Routine Maintenance - Crowcon Xgard IR Instrucciones De Instalación, Funcionamiento Y Mantenimiento

3. Operation
9. Allow the gas reading to stabilise (usually 30 to 60 seconds) and adjust the 'CAL'
pot until the DVM reads the appropriate reading (eg for a hydrocarbon gas detector
120 mV = 12 mA = 50% LEL). If the concentration of the calibration gas used is not
50% of scale, the following formula can be used to calculate the reading:
 
160
 
 
× Gas   +
 
Range
 
Example: calibrating a 0-5% CO
 
160
 
 
3 40
×   + =

 
5
10. If the control equipment display requires adjustment consult the operating manual for
the equipment.
11. Remove the gas and allow the sensor to completely settle before re-checking the
zero setting.
12. Close the junction box of the detector ensuring that the lid is securely tightened, and
the grub-screw is secured.
13. The detector is now operational.
Note: ATEX certified Xgard flammable gas detectors will be supplied calibrated for com-
pliance with EN60079-20-1 (where for example 100% LEL methane = 4.4% volume).
UL certified detectors will be supplied calibrated for compliance with North American
standards (where 100% LEL methane = 5% volume).

3.2 Routine maintenance

Site practices will dictate the frequency with which detectors are tested. Crowcon would
recommend that detectors be gas tested at least every 6 months and re-calibrated as
necessary. To re-calibrate a detector follow the steps given in 3.1.
The sinter should be inspected regularly, and replaced if it has become contaminated. A
blocked sinter may prevent gas from reaching the sensor.
When performing maintenance on Xgard IR, ensure that the sensor retainer and junc-
tion box lid O-rings are present and in good condition to maintain the ingress protection
of the product. See the 'Spare parts and accessories' section for the part numbers of
replacement O-rings.
The sensor used in Xgard IR should provide in excess of 5 years trouble-free operation.
In the event of a sensor failure, the sensor module should be replaced.
14
40 = mV setting
detector using 3% CO
2
136 mV
test gas
2
Xgard IR