Dehumidifier sets off Carbon Monoxide Detector, why?

So a few months ago, I installed 6 networked smoke detectors, one with a CO (carbon monoxide) detector. I've had 3 alarms from the CO detector, all when my room dehumidifier was running on the boat? The dehumidifier is the type that has a built in compressor and maintains a set humidity level in the boat. It sits on the counter next to the sink where it drains to, and is about 8 to 10' from the smoke detector. After the 3rd alarm, I flushed the detector in fresh air for an hour and stored it in a ziplock bag. Reinstalled the detector for my trip North. 3 weeks without a peep.

There's nothing wrong with the dehumidifier. Why does it trigger the CO detector?

Ted

My mystery CO detector sounding was using the AC. It circulated battery fumes from an 8D going bad and tripped the CO alarm. Maybe check your batteries just to be sure?

Good luck Ted!

John

Capt Jack said:

My mystery CO detector sounding was using the AC. It circulated battery fumes from an 8D going bad and tripped the CO alarm. Maybe check your batteries just to be sure?

Good luck Ted!

John

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Batteries aren't the problem. Dehumidifier sits on the counter, so no way to get vapor from the engine room.

Ted

O C, my best guess (after 1 adult beverage) is the dehum is generating/exhausting ions that trip the CO detector.

CO by itself has a lot of polarity and wants to bind with other stuff, that's what makes it a hazard to our red cells. The possible ions that come to mind would be polarized H2O, nitrogen (NOx) compounds, or maybe even CO2 that lost an oxygen (that is a long shot, takes a lot of energy.) Fan blade tip energy can generate ions, as well as other energy phase equipment in the process stream. A fan motor with commutator/brushes cranks out ions all day.

I've had positive and negative experiences with ions across several engineering projects (bad engineer joke).

So, I think, how would a Mexican fix it? (I live in baja 4 mos/yr.) Maybe try metal screen over the exhaust that is well-grounded, to grab whatever mysterious ions are blowing out. Cheap to try. Point the exhaust away from the detectors, gives the air stream time to discharge on other surfaces.

Email the CO detector guys and maybe the dehum guys too.

Interesting (and annoying) problem.

GoneFarrell said:

O C, my best guess (after 1 adult beverage) is the dehum is generating/exhausting ions that trip the CO detector.

CO by itself has a lot of polarity and wants to bind with other stuff, that's what makes it a hazard to our red cells. The possible ions that come to mind would be polarized H2O, nitrogen (NOx) compounds, or maybe even CO2 that lost an oxygen (that is a long shot, takes a lot of energy.) Fan blade tip energy can generate ions, as well as other energy phase equipment in the process stream. A fan motor with commutator/brushes cranks out ions all day.

I've had positive and negative experiences with ions across several engineering projects (bad engineer joke).

So, I think, how would a Mexican fix it? (I live in baja 4 mos/yr.) Maybe try metal screen over the exhaust that is well-grounded, to grab whatever mysterious ions are blowing out. Cheap to try. Point the exhaust away from the detectors, gives the air stream time to discharge on other surfaces.

Email the CO detector guys and maybe the dehum guys too.

Interesting (and annoying) problem.

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Ok, that's interesting. Dehumidifier discharge is pointing away from the detector. The fan is unusual in that the blades are attached to an outer ring as in the picture, but the blades are straight, not curved.



Ted

My Frigidaire dehumidifier kept tripping out the Magnum 2812 inverter/charger when plugged into shore power. New and different brand dehumidifier solved issue. I was totally flummoxed as to what was tripping the Magnum, a very smart tech set me straight.

The old unit is now working fine in a garage keeping an old Caddy dry in the BC humidity. But Ted, I agree

O C, that looks to be a relatively quiet fan. The outer ring kills the vortex shedding off the tips. Curved blades are usually quieter. And I am betting that is a brushless motor turning it.

Do you know what kind of CO detectors you have? Electrolytic or ?

GoneFarrell said:

O C, that looks to be a relatively quiet fan. The outer ring kills the vortex shedding off the tips. Curved blades are usually quieter. And I am betting that is a brushless motor turning it.

Do you know what kind of CO detectors you have? Electrolytic or ?

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Yes, very happy with the dehumidifier. It's quieter than previous units I've had.

CO detector is Electrochemical.

Ted

sunchaser said:

My Frigidaire dehumidifier kept tripping out the Magnum 2812 inverter/charger when plugged into shore power. New and different brand dehumidifier solved issue. I was totally flummoxed as to what was tripping the Magnum, a very smart tech set me straight.

The old unit is now working fine in a garage keeping an old Caddy dry in the BC humidity. But Ted, I agree

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Really liked my Frigidaire dehumidifier until something rusted through (rust in condensate) in the freon loop and lost the dehumidification. No worries, they replaced it under the one year warranty. That one did the same thing a year later. No warranty on replacement units. I moved on.

Ted

Ted

There's a thought, freon leak again albeit in a different unit. Or furniture polish, incense, mosquito repellent etc which can trigger some alarms.

sunchaser said:

Ted

There's a thought, freon leak again albeit in a different unit. Or furniture polish, incense, mosquito repellent etc which can trigger some alarms.

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Think it still comes back to the dehumidifier. If it's a freon leak, it must be really slow as the dehumidifier still works great. I was 22 days onboard without it going off once. Only thing that I can see as different was no dehumidifier. I ran hot water heat off the engine, heat through the AC units, air conditioned with shore power and the generator, cooked, windows open and closed while underway and not a peep from the CO detector. Never used furniture polish, incense, mosquito repellent or really anything else that went into the air.

