Spirax Sarco LCS3050 User manual

IM-P693-06 EMM Issue 1 1
LCS3050 Low Water Level Switch for two probes
LCS3050
Low Water Level Switch for two probes
Installation and Maintenance Instructions
IM-P693-06
EMM Issue 1
850146-00
1. Safety information
2. General product information
3. Mechanical installation
4. Electrical installation
5. Commissioning
6. Fault finding
7. Technical information
8. Technical assistance
© Copyright 2020
Printed in Germany

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LCS3050 Low Water Level Switch for two probes

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LCS3050 Low Water Level Switch for two probes
Water level limiters are safety devices and must only be installed, wired and commissioned by
qualified and competent staff. Incorrect installation, wiring or commissioning can impact the safe
operation of the device.
Retrofitting and maintenance work must only be performed by qualified staff who – through adequate
training – have achieved a recognised level of competence.
Danger
The terminal strips of the equipment are live during operation! There is a risk of
serious injury due to electric shock!
Always cut off the power supply to the equipment before installing, removing or
connecting terminal strips!
Important
The name plate specifies the features of the equipment. Do not commission or operate
any item of equipment that does not have its own specific name plate.
1.1 Directives and Standards
Pressure Equipment Directive (PED) 2014/68/EU
Water level limiters are safety accessories as defined in the Pressure Equipment Directive (PED).
The level switch LCS3050 in conjunction with level probe LP40 are EU type approved according to
EN 12952/EN 12953. These Directives state, among other things, the requirements made on limiting
systems and equipment for steam boiler plants and (pressurised) hot-water installations.
Functional Safety acc. to IEC 61508
The level switch LCS3050 is certified acc. to IEC 61508 only if used in combination with level probe
LP40. This standard describes the functional safety of safety-related electrical/electronic/
programmable electronic systems.
The equipment combination LP40 + LCS3050 corresponds to a type B subsystem with Safety
Integrity Level (SIL) 3.
VdTÜV Bulletin “Wasserstand 100” (Water Level 100)
The level switch LCS3050 in conjunction with the level probe LP40 is type approved according to
the VdTÜV Bulletin “Water Level 100”.
The VdTÜV Bulletin “Wasserstand (Water Level) 100” specifies the requirements made on water
level control and limiting equipment for boilers.
LV (Low Voltage) Directive and EMC (Electromagnetic Compatibility)
The level switch LCS3050 meets the requirements of the Low Voltage Directive 2014/35/EU and the
EMC Directive 2014/30/EU.
ATEX (Atmosphère Explosible)
According to the European Directive 2014/34/EU the level switch LCS3050 must not be used in
potentially explosive areas.
1. Safety information

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LCS3050 Low Water Level Switch for two probes
Note
The level probe LP40 is a simple item of electrical equipment as specied in EN 60079-
11 section 5.7. According to the European Directive 2014/34/EU the equipment must be
equipped with approved Zener barriers if used in potentially explosive areas. Applicable
in Ex-zones 1, 2 (1999/92/EC).
The equipment does not bear an Ex marking.
Note: The requirements of the IEC 61508 are not met if the LP40 + Zener barriers +
LCS3050 are interconnected!
1.2 Functional Safety according to IEC 61508
Safety characteristics of the subsystem LP40/LCS3050
The level switch LCS3050 is certified acc. to IEC 61508 if used in combination with level
probe LP40.
The combination LP40/LCS3050 corresponds to a type B subsystem with Safety Integrity Level
(SIL) 3. Type B means that the behaviour under fault conditions of the used components cannot
be completely determined. The functional safety of the equipment combination refers to the
detection and evaluation of the water level and, as a consequence, the contact position of the
output relays.
The design of the equipment combination LP40/LCS3050 corresponds to the architecture 1oo2.
This architecture consists of two channels that detect and diagnose faults in each other. If a fault
is detected, the equipment combination LP40/LCS3050 will go to the safe state, which means that
the contacts of both output relays will open the safety circuit.
Table 1
Safety characteristics SIL Architecture Lifetime (a) Proof Test
Interval (a)
General 31oo2 20 20
SFF PFDav PFHav λ DU
Level switch LCS3050 in
conjunction with two level
probes LP40
>90% <5 x 10-4 <5 x 10-8 <10 x 10-8

