BI620114
Service Manual
OPERATION OF THE BYPASS SWITCH Latching: When a high alarm level (1.25% Methane) is reached a relay will switch sending a signal to the electronic shutdown system which will hold the high alarm on (shutting down the machine). This high alarm level will remain on even when the electronic shutdown system is switched off, the power is cut or the methane drops to a safe level. The methane has dropped to a safe level when the low alarm indicator is off and high alarm indicator is still on. A high alarm condition will always shutdown the machine unless in bypass mode, see below. At this point the machine cannot be started until a supervisor with access key can unlock the box and rotate the switch clockwise (approximately 45°) and then back to the original position, the high alarm indicator will then go off. (The system must be on for this to work). Finally the system will then need to be restarted and then the machine can be started again. Other functionality:
Bypass: The rotary switch can be left in the on position (rotated 45° clockwise from the position it can be locked). This will bypass the methane sensor allowing the machine to be moved when the methane sensor is faulty.
Straight: The switch also has the option to run the machine without the locked high alarm. In this mode the electronic shutdown system will run how it has previous to this bypass switch e.g. If a high alarm level (1.25% methane) is reached the machine will shutdown, however when the alarm level drops below the 1.25% methane then the machine can be restarted, without need to unlock the switch.
Methane Bypass Switch
268
FBL-10 LHD/Utility Serial No. 1600
rev 2
