Riken Keiki GD-3EC, Technical Manual

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10. Product Specifications 10-3 Detection target gases for individual detection principles
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10-3-2 New ceramic type
Sensor model Gas name
Gas
symbol
F.S. 1 digit
First
Alarm
setpoint
Second
Alarm
setpoint
Calibration
gas
Operating
temperature
range
Operating
humidity
range
Years of
warranty
NCF-6318 Methane CH
4
100 %LEL 0.5 %LEL 25 %LEL 50 %LEL CH
4
*
2
−40 °C -
70 °C
0 %RH -
95 %RH*
1
(no
condensation)
3 years NCF-6319 VCM VCM 100 %LEL 0.5 %LEL 25 %LEL 50 %LEL i-C
4
H
10
NCF-6320 Hydrogen H
2
100 %LEL 0.5 %LEL 25 %LEL 50 %LEL H
2
* 3
*1: Absolute humidity not exceeding 46 g/m 3 (equivalent to 37 °C, 95 %RH)
*2: Use the NCF-6318 if methane calibration is required or when the detection target gas is methane, propane, or
ethane. The detection target gas overlaps for the NCF-6318 and NCF-6319. Use the NCF-6319 in cases other than
the above.
*3: Use the NCF-6320 if hydrogen selectivity is required.
NOTE
 Install in a location with stable conditions within the specified operating temperature range and free of
sudden fluctuations.
 The sensor characteristics may deteriorate significantly if silicone gases (organic silicone gases), halogen
gases, sulfide gases, or acid gases are present.
 A silicone removal filter and activated carbon filter are available as options.
 For models with a F.S. of 5,000 ppm or less, allow the product to warm up for at least 120 minutes in
clean air before performing zero calibration and span adjustment.
 For models with a F.S. of 5,000 ppm or less, the effects of ambient humidity and temperature fluctuations
will become more significant, and the zero point may drift. If this occurs, enable the zero follower function.
However, we recommend using a sensor with a different detection principle where gas is constantly
present. The zero follower function cannot be used under such conditions.
 The reading may change even for combustible gases other than the detection target gas.
 Readings may fall as oxygen concentrations decrease.
 Interference may occur if gases with high thermal conductivity, such as high-concentration CO
2
, Ar, or He,
are present as the base gas.
 In detecting gases with low vapor pressure by the suction method, the gas may form a mist when drawn
in from the high-temperature side and detected at the low-temperature side, possibly forming
condensation inside the sensor or causing clogging due to sintering. Keep vapor pressure in mind during
use.
 Perform maintenance if a warning appears while the life assessment or self-diagnostic function is active.
 Use the combustible gas sensor adapter when calibrating. Calibration accuracy may be reduced without
the combustible gas sensor adapter.
 Reading accuracy may be reduced if temperature fluctuations exceed ±40 °C with respect to ambient
temperature following zero calibration or span calibration. If this occurs, repeat zero calibration or span
adjustment.
 Readings may fluctuate if the product is subjected to strong external impact or vibration. If this occurs,
perform zero calibration and span adjustment.
 The zero point may fluctuate if the sensor comes into contact with high-concentration gas of 100 %LEL or
more continuously for extended periods. If this occurs, perform zero calibration and span adjustment.
 The sensor may be hot during replacement. Be careful to avoid burns when replacing the sensor. If the
sensor is hot, turn off the power and wait for it to cool.
 Regardless of the detection target gas, the warranty period for NCF sensors is 3 years.