemoglobin (COHb). COHb is the degree to which the oxygen-carrying capacity of the blood is impeded by the union of carbon monoxide to the hemoglobin and is expressed as a percentage. The human body absorbs CO easier than oxygen and COHb is the ratio of absorbed carbon monoxide to oxygen in the bloodstream. The CMD5-M alarm calculates this COHb as a function of time and determines the appropriate alarm response.

You can link up to six CMD5-M detectors in multiple locations on your boat. This advanced CO alarm will alert boat inhabitants of the presence of CO. Drawing the lowest current of any Fireboy-Xintex CO detectors, the CMD5-M operates on either 12 or 24 VDC. An advanced design leaves the sensor unaffected by common cleaning solvents so you can keep your boat and CO alarm in tip-top shape. You can equip the CMD5-M with an optional RCM-5 relay (sold separately) so that when dangerous carbon monoxide levels are detected, it will shut down your boat’s generator.

Key Features

Electrochemical sensor
Immediate and stable sensing reduces false alarms
Ultra-low current draw, less than 4 mA.
Long sensor life
7 year End of Life (EOL)
Conformal coated circuit board for added protection
Microprocessor controlled
Relay module available for generator shut down
12/24 VDC current draw.

[Cpt Pat]

Originally Posted by a64pilot

How do you monitor it, which monitor and curiously, why? Assuming your correct you really ought to ventilate your sleeping compt, that’s about five times what outdoor air should be, and OSHA has set a max of 5,000 PPM for an eight hour work day.

I am using this monitor: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

The only difference between the CO2 levels in my cabin and the cabins of other boats is: I have a monitor to measure it.

Anything under 3,000 PPM is OK. Not wonderful, but acceptable. Higher CO2 levels can cause subtle "cognitive effects" (make you stupid) which is why there's some public discussion of CO2 levels in classrooms. Cheap schools with poor ventilation and air exchange. As if our public schools didn't have enough challenges already.

To answer some posts above: My CO monitors were Fireboy-Xintex Model CMD5-MD-R with factory date stamps less than 3 months old. THEY WERE NOT OLD. Two (both) failed by producing false alarms in the middle of the night. The units were provided different power sources by being connected directly to my boat's battery terminals, provided a supply voltage of 13.4 volts, and were connected to two different battery buses.

I am fully aware that CO and CO2 are different gases. The first deadly, the second naturally occurring. CO2 is a byproduct of the metabolism of glucose and only high levels are dangerous. If I didn't exhale CO2 - I'd be dead.

The connection between false alarms and elevated CO2 levels is only a hypothesis Something's wrong with them, and I'm proposing one possible cause. I am still waiting for FireBoy-Xintex to respond after I returned both CO2 alarms to them under RMA. If they ever respond with a definitive answer (not just head scratching) and have another explanation, I'll report it here.

[Cpt Pat]

Originally Posted by garychurch

Here is some additional information on the new CO sensors that replaced the ones that quit after 5 years.


The Fireboy-Xintex CMD5-M CO alarm uses a sensor operating with a microprocessor to measure Carbon Monoxide (CO) levels. Using a “Time Weighted Average” (TWA) process, it monitors CO concentration, temperature and time to calculate levels of Carboxyhemoglobin (COHb). COHb is the degree to which the oxygen-carrying capacity of the blood is impeded by the union of carbon monoxide to the hemoglobin and is expressed as a percentage. The human body absorbs CO easier than oxygen and COHb is the ratio of absorbed carbon monoxide to oxygen in the bloodstream. The CMD5-M alarm calculates this COHb as a function of time and determines the appropriate alarm response.

You can link up to six CMD5-M detectors in multiple locations on your boat. This advanced CO alarm will alert boat inhabitants of the presence of CO. Drawing the lowest current of any Fireboy-Xintex CO detectors, the CMD5-M operates on either 12 or 24 VDC. An advanced design leaves the sensor unaffected by common cleaning solvents so you can keep your boat and CO alarm in tip-top shape. You can equip the CMD5-M with an optional RCM-5 relay (sold separately) so that when dangerous carbon monoxide levels are detected, it will shut down your boat’s generator.

Key Features

Electrochemical sensor
Immediate and stable sensing reduces false alarms
Ultra-low current draw, less than 4 mA.
Long sensor life
7 year End of Life (EOL)
Conformal coated circuit board for added protection
Microprocessor controlled
Relay module available for generator shut down
12/24 VDC current draw.

Yes. That is the same make and model of alarm that failed for me. See post above.