Why does my ToxCO have a red cross?
If the gas has expired or the gas cylinder is empty, you should get in touch with your distributor to purchase a replacement cylinder.
Check that the vent hole is not blocked because this will affect the calibration and it will fail.
If the sensor fails, you will need to get in touch with your distributor to arrange a sensor replacement or service.
If the problem persists or has not been resolved by the information provided above, please contact Bedfont or your local distributor for more advice.