Siemens LGA41.153A27 User manual

CC1N7418en
08.04.2004
Siemens Building Technologies
HVAC Products
7418
Gas Burner Controls LGA...
The LGA... are used for the startup and supervision of atmospheric gas burners
of small to medium capacity (without fan) in intermittent operation.
The LGA... and this Data Sheet are intended for use by OEMs which integrate the
gas burner controls in their products.
Use
The flame is supervised with an ionization probe.
Using the appropriate adapters, the LGA... can replace their predecessor types LFI7...
and LFI5... in terms of function and size (refer to «Ordering»).
LGA41.173A27 and LGA52.171B27 are suited for use with direct-fired air heaters.

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Warning notes
To avoid injury to persons, damage to property and the environment, the follow-
ing warning notes should be observed!
Do not open, interfere with or modify the unit.
•All activities (mounting, installation and service work, etc.) must be performed by