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LCS3050 Low Water Level Switch for two probes
1.3 Terms and abbreviations
Table 2
Terms/Abbreviations Description
Safety Integrity Level/SIL Classification of the Safety Integrity Level acc. to IEC 61508
Lifetime (a) Functional safety: Lifetime in years
Safe Failure Fraction/SFF Percentage of failures without the potential to put the safety-
related system into a dangerous state
Probability Failure per Demand
(Low Demand)/PFDav
Average probability of failure on demand for low demand
mode (once a year)
Probability Failure per Hour/PFHav Probability of failure per hour
DU Failure rate for all dangerous undetected failures (per hour)
of a channel of a subsystem
Determination of the Safety Integrity Level (SIL) for safety-related systems
Level probe, level switch and actuators (auxiliary contactor in safety circuit) are subsystems and
together constitute a safety-related system that executes a safety function.
The specification of the safety-related characteristics Table 1 refers to the level probe and the level
switch including the output contacts. The actuator (e. g. an auxiliary contactor in the safety circuit)
is installation specific and, according to IEC 61508, must be considered separately for the whole
safety-related system.
Table 3 shows the dependence of the Safety Integrity Level (SIL) on the average probability of
failure on demand of a safety function for the whole safety-related system (PFDsys). The “Low
demand mode” is here considered for a water level limiter, which means that the frequency of
demands for operation of the safety-related system is no greater than one per year.
Table 3
Low demand mode PFDsys Safety Integrity Level (SIL)
≥ 10 -5 ... < 10 -4 4
≥ 10 -4 ... < 10 -3 3
≥ 10 -3 ... < 10 -2 2
≥ 10 -2 ... < 10 -1 1
Table 4 indicates the attainable Safety Integrity Level (SIL) as a function of the Safe Failure Fraction
(SFF) and the Hardware Fault Tolerance (HFT) for safety-related systems.
Table 4
Hardware Fault Tolerance (HFT) for type B Safe Failure Fraction (SFF)
012
SIL 1 SIL 2 < 60 %
SIL 1 SIL 2 SIL 3 60 % - < 90 %
SIL 2 SIL 3 SIL 4 90 % - < 99 %
SIL 3 SIL 4 SIL 4 ≥ 99 %

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LCS3050 Low Water Level Switch for two probes
2.1 Intended use
The level switch LCS3050 is used in conjunction with level probe LP40 to limit the water level in steam boilers
and (pressurised) hot-water plants.
Water level limiters switch off the heating when the water level falls below the set minimum level (low water).
2.2 Function
The level switch LCS3050 is designed for connecting one or two level probes. See section Schematic
representations of arrangements on page 10.
When the water level falls below the low level the level probes are exposed and a low level alarm is triggered
in the level switch. This switchpoint is determined by the length of the probe rod (level probe LP40).
After the de-energizing delay has elapsed, the two output contacts of the level switch will open the safety
circuit for the heating. The switching-off of the heating is interlocked in the external safety circuit and can
only be deactivated when the level probe enters the water again.
In addition, two signal outputs for external signalling devices close instantaneously.
An alarm will also be raised if a malfunction occurs in the level probe and/or the electrical connection.
An automatic self-testing routine monitors the safety functions in the level switch and the level probes. In the
event of a malfunction the safety circuit opens instantaneously and switches the heating off.
Alarm and error messages are indicated by LEDs and a signal output for each level probe is energized
without delay.
An alarm can be simulated by pressing the test button.
2. General product information
Fig. 1

