PSM BLS9200 Manuale
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PSM WEEE Producer Registration No WEE/HC0106WW
Installation Operation & Maintenance
Instruction Manual
BLS9200 Bilge/ Flood Detection Switch
Burrell Road Industrial Estate
Haywards Heath, West Sussex RH16 1TW, UK
PSM Document Reference: MAN 45 Issue K
Issue Date: April 2020
PSM INSTRUMENTATION LTD
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Part Index Page
1Introduction 3
2Storage and Environmental data 3
3Safety and Handling precautions 3
4Installation 3
5Electrical Connection 4
5.1 Optional Termination Enclosures 4
6Protection of the internal Reed Relay 5
7Lamp Loads 5
8Fitting Arc Suppression 5
9Operation and In-Service Test 6
10 Maintenance Needs 6
11 Repair 7
12 Specification - BLS 9200 7
13 Drawings 7
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1 - Introduction
The Bilge Switch Model BLS 9200 is designed to be installed in ships bilges and tanks, where it
is bolted in situ at the required alarm level. This switch is manufactured in corrosion resistant
stainless steel fully submersible construction with an hermetically sealed SPDT reed switch pot-
ted in epoxy.
The switch is also designed with a manual lift test mechanism to be used to check switch oper-
ation.
2 - Storage and Environmental Data
The BLS 9200 is a robust construction which is designed to withstand the in-service conditions
it will encounter. Where the switch is to be stored prior to installation and use normal precau-
tions must be taken to prevent the unit from mechanical damage and ingress of moisture into
the exposed cable end. Warehouse storage without secondary packaging is acceptable provid-
ed these precautions are taken and the actual storage conditions are clean and dry and within
the temperature range of 0°C to +40°C
3 - Safety and Handling Precautions
The BLS 9200 switch is a lightweight construction weighing less than 1Kg typically (depending
upon length of attached cable). No special precautions are necessary in the handling of the
switch other than to ensure that it is stored and handled appropriately to ensure that no me-
chanical damage can occur to either the switch, its attached test handle, and especially to the
outer sheathing of the attached cable. Note that the cable is permanently fixed to the switch
and no attempt should be made to remote it as this will compromise the integrity of the seals
used to ensure full submersibility.
4 - Installation
The BLS9200 is provided with an integral mounting bracket having 2 holes 9mm diameter on
44 mm centres.
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The nominal switch actuation point is at a dimension of 50mm below the mounting holes and ac-
tuates on a rising level, therefore in tank fixing should be located at a datum of 50mm above the
desired alarm actuation point.
The mounting arrangement should be rigid and not liable to vibration or flexing and it must be en-
sured that the BLS 9200, when mounted is vertical both when viewed from the side and the front.
If the switch is not mounted vertically there is a risk that the movement of the float will be imped-
ed.
The switch float is well protected by the perforated stainless steel shield but in general it should
be ensured that the selected location for installation is away from any area which is liable to col-
lect debris or other contaminants which could, over time, cause a build-up and / or blockage to
restrict the free movement of liquid to actuate the float.
5 - Electrical Connection
The BLS 9200 is manufactured with the cable permanently bonded to the body. No attempt
should be made to disconnect it. The actual length provided will have been specified at time of
manufacture to suit the duty.
If required it can be cut to length.
The conductors on the three core cable are labelled as indicated in the key below.
1 = Common
2= Normally Open
3 = Normally Closed
When the switch is not in alarm there is a circuit between Common and Normally Closed.
When the switch enters alarm mode there is a circuit between Common and Normally Open.
Refer to PSM drawing 170423-WD-001 for connection details
Once the electrical connections are completed correct operation of the switch can be validated
by using the test handle. Refer to the section “Operation and In Service Test” for details.
5.1 Optional Termination Enclosures
PSM provide three options for termination enclosures for the BLS 9200,
In Polycarbonate: BSE1 for a single switch, and BSE2 for two switches.
In Aluminium: BSE10 for a single switch
Protection: IP65 (all versions)
Refer to the drawings at the end of this manual for further details
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6 - Protection of the internal Reed Switch
Note: Attempting to put excessive power through the bilge switch will irreparably damage the
reed switch internals.
• If the power rating of the switch is greatly exceeded, the contacts will become perma-
nently welded together.
• If the switch is allowed to arc (spark) as it opens or closes the plated contacts will fail
over time. [ the greater the arc - the more rapidly failure will occur]
Do not be misled by the resistive ratings of the switches. Most applications involve inductive
loads and many low wattage loads are often high inductance devices.
Switches ratings are quoted for a resistive load. Suppression is important to protect the switch.
7 - Lamp loads
Incandescent lamp loads can be very destructive to reed switch applications.
These type of loads have a 6-10 times the normal operating current when first energised [inrush
current].
8 - Fitting ARC suppression
• For a DC circuit – a one amp diode should be placed in parallel with the load to suppress
the arc. Select a diode with a voltage rating of at least three times [3x] or more than that of
the circuit rating. Connect diode cathode to positive.
• For an AC circuit - a capacitor and resistor fitted in parallel with the switch. Use a 0.1mf
400-600V capacitor and a 50 to 100 ohm ¼ watt resistor in series with the capacitor.
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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.
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11 - Repair
The BLS9200 is a fully welded and sealed assembly which contains no user serviceable parts.
If a switch if found not to be operational after carrying out the tests detailed in the previous sec-
tion then it may be removed from its mountings and visually inspected.
If it appears that contamination within the protective shield is preventing free movement of the
float then the switch may be flushed using clean warm water or a mild solvent compatible with
stainless steel.
To assist in access for flushing, the bottom cover of the switch shield may be temporarily re-
moved, this is held in place by a circlip.
Removal of the switch will necessitate undoing of the two securing bolts and lifting the complete
switch away from the mounting removing any securing ties that have been used to retain the
switch cable.
Inverting the switch will show the circlip on the bottom of the central switch stem. This may be re-
moved using standard hand tools (small screwdriver of needle nosed pliers) . Once removed the
lower cover can be lifted away to carefully clean any sediment present.
Once cleaned the switch can be checked to determine the float actually operates by immersing in
a small container full of water and observing both the float and the action of the contacts as de-
tailed in the previous section.
If it is found that the float does not operate or that the contacts do not change state then then the
switch must be replaced as a complete assembly.
12 - Specification - BLS 9200
13 - Drawings
Refer to following pages
Materials All 316 Stainless Steel WIRING
Switch Rating: 100VA SPDT
Process Temp. -10 to +90C 1 = Common
Max load rating: 100W ac/dc resistive 2 = Normally Open
Max Current 3A 3 = Normally Closed
Min load rating: 3W
Max load volts: 500V dc / 250V ac
Float S.G. 0.62
NOTE: The actuation point can vary slightly depending on the temperature and specific
gravity of the individual liquid being detected
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