The catalytic bead combustible gas sensor in the MX6 iBrid requires a minimum of 10% oxygen to provide an accurate reading. In any situation in which the oxygen reading is less than 10%, the combustible gas reading must be considered to be in error. The MX6 can also utilize one of two infrared (IR) sensors to detect combustible gas to 100% LEL or methane to 100% of volume. The infrared sensors do not rely on oxygen and therefore function accurately in an oxygen-deﬁcient atmosphere. It must be noted that the infrared sensors will not respond to hydrogen. In applications in which hydrogen is present and there is less than 10% oxygen, a 1:1 dilution ﬁtting must be used in the sample line to provide sufﬁcient oxygen to the sensor and get an accurate reading. When using a dilution ﬁtting, the user must always remember that the monitor will display one-half of the actual gas concentration being measured.