6
9 - Operation and in-service Test
When the BLS 9200 is installed and in normal operation there is no requirement for user interven-
tion. Operation is fully automatic where the switch will respond to the presence of liquid which
causes the internal float to rise and operate the internal reed switch causing it to change state.
Likewise, when the liquid level reduces below the switch position the BLS 9200 will automatically
reset and the reed switch again change state.
For in-service test purposes the BLS9200 has an integral test handle. This handle may be used
to simulate the presence of liquid to check that the switch operates as expected.
Gently lifting the handle upwards will cause the internal float to lift which will in turn cause the
reed switch to changeover.
When the handle is released the float will reset to its alarm off position.
To confirm correct operation use a multi-meter or other continuity tester to check that there is a
closed circuit between normally closed and common when the float is at rest, and between nor-
mally open and common when the float is manually lifted by the test handle.
10 - Maintenance needs
The BLS9200 has been designed for long and maintenance free operation. There are no specific
service requirements, and no need for lubrication or other consumables.
As a precautionary measure it is recommended that the switch is visually inspected on a periodic
basis to ensure that it remains free from contamination, and that operation and free movement of
the internal float is confirmed by lifting of the test handle as detailed in the preceding section. This
may also be used to validate alarm reporting on the remote monitoring system.
It is recommended that this inspection is undertaken on a monthly to quarterly basis. .
If it is required to specifically test the function and correct operation of the switch in respect of its
changeover action, then this should be undertaken when it is not immersed by first disconnecting
the output cables and connecting the continuity meter across the common and normally closed
terminals. This should show continuity.
Next the switch should be operated by lifting the handle to confirm that contact is broken between
common and normally closed.
The test should then be repeated for the common and normally open contact by ensuring that
when the switch is in its active position (lifted) that there is continuity and that there is no continui-
ty when the switch handle is released.
