CO detector trips from gas refrigerator and oven pilot

[Jammer]

Well folks I'm proceeding with the systems repairs and checks on my C-11.

Had all pilots lit... furnace, water heater, oven ... and fridge running on gas. Left overnight in my storage location and my tenant in the house nearby called to say that there was intermittent beeping. I went out to check and found the CO detector showing 70 ppm.

I suspect that it tripped once the fridge had cooled down and the gas burner in the fridge had been put on low flame by the thermostat. I had left the bottom trim piece off, that covers up the controls, and put that back on. Rechecked after an hour and CO was down to around 40 ppm.

Shut off the oven pilot, rechecked after an hour, and CO detector was showing 0.

I'll clean burners and adjust air shutters but am wondering whether others have run into this and what they ended up finding.

[slowmover]

Is this a question about airflow/ventilation in that a closed space with no windows or doors open allowed some minor accumulation? On a normal day of camping wouldn't the windows and door provide relief after lighting off appliances?

[Jammer]

True enough during a typical day. On a cold night there could be a problem.

[azflycaster]

FYI, CO levels and exposure issues...
CO exposure chart

[Jammer]

Originally Posted by azflycaster

FYI, CO levels and exposure issues...
CO exposure chart

Not sure of the source. The OSHA permissible exposure limit is 50 ppm for an 8 hour workday.

[JFScheck]

Still - what if the furnace was running and one was inside all day long such as in the mountains but the fridge side is on the sunny side so it is still running?

Of course - guess I'm being a bit weird here, point is - what are the norms for the standard Airstreams? :-)

[Phoenix]

Is the pilot light on your oven "inside" the camper? Assuming it is, a window or vent must be left open to provide fresh air, the same as when the stove top burners are used.

Similarly, in any enclosed area, fresh air ventilation must be provided for any non-electric space heater, gas-fueled lantern (with mantle), candles or any similar appliance/device with an open flame that uses propane, CNG, white gas, etc.

Even if the device supposedly burns "cleanly" (i.e., it does not release carbon monoxide), carbon dioxide will still be produced, which will eventually displace all of the oxygen in the enclosed area, resulting in suffocation.

=====

Note to JFScheck: Newer models have gas appliances that use electronic ignition (i.e., do NOT have pilot lights). Therefore, under normal conditions, your furnace and refrigerator should not produce carbon monoxide inside your Airstream. However, when camping recently in subfreezing weather, our PROPANE alarm (not CO alarm) went off each time the propane tank ran low.

I think when the tank pressure is insufficient for the furnace to start and run, a little bit of raw propane gas leaks into the trailer from the heat exchanger when the burner is trying to light; and this sets off the alarm. So, in really cold weather, it is wise to keep your tanks full; and swap them out before they get down to about 1/3. That way you won't be awakened in the middle of the night.

Personally, we keep a window and ceiling vent cracked open about an inch or so to provide a little bit of fresh air, even in subfreezing weather -- just to be safe.

[Jammer]

Phoenix

I don't believe that pilot lights pose an oxygen depletion risk. They use less oxygen than my dog.

I'm mainly interested in the experience of others regarding CO detector trips. Anyone?

[tpi]

Could it be the missing trim piece, coupled with wind which blew the CO into the trailer?
I never had the problem, but I always wondered about a wind blowing combustion gas from fridge into trailer via improper sealing. Looking at mine I can't believe the fridge compartment is sealed all that well.

[Protagonist]

Originally Posted by Jammer

Not sure of the source. The OSHA permissible exposure limit is 50 ppm for an 8 hour workday.

From the EPA website at: Carbon Monoxide (CO) | Indoor Air | US Environmental Protection Agency there are actually three authoritative indoor air quality limits for carbon monoxide:

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for carbon monoxide is 50 parts per million (ppm) as an 8-hour time-weighted average (TWA) concentration —29 CFR Table Z-1.

The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for carbon monoxide of 35 ppm as an 8-hour TWA and 200 ppm as a ceiling —NIOSH 1992.
The NIOSH limit is based on the risk of cardiovascular effects.

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned carbon monoxide a threshold limit value (TLV) of 25 ppm as a TWA for a normal 8-hour workday and a 40-hour workweek [ACGIH 1994, p. 15]. The ACGIH limit is based on the risk of elevated carboxyhemoglobin levels —ACGIH 1991, p. 229.

Honestly, Permissible Exposure Limits have no bearing for us. Unless you intend to disable your alarm and continue breathing the stuff, or even worse, stay in your Airstream while the alarm is sounding and risk hearing loss as well, the NIOSH 200-ppm ceiling level (a "do not exceed, ever" level) is more important.

The Atwood CO detector in my Airstream Interstate will detect levels as low as 11 ppm, but will only display (and sound an alarm) when the level goes over 30 ppm. Yours is probably similar.

[Jammer]

Originally Posted by tpi

Could it be the missing trim piece, coupled with wind which blew the CO into the trailer?
I never had the problem, but I always wondered about a wind blowing combustion gas from fridge into trailer via improper sealing. Looking at mine I can't believe the fridge compartment is sealed all that well.

It was in a sheltered location so no wind, but the missing trim piece clearly played a role on the fridge end of things.

There is also the oven pilot to consider.

[slowmover]

Paint, cleaning chemical solutions, etc, will set off detectors. A "problem" in both of my trailers (until accummulation clears).

[Phoenix]

Quote from Jammer's original entry: "Rechecked after an hour and CO was down to around 40 ppm... Shut off the oven pilot, rechecked after an hour, and CO detector was showing 0."

I think you have answered your own question...

[Sodbust]

My Co2 buzzer goes off if I run one burner on the cook stove.. I truly believe its more that the EPA regs are about 100 times higher than what the old timers put up with before the EPA and CO2 buzzers.. I just pull my batteries out unless I'm sleeping..

Sodbust

[Jammer]

Rest of the story... Cleaned burners with compressed air and a little brushing, and the problem went away. However, high CO levels still occurred when operating the main burner on the oven. Turns out that someone used too long a screw to hold the air shutter in place on a previous repair, and it was interfering with the flow of gas. I cut down the screw with a die grinder and now there's no measurable CO.

[rumrunner]

assuming that the detector is working properly and your pilot is properly adjusted, have you checked your fridge venting? the pilot should not create excessive CO but it does still need a place to go. Maybe a nice quiet low draw puck fan ?
tim