Ted

Was the dehumidifier new? If so, perhaps it would outgas manufacturing solvents, sealants, plasticizers, etc. for awhile.

Given all the problems I've had with 13 networked Co2 detectors in my house, there is no way I'd have even one in the boat. Although I do have one. And it malfunctioned and sounded continuously until the fuse was pulled. These things don't work flawlessly.

Unit is 6 to 7 months old. CO detector is about 2 to 3 months old.

Ted

Ted- Just read your post and was curious if you solved the problem. Also was wondering, are the CO detectors a standard home variety or marine rated?

cks said:

Ted- Just read your post and was curious if you solved the problem. Also was wondering, are the CO detectors a standard home variety or marine rated?

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The ones I have are Kiddee regular home models. The dehumidifier I switched to after the Frigidaire also developed a freon leak that was triggering the CO detector. After removing the dehumidifier, the detector kept developing false alarms and eventually wouldn't reset when taken outdoors in a rural area. I contacted the manufacturer about it not resetting. They offered to replace it no charge. Instead, I asked and they agreed to replace the unit with a smoke detector that would network with my other units. Have had zero problems since.

I decided that I could live without a CO detector as the engine and generator are diesel and not gasoline. I may revisit it at a later date, but it seems there are too many things on a boat that can trigger a CO detector without being CO.

Ted

Ted- I strongly recommend purchasing a marine rated CO detector. I have Fireboy units. They are about $100 each.
I am planning to add 2 more in parallel. One in the engine room and one in the salon.
I would like to run our Generator overnight and need this extra level of protection before feeling comfortable that I’ll wake up in the morning. ��

cks said:

Ted- I strongly recommend purchasing a marine rated CO detector. I have Fireboy units. They are about $100 each.
I am planning to add 2 more in parallel. One in the engine room and one in the salon.
I would like to run our Generator overnight and need this extra level of protection before feeling comfortable that I’ll wake up in the morning. ��

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I appreciate your concern. I don't think I've ever run my generator or engine when I was sleeping. Also, diesel engines produce far less CO than the equivalent gas engine.

Ted

I have a CO detector in our boat cabin. Just a cheapo Home Depot unit, can't remember the brand. Two AA batts. It has never gone off randomly, other than when batts get low and when detector ages out. Replaced unit once over a ten year period. Detector apparently has a finite life and will do short beeps to inform you. Just recently got some short beeps so it needs attention again.

I too run a dehum in the cabin and it has never set the CO monitor off. But I know batts charging or discharging can set them off (H2 I guess). Maybe other boat stuff. Ours has not annoyed us with bogus alarms.

I know diesel makes little CO, but it does make some. We take turns napping while the other is at the helm, and sometimes sleep on the hook with gennie running. It makes me more relaxed knowing we have a functional CO monitor.

cks said:

Ted- I strongly recommend purchasing a marine rated CO detector. I have Fireboy units. They are about $100 each.
I am planning to add 2 more in parallel. One in the engine room and one in the salon.
I would like to run our Generator overnight and need this extra level of protection before feeling comfortable that I’ll wake up in the morning. ��

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Do you have any definitive evidence or proof that a marine rated CO detector is better than a battery operated home style?


I am all behind having one or the other...just not convinced the marine ones are any safer...different maybe, but safer no.


I would rather have people buy somethng if they feel it's necessary than be timid because the marine rated ones have limitations such as requiring hard wiring.

I alway purchase marine rated products. Yes they are more expensive but are manufactured to a different specification standard. Marine electronics Components are conformal coated to reduce corrosion.

I use Xintex, Fireboy CO detectors in our boat. Here’s a brief description of operation vs. off the shelf home units.

The detector uses a microprocessor to measure and accumulate CO levels. Using the principle of “time-weighted averaging” (TWA), the CO Alarm monitors CO concentrations, 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. In layman’s terms, our bodies prefer absorbing CO to oxygen and COHb is the ratio of absorbed carbon monoxide to oxygen in the bloodstream. The CO Alarm calculates this COHb level as a function of time and determines the appropriate alarm time. SEE TABLE 2.
Should a very high level of carbon monoxide exist, the CO Alarm will alarm in a few minutes. However, if small quantities of CO are present or high levels are short-lived, the micro controller will accumulate the information and determine when an alarm level has been reached. This feature eliminates nuisance alarms. For example, in a boat it is possible to see high levels of CO for a very short time such as when docking or maneuvering. The CO Alarm takes this all under consideration by totaling the quantity of CO detected over a period of time.

Nice list of specs and theory...but are the specs designed to be all that practical and necessary?


Can those same conditions not exist in dwellings thus making the marine detectors that much more vessel specific and the home ones dangerous on a boat?


My detectors last in the marine environment just fine for the lifespan of the detector.


OK...I can go along that marine detectors are incrementally better...maybe....but for the price and inconvenience of wiring them up and false alarms I have encountered with them and the bad ones right out of the box (working for a boat dealer).... no thanks...I am good with home style ones.

Most of the modern home detectors also do that time averaging

For whatever it's worth, new to me boat and I'm having the same issue. No CO problem until I put a brand new dehumidifier in. Reading 35 ppm CO with no potential source of CO that I'm aware of, batteries are outside of the cabin, nothing sprayed, etc.

I had a DC powered CO detector that was sensitive to voltage drops and would alert because of it. Unlikely related but something to note.