ServiceNomad RV · Knowledge
RV CO Detector Alarm Sounding
Carbon monoxide (CO) is an odorless, colorless, deadly gas produced by incomplete combustion of propane, gasoline, or diesel fuel. When your RV CO detector sounds its alarm, it is detecting dangerous levels of carbon monoxide inside your living space. Unlike propane detectors that can sometimes false alarm from other gases, CO detectors are highly specific and should always be treated as a life-threatening emergency. Carbon monoxide poisoning kills quickly and without warning—symptoms include headache, dizziness, nausea, confusion, and loss of consciousness.
What Triggers a CO Alarm
CO detectors are calibrated to alarm when carbon monoxide reaches 70 ppm (parts per million) for one hour, or higher concentrations for shorter periods. Common sources of CO in RVs include malfunctioning furnaces, water heaters, generators, or catalytic heaters operating with insufficient combustion air. CO is also produced by vehicle exhaust—if you're running the generator or idling the motorhome engine with the RV closed up, CO can infiltrate the living space. CO is produced when fuel burns without enough oxygen—this happens when burners are dirty, air intakes are blocked, exhaust flues are restricted, or the appliance is simply malfunctioning. It's invisible and odorless, which is why detectors are critical.
Immediate Actions When CO Alarm Sounds
If the CO detector alarms, take these steps immediately: (1) Evacuate everyone from the RV into fresh air. Move upwind from the RV and away from any running generator or engine. (2) Do not re-enter the RV to retrieve belongings—CO can render you unconscious in minutes at high concentrations. (3) Turn off all propane and fuel-burning appliances from outside if possible. Shut down the generator and engine. (4) Call 911 if anyone is experiencing symptoms of CO poisoning (headache, nausea, dizziness, confusion). (5) Ventilate the RV by opening windows and doors, and allow at least 30 minutes of fresh air circulation before cautiously re-entering. Do not reset the alarm and continue using the RV. The source of CO must be identified and repaired by a qualified technician before it's safe to occupy the space again.
Common CO Sources in RVs
Furnaces are the most common source of CO in RVs, especially if the burner is dirty, the heat exchanger has cracked, or the exhaust flue is blocked. A cracked heat exchanger allows combustion gases (including CO) to enter the living space instead of venting outside. Water heaters can also produce CO if the burner is sooted or the flue is obstructed. Generators running too close to the RV or with exhaust systems that leak can introduce CO into storage bays or through floor vents. A technician will use a CO analyzer to measure CO levels in the exhaust of each appliance and check for leaks in heat exchangers, flue pipes, and exhaust systems. They'll clean burners, inspect combustion chambers, and verify proper draft and airflow.
CO Detector Lifespan and Replacement
CO detectors have a limited lifespan, typically 5-7 years, because the electrochemical sensor degrades over time. An aging detector may alarm falsely or, worse, fail to alarm when CO is present. Always check the manufacture or expiration date on your CO detector and replace it when it reaches end-of-life. Many modern RV detectors combine propane and CO sensing in one unit. Replacement is straightforward—most are 12V powered and mount with screws. Test your CO detector monthly by pressing the test button and replace batteries (if equipped) annually.
⚠️ Safety Notes
- NEVER ignore a CO detector alarm—carbon monoxide kills quickly and without warning. Evacuate immediately and call for help.
- Symptoms of CO poisoning mimic flu or food poisoning—if multiple people in the RV feel sick simultaneously, suspect CO and evacuate.
- NEVER run a generator or engine in an enclosed space or with the RV windows closed—CO can reach lethal levels within minutes.
Can't fix it yourself?
Don't let a mechanical issue ruin your trip. Connect with vetted mobile RV technicians who can come to your location and get you back on the road.