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LCS3050 Low Water Level Switch for two probes
3.1 Dimensions (approximate) in mm
3. Mechanical installation
Item
1Upper terminal strip
2Lower terminal strip
3Fixing screws (cross recess head screws M3)
4Code switch for switching on/off level probe 1/2
5Code switch for switching on/off level probe 1/2
6Enclosure
7Supporting rail type TH 35, EN 60715
Fig. 2
The code switches are accessible after removing the lower terminal strip. The terminal strips can be unplugged
after undoing the right and the left fixing screws.
7
100
74
120
5
32
1
6
4

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LCS3050 Low Water Level Switch for two probes
3.2 Installation in control cabinet
The level switch LCS3050 is clipped onto the support rail 7 type TH 35, EN 60715 in the control cabinet.
Name-plate
LCS3050
Alarm Signal
24 VDC
100 mA
CEP
Low Water Level Limiter
Tamb = 55°C (131°F)T
IP 40 (IP20)
7 W
0525
250V
T 2,0A
TÜV.SWB.XX-XXX
Level Switch
Niveauschalter
Commutateur de niveau
20
29
21
30
3sec.
Functional safety
IEC 61508
SIL 3
10 µS/cm
9
2
LP 40
1
2
3
1345
10 11 12 13 16 17 23 24 26 27
LCS3050
MIN
24 V
±20%
M 0,5A
4-393313-02
+
MADE IN GERMANY
See installation
instructions
Betriebsanleitung
beachten
Voir instructions de
montage
24 V=
AL 1
AL 2
AL 1
AL 2
+
_
_
AL 1 AL 2
1Safety note
2Wiring diagram
3Manufacturer
4Type designation
5Supply voltage/Protection
6Ambient temperature / sensitivity
7Safety circuit
8Wire link,provided on site
9Fuse, provided on site
10 Type approval no.
11 Disposal note
Fig. 3
1
2
3
6
5
8
7
4
9
10
11
TÜV.SWB.XX-XXX

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LCS3050 Low Water Level Switch for two probes
4. Electrical installation
Item
1Supply voltage
2Signal output 1/2 for external alarm 24 Vdc, 100 mA (semiconductor output)
3Safety circuit, input and output
4Wire link, on site, when used as water level limiter according to EN 12952 / EN 12953
5CEP Central earthing point in control cabinet
6Level probe LP40.
Fig. 4
4.1 Wiring diagram
2716
12345678
17 18 19 20 21 22 23 24
9
25
10
26
11 12
28
13
29
14
30
15
++-
M 0,5A
(+) (-) -
1
2
31
2
3
1 2
3
4
3
2
6LP40 LP40
5 5
6

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LCS3050 Low Water Level Switch for two probes
Item
1Level probe(s) LP40
2Level switch LCS3050
3Safety circuit
4Level switch LCS3050 for low-level pre-alarm
4.2 Schematic representations of arrangements
Fig. 5 Fig. 6
Fig. 7 Fig. 8
Fig. 9 Fig. 10
12
3
4
1
1 1
1 1
2
2 2
2 2
3
3 3
3 3

