Ask the experts
Q
We fitted a CO detector when we had a gas stove on our GK24. The gas stove was replaced with an alcohol stove and the CO detector started going off immediately we lit up the alcohol.
It turns out that CO detectors are also directly sensitive to ethanol vapour.
They have a filter membrane on some designs to slow response but eventually they will go off just on ethanol.
Reading technical documentation on CO detectors shows this is a well known problem.
So at the moment CO detectors are useless on a boat with an alcohol stove while cooking. What would be useful is one with a 1 hour cancel button so it continues to monitor for CO at other times from diesel heaters and engine exhausts.
PETER SPREADBOROUGH REPLIES:
All electrochemical CO sensors have some cross sensitivity to other chemicals that include ethanol, ISO-propanol, acetone and hydrogen. The quality of the sensor will determine the degree of cross sensitivity.
ECO-Sure sensors are regarded as one of the best sensors in the market. These are used on industrial as well as domestic/leisure alarm systems. The Honeywell X70 alarm also has a ‘Hush’ feature that will silence the alarm for a few minutes, but having this feature for an hour could prove deadly, so no alarm would have that included.
It may be worth relocating the alarm to somewhere away from the stove at a midpoint between the floor and ceiling and increasing the amount of ventilation in the galley.