Spirax Sarco LCS3051 User manual

IM-P693-07 EMM Issue 2 1
LCS3051 High Water Level Switch
850147-01
LCS3051
High Water Level Switch
Installation and Maintenance Instructions
IM-P693-07
EMM Issue 2
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

IM-P693-07 EMM Issue 2
2
LCS3051 High Water Level Switch

IM-P693-07 EMM Issue 2 3
LCS3051 High Water Level Switch
1. Safety information
High water level alarms 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 LCS3051 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!
Important
The name plate specifies the technical features of the equipment. Note that any piece
of equipment without its specific name plate must neither be commissioned nor
operated.
1.1 Directives and Standards
Pressure Equipment Directive (PED) 2014/68/EU
The level switch LCS3051 in conjunction with level probe LP41 is 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 according to IEC 61508
The level switch LCS3051 is certified according to IEC 61508 only if used in combination with level
probe LP41. This standard describes the functional safety of safety-related electrical/electronic/
programmable electronic systems.
The equipment combination LP41 + LCS3051 corresponds to a type B subsystem with Safety
Integrity Level (SIL) 2.
VdTÜV Bulletin “Wasserstand 100” (Water Level 100)
The level switch LCS3051 in conjunction with the level probe LP41 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 LCS3051 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 LCS3051 must not be used in
potentially explosive areas.

IM-P693-07 EMM Issue 2
4
LCS3051 High Water Level Switch
Note
The level probe LP41 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 LP41 + Zener barriers +
LCS3051 are interconnected!
1.2 Functional Safety according to IEC 61508
Safety characteristics of the subsystem LP41/LCS3051
The level switch LCS3051 is certified acc. to IEC 61508 only if used in combination with level probe
LP41.
The equipment combination LP41/LCS3051 corresponds to a type B subsystem with Safety Integrity
Level (SIL) 2. 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 LP41/LCS3051 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 LP41/LCS3051 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 21oo2 20 20
SFF PFDav PFHav λ DU
Level switch LCS3051 in
conjunction with one level
probe LP41
>90% <5 x 10-3 <5 x 10-7 <5 x 10-7/h

IM-P693-07 EMM Issue 2 5
LCS3051 High Water Level Switch
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
λDU 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 contactors 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 %

IM-P693-07 EMM Issue 2
6
LCS3051 High Water Level Switch
2. General product information
2.1 Intended use
The level switch LCS3051 is used in conjunction with level probe LP41 as high level alarm in steam boilers
and (pressurised) hot-water plants.
A high level alarm prevents the water level from exceeding the preset max. water level (HW) and for this
purpose switches off e. g. the feedwater supply.
2.2 Function
The level switch LCS3051 is designed for connecting one level probe. See section Schematic representations
of arrangements on page 10.
When the water level exceeds the MAX limit, the level probe enters the liquid and an alarm is triggered in the
level switch. This switchpoint is determined by the length of the probe rod (level probe LP41).
After the de-energizing delay has elapsed, both output contacts of the level switch will open the safety circuit,
e. g. for the feedwater supply. If the deactivation of the feedwater supply is interlocked in the external safety
circuit, the lockout can only de deactivated when the level probe is exposed again.
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 safet y functions of the level switch. In the event of a malfunction
the safety circuit opens instantaneously and switches off e. g. the feedwater supply.
Alarm and malfunction messages are indicated by LEDs, and the signal output is instantaneously energized.
An alarm can be simulated by pressing the test button.
Fig. 1
Note
A high level alarm prevents the water level from exceeding the preset max. liquid level
( H W ) . F o r t h i s p u r p o s e i t c a n , f o r i n s t a n c e , i n t e r r u p t t h e f e e d w a t e r s u p p l y . I f t h e i n t e r r up t i o n
of the feedwater supply endangers the heating surfaces in the feedwater preheater
(economizer), the heating must be switched o󰀨, too.

IM-P693-07 EMM Issue 2 7
LCS3051 High Water Level Switch
3.1 Dimensions (approximate) in mm
3. Mechanical installation
Item
1Upper terminal strip
2Lower terminal strip
3Fixing screws (cross recess head screws M3)
4Enclosure
5Supporting 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.
5
100
73
118
32
1
4

IM-P693-07 EMM Issue 2
8
LCS3051 High Water Level Switch
Alarm Signal
24 VDC
100 mA
CEP
Tamb =55°C (131°F)T
7 W IP 40 (IP20)
0525
250V
T 2,0A
TÜV.SHWS.XX-XXX
20 21
3sec.
10 µS/cm
2
LP 41
32 1
134516 17 23 24 26 27
LCS3051
MAX M 0,5A
4-393314-02
LCS3051
High Water Level Limiter
Level Switch
Niveauschalter
Commutateur de niveau
Functional safety
IEC 61508
SIL 2
MADE IN GERMANY
24 V=
24 V
±20%
See installation
instructions
Betriebsanleitung
beachten
Voir instructions de
montage
AL
+
_
+
_
3.2 Installation in control cabinet
The level switch LCS3051 is clipped onto the support rail 7 type TH 35, EN 60715 in the control cabinet.
Name-plates
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.SHWS.XX-XXX
Serial number

IM-P693-07 EMM Issue 2 9
LCS3051 High Water Level Switch
2716
12345678
17 18 19 20 21 22 23 24
9
25
10
26
11 12
28
13
29
14
30
15
4. Electrical installation
Item
1Power supply
2Signal output 1 for external alarm 24 Vdc, 100mA (semiconductor output)
3Safety circuit, input and output
4Wire link, fitted on site, when used as high water level alarm acc. to EN 12952/EN 12953
5CEP Central earthing point in control cabinet
6Level probe LP41.
Fig. 4
4.1 Wiring diagram
1 2
3
4
3
6LP41
5

IM-P693-07 EMM Issue 2
10
LCS3051 High Water Level Switch
Item
1Level probe LP41
2Level switch LCS3051
3Safety circuit
Steam boiler plants according to EN 12952-07/EN 12953-06, 72 h operation
Fig. 5 Combination consisting of 1 level probe LP41 and 1 level switch LCS3051 as high water level alarm.
Functional safety IEC 61508, SIL 2.
Further applications in accordance with national sets of regulations
Fig. 6 Combination consisting of 1 level probe LP41 and 1 level switch LCS3051 as high water level alarm.
The level switch opens two separate safety circuits. Functional safety IEC 61508, SIL 2.
4.3 Connection of supply voltage
Provide the level switch LCS3051 with an external semi-delay fuse 0.5 A.
Danger
For the supply of the level switch LCS3051 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 electrical
isolation).
4.4 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 terminal 5 and to the
central earthing point (CEP) in the control cabinet.
4.2 Schematic representations of arrangements
Fig. 5 Fig. 6
12
3
12
3