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LCS3050 Low Water Level Switch for two probes
4.3 Explanatory notes to schematic representations
Fig. 5
Steam boiler plants according to EN 12952-07/ EN 12953-06, 72 h operation
Combination consisting of 2 level probes LP40 and 1 level switch LCS3050 as water level limiter.
Functional safety IEC 61508, SIL 3. The equipment combination meets the demand for two
independent water level limiters.
Fig. 6
(Pressurised) hot-water plants and electrically heated steam boilers according to EN 12953-06.
Steam boiler plants with high availability according to EN 12952-07 / EN 12953-06, 72h operation.
Combination consisting of 1 level probe LP40 and 1 level switch LCS3050 as water level limiter.
Functional safety IEC 61508, SIL 3. Hot water installations require two independent and separate
water level limiters. For this purpose one equipment combination LP40/LCS3050 shall be installed
in the hot-water boiler and the second one in the pressure maintaining vessel, the expansion tank
or the like (depending on the type of pressurisation). For electrically heated steam boilers one water
level limiter is sufficient. To meet the plant operator's demand for a higher level of availability of
the steam boiler plant, two (or three) independent equipment combinations LP40/LCS3050 can be
installed in the steam boiler.
Fig. 7
Combination consisting of 1 level probe LP40 and 1 level switch LCS3050 as water level limiter. The
level switch opens two separate safety circuits. Functional safety IEC 61508, SIL 3.
Further applications in accordance with national sets of regulations
Fig. 8
Combination consisting of 2 level probes LP40 and 1 level switch LCS3050 as water level limiter.
The level switch opens two separate safety circuits. Functional safety IEC 61508, SIL 3.
Further applications in accordance with national sets of regulations
Fig. 9
Combination consisting of 1 level probe LP40 and 1 level switch LCS3050 as water level limiter and 1
level probe LP40/1 level switch LCS3 050 as first low- level alarm. Functional safety IEC 61508, SIL 3.
Further applications in accordance with national sets of regulations
Fig. 10
Combination consisting of 2 level probes LP40 and 2 level switches LCS3050 as water level limiter.
The level switch opens two separate safety circuits. Functional safety IEC 61508, SIL 3.
Further applications in accordance with national sets of regulations
Note
Please observe the safety-related characteristics for the equipment combination 1 level
probe LP40/level switch LCS3050 and 2 level probes LP40/level switch LCS3050 on
Table 1.
4.4 Supply voltage
Provide the level switch LCS3050 with an external semi-delay fuse 0.5 A.
Danger
For the supply of the level switch LCS3050 with 24 Vdc use a safety extra-low voltage
(SELV) power supply unit that must be electrically isolated from dangerous contact
voltages and must meet at least the requirements on double or reinforced isolation
acc. to EN 50178, EN 61010-1, EN 60730-1, EN 60950-1 or EN 62368-1 (safe isolation).

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LCS3050 Low Water Level Switch for two probes
4.5 Connection of level probe
To connect the level probe please use screened multi-core control cable, min. conductor size 0.5 mm2, e.g.
LiYCY 4 x 0.5 mm2, max. length 100 m.
Wire terminal strip in accordance with the wiring diagram. Fig. 4. Connect screens to terminals 5 and 13 and
to the central earthing point (CEP) in the control cabinet.
4.6 Connection for signal output
A signal output for the connection of further external signalling equipment is allocated to each monitoring
channel in the level switch, max. load 100 mA. For connecting the level switch with the signal output unit
use a control cable, 2 x 0.5 mm2. In the event of an alarm or error message the signal outputs (terminals 20,
21 and 29, 30) close instantaneously.
4.7 Connection of safety circuit
Connect the safety circuit for the heating to terminals 23, 24 and 26, 27. When used as water level limiter
according to EN 12952 / EN 12953, connect the output contacts of the two monitoring channels by adding
a wire link between the terminals 24 and 26.
Provide the output contacts with a 2 A or 1 A (for 72 hours operation) slow-blow fuse.
Note
In the event of an alarm the level switch LCS3050 does not interlock automatically. If a
lock function is required by the installation it must be provided in the follow-up circuitry
(safety circuit). The circuitry must meet the requirements of the EN 50156.
Important
-Provide the level switch LCS3050 with an external semi-delay fuse 0.5 A.
-Connect screens to terminals 5 and 13 and to the central earthing point (CEP) in
the control cabinet.
-To protect the switching contacts provide the safety circuit with a slow-blow fuse
2 A or 1.0 A (for 72 hrs. operation acc. to TRD 604).
-When switching off inductive loads, voltage spikes are produced that may impair
the operation of control and measuring systems. Connected inductive loads
must be provided with suppressors such as RC combinations as specified by
the manufacturer.
-When used as water level limiter according to EN 12952 / EN 12953 connect
terminals 24 and 26 by adding a wire link.
-Install connecting lines to level probes and logic unit separated from power cables.
-Do not use unused terminals as support point terminals.
4.8 Tools
Screwdriver for slotted screws, size 3.5 x 100 mm, completely insulated according to VDE 0680-1.

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LCS3050 Low Water Level Switch for two probes
5.1 Factory setting
-De-energizing delay: 3 sec (factory set).
-Configuration: Operation with two level probes LP40. S1/S2 of code switches 4 and 5 set to OFF.
Danger
The terminal strips of the LCS3050 are live during operation. This presents the
danger of electric shock!
Always cut off power supply to the equipment before mounting, removing or
connecting the terminal strips!
Changing the function of the level switch
If only one probe is used for operation (e. g. in case of emergency operation) change the settings as follows:
-Switch off supply voltage.
-Unscrew the right and left fixing screws 3 and remove the lower terminal strip 2, Fig. 2.
-Depending on which probe shall be deactivated, set S1/S2 of code switches 4 and 5 to ON.
-Attach lower terminal strip and fasten fixing screws.
-Apply supply voltage, equipment is re-started.
4
Toggle switch, white
5
Toggle switch, white
Code switch 4 Code switch 5
S 1 S2 S 1 S2
Level probe 1 activated OFF OFF
Level probe 1 deactivated ON ON
Level probe 2 activated OFF OFF
Level probe 2 deactivated ON ON
Note
If only one level probe is switched on, only the LEDs for power and alarm of the
corresponding channels will be illuminated.
5. Commissioning

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LCS3050 Low Water Level Switch for two probes
5.2 Checking switchpoint and function
Level probe 1
Test and diagnosis button
Level probe 2
Test and diagnosis button
LED alarm 1 /operating mode LED alarm 2 /operating mode
Diagnosis LED
Fig. 11
Start
Activity Indication Function
Apply supply voltage.
All LEDs are illuminated.
System is being started and tested, this
takes approx. 10 sec.
Output contacts are open.
Signal outputs 1 and 2 are closed.
All LEDs are illuminated for more
than 10 sec.
System malfunction. Possible causes: Faulty
power supply, level switch defective.
Raise water in boiler until the
switchpoint “low water level (LW)”
is exceeded. Level probe(s) make(s)
contact with the water.
Green LEDs for level probe 1/2
illuminated.
Output contacts are closed. Signal outputs 1
and 2 open.
Checking switchpoint and function
Lower water level until it is below
the switchpoint “low water level
(LW)”. Level probe(s) is/are exposed.
Red LEDs for level probe 1/2 are
flashing.
De-energizing delay is running. Signal
outputs 1 and 2 are closed instantaneously.
Red LEDs for level probe 1/2
illuminated.
Delay time has elapsed, output contacts
open. Signal outputs 1 and 2 are closed.
Possible installation faults
Status and indication Fault Remedy
Sightglass indicates level below
switchpoint “low water (LW)”,
red LEDs for level probes 1/2 not
illuminated. Safety circuit closed.
Probe rod(s) is/are too long. Cut probe rod(s) to the length dictated by the
switchpoint LW.
If installed inside the boiler:
Upper vent hole in protection tube
does not exist or is obstructed.
Check installation of level probe. Make
sure that the level in the protection tube
corresponds to the actual water level.
Water level sufficient. Red LEDs for
level probes 1/2 illuminated! Safety
circuit open.
Probe rod(s) is/are too short. Replace probe rod(s) and cut new rods to the
length dictated by the switchpoint LW.
The earth connection to the
vessel is interrupted.
Clean probe threads and ensure excessive
PTFE tape has not been applied.
Electrical conductivity of the
boiler water too low. Correct water conductivity.
Upper vent hole flooded.
Check installation of level probe. Make
sure that the level in the protection tube
corresponds to the actual water level.

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LCS3050 Low Water Level Switch for two probes
5.3 Operation
Level probe 1
Test and diagnosis button
Level probe 2
Test and diagnosis button
LED alarm 1 /operating mode LED alarm 2 /operating mode
Diagnosis LED
Fig. 12
Operation
Activity Indication Function
Level probe(s) submerged. Green LEDs for level probe 1/2
illuminated.
Output contacts are closed. Signal
outputs 1/2 open.
Alarm
Level probe(s) exposed, level below
low water level (LW).
Red LEDs for level probe 1/2 are
flashing.
De-energizing delay is running.
Signal outputs 1/2 are closed
instantaneously.
Red LEDs for level probe 1/2
illuminated.
Delay time has elapsed, output
contacts open. Signal outputs 1/2 are
closed.
Test channel 1 and 2
During operation:
Press key 1 or 2 and hold it down until
the end of the test, level switch must
react as if there was an alarm.
Red LEDs for level probe 1/2 are
flashing.
Alarm simulated in channel 1 or 2.
De-energizing delay is running.
Signal outputs 1/2 are closed
instantaneously.
Red LEDs for level probe 1/2
illuminated.
Delay time has elapsed, output
contacts open. Signal outputs 1/2 are
closed.
Test finished.

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LCS3050 Low Water Level Switch for two probes
6. Fault finding
6.1 Display, diagnosis and troubleshooting
Important
Before carrying out the fault diagnosis please check:
Supply voltage
Is the level switch supplied with the voltage specified on the name plate?
Wiring
Is the wiring in accordance with the wiring diagram and the relevant schematic
representation of arrangement?
Configuration
Are the code switch settings 4 and 5 correct for the number of level probes used?
Fault indication
Status Diagnosis Function Next activity
Faulty evaluation of level
probe 1, channel 1
Diagnosis LED 1 and LED
alarm 1 illuminated.
Output contacts are opened
instantaneously.
Signal output 1 closes
instantaneously.
next:
Press key AL1.
Faulty evaluation of level
probe 2, channel 2
Diagnosis LED 2 and LED
alarm 2 illuminated.
Output contacts are opened
instantaneously.
Signal output 2 closes
instantaneously.
next:
Press key AL2.
Malfunction in level switch
detected.
Diagnosis LED 3 and LED
alarm 1 and 2 illuminated.
Output contacts are opened
instantaneously.
Signal outputs 1 and 2 are
closed instantaneously.
next:
Press key AL1 or key AL2.

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LCS3050 Low Water Level Switch for two probes
Diagnosis
Display 1 and activity Display 2 Fault Remedy
LED alarm 1 and diagnosis
LED 1 illuminated. Press and
hold down key AL1.
Diagnosis LED 1 flashing.
Malfunction in level probe 1,
malfunction in level switch,
faulty wiring,
faulty measuring voltage.
–
–
–
–
check wiring,
measure probe voltages,
clean and, if necessary,
exchange level probe,
exchange level switch.
Diagnosis LED 2 flashing.
Malfunction in level probe 1,
malfunction in level switch,
faulty wiring.
Diagnosis LED 3 flashing.
Interference voltage causing
malfunction, boiler earth
without PE
Provide screen and
earthing, connect boiler
with PE.
LED alarm 2 and Diagnosis
LED 2
illuminated. Press and hold
down key AL2
Diagnosis LED 1 flashing.
Malfunction in level probe
2, malfunction in level
switch, faulty wiring, faulty
measuring voltage.
–
–
–
–
check wiring,
measure probe voltages,
clean and, if necessary,
exchange level probe,
exchange level switch.
Diagnosis LED 2 flashing.
Malfunction in level probe 2,
malfunction in level switch,
faulty wiring.
Diagnosis LED 3 flashing.
Interference voltage causing
malfunction, boiler earth
without PE.
Provide screen and
earthing, connect boiler
with PE.
LED alarm 1 and 2 and
Diagnosis LED 3
illuminated. Press and hold
down key AL1 or AL2.
Diagnosis LED 1 flashing. Malfunction in processor
Replace level switch.
Diagnosis LED 2 flashing. Internal voltage fault.
Diagnosis LED 3 flashing. Malfunction in relay.
Once the fault is eliminated, the level switch returns to normal operation.
After elimination of the fault switch off the supply voltage and switch it on again after approx. 5 sec.

