29
WARNING
Prior to carrying out any work ensure local regulations and
site procedures are followed. Never attempt to open the
detector or junction box when flammable gas is present.
Ensure that the associated control panel is inhibited so as to
prevent false alarms.
3.1
Commissioning procedure
1. Open the junction box of the detector by unscrewing the lid in an anti
clockwise direction (having loosened the retaining grubscrew first).
2. Check that all electrical connections have been made and are correct
as per Diagram 9.
3. Measure the voltage across the ‘+’ and ‘’ terminals and adjust
according to the type of pellistor fitted (see Table 3).
4. Leave the detector to stabilise for at least 1 hour.
5. Balance the WB circuit at the control panel if necessary. Refer to the
control equipment instruction manual.
Zeroing the detector
6. Ensure you are in clean air. Adjust the control equipment to read zero.
Calibrating the detector
7. Apply calibration gas (concentration should be 50% LEL) to the
detector at a flow rate of 0.5 1 litre/minute via a flow adaptor (
Part
No. C03005
). Contact Crowcon for the supply of calibration gas.
8. Allow the gas reading to stabilise (usually 30 to 60 seconds) and adjust
the control equipment to read 50% LEL.
9. Remove the gas and allow the sensor to completely settle before re
checking the zero setting.
10.Close the junction box of the detector ensuring that the lid is securely
tightened, and the grubscrew is secured.
11.The detector is now operational.
Note:
ATEX certified Xgard flammable gas detectors will be supplied
calibrated for compliance with IEC 61779 (where for example 100% LEL
methane = 4.4% volume). UL/CSA certified detectors will be supplied
calibrated for compliance with ISO 10156 (where 100% LEL methane =
5% volume).
3. Operation
Xgard Type 3
