RKI Instruments M2 Series - Manual (Page 11)

M2 Transmitter Operator’s Manual 6
Catalytic Detectors
The catalytic LEL detectors have a 1/2” NPT thread and require a 3/4”NPT x 1/2”NPT
reducer to install in the detector hub. The rest of the detectors have a 3/4” NPT mounting
thread and are installed directly in the detector hub.
IR Detectors
The IR combustible detectors are generally used instead of the catalytic combustible
detectors in applications where there may be catalyst poisons such as silicone present or
where oxygen is not present in the monitoring environment.
Oxygen Detectors
There are four types of oxygen detectors available, a non-explosion proof partial pressure
type, a non-explosion proof capillary type, a non-explosion proof capillary type with a
replaceable sensor, and an explosion proof (CSA) capillary type with a replaceable sensor.
The capillary type’s output is less susceptible to variations in atmospheric pressure than
the partial pressure type. The CSA type oxygen detector (65-2514RK) and one of the non-
explosion proof capillary type detectors (65-2494RK) have a replaceable plug-in sensor
inside the detector housing while the entire oxygen detector must be removed if
replacement is required for the other two.
Figure 2: 65-2514RK Oxygen Detector, CSA
SO
2
, 0 - 6 ppm • 65-2300RK-SO2
Table 2: M2 Detectors
Target Gas, Range Detector(s) Used
Flame Arrestor
Guard
Detector Housing Cap
Oxygen Sensor
Detector Housing Body
Cap Gasket