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LCS3050 Low Water Level Switch for two probes
6.2 Measuring voltage across level probe
Measure the probe voltage in order to check whether the level probe is immersed or if there is a malfunction.
Please observe Figure 13.
U2-4/10-12
U3-4/11-12 U2-3/10-11
immersed exposed Malfunction (immersed/ alarm)
≈ 0.7 V
85 Hz! <
U2-4/10-12
≥
U2-4/10-12 ≤ U3 - 4 /11 -1 2
2 2
Item
1CEP Central earthing point in control cabinet
2Level probe LP40.
Fig. 13
Note
The self-checking routine of the level switch LCS3050 reduces U2-4/10 -12 to 0 Volt, if
executed cyclically.
1 2 345678 9 10 11 12 13 14 15
1
2
31
2
3
U2-4
U2-3
U3-4
U10-12
U10-11
U11-12
1 1
2LP40 LP40 2

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LCS3050 Low Water Level Switch for two probes
6.3 Emergency operation for water level limiter
If the level switch LCS3 050 works with t wo level probes LP40 (water level limiter to EN 12952-07, EN 129 5 3 - 0 6),
the installation can continue operating in emergency operation mode according to EN 12952 and EN 12953
under constant supervision with only 1 level probe, in case that one of the two installed level probes fails.
If only one probe is used for operation change the settings as follows:
-Switch off supply voltage.
-Unscrew the right and left fixing screws 3 and remove the lower terminal strip 2. See Figure 2.
-Depending on which probe shall be deactivated, set S1 or S2 of code switches 4 and 5 to ON.
-Attach lower terminal strip and fasten fixing screws.
-Apply supply voltage, equipment is re-started.
4
Toggle switch, white
5
Toggle switch, white
Code switch 4 Code switch 5
S1 S2 S1 S2
Level probe 1 activated OFF OFF
Level probe 1 deactivated ON ON
Level probe 2 activated OFF OFF
Level probe 2 deactivated ON ON
Important
-Record the beginning of emergency operation in the boiler log.
-An installation operating in emergency mode has to be constantly supervised.
-Immediately replace faulty level probe.
-Record the end of emergency operation in the boiler log.
-When the emergency operation is over, restore original settings.
If faults occur that are not listed above or cannot be corrected, please
contact our service centre or authorized agency in your country.

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LCS3050 Low Water Level Switch for two probes
6.4 Action against high frequency interference
Should sporadic failures occur in installations susceptible to faults (e. g. malfunctions due to out-of-phase
switching operations) we recommend the following actions in order to suppress interferences:
-Provide inductive loads with RC combinations according to manufacturer's specification to ensure
interference suppression.
-Make sure that connecting cables leading to the level probes are segregated and run separately from
power cables.
-Increase the distance to sources of interference.
-Check the connection of the screen to the central earthing point (CEP) in the control cabinet.
-HF interference suppression by means of hinged-shell ferrite rings.
6.5 Interlock and interlock deactivation
In the event of an alarm the level switch LCS3050 does not interlock automatically.
If a lock function is required by the installation it must be provided in the follow-up circuitry (safety circuit).
The circuitry must meet the requirements of the EN 50156.
6.6 Checking the switchpoints
To check the switchpoint “Low water (LW)” you have to lower the water level. When the water level falls
below the probe tip, the level switch must activate an alarm and the safety circuit must open as soon as the
de- energizing time delay has elapsed. The switching-of f of the heating is interlocked in the safety circuit and
can only be deactivated when the level probe enters the water again. In this case the LEDs for alarm 1 and
2 must be illuminated and no malfunction must be indicated (diagnosis LEDs are not illuminated). Always
check the switchpoint when commissioning the equipment, after replacing the level probe and at regular
intervals, e.g. every year.
6.7 Decommissioning/replacing level switch
-Switch off supply voltage and cut off power supply to the equipment.
-Unscrew the right and left fixing screws 3 and remove the upper and lower terminal strips 1, 2.
See Figure 2.
-Release the white fixing slide at the bottom of the equipment and take the equipment off the supporting rail.
6.8 Disposal
For the disposal of the level switch observe the pertinent legal regulations concerning waste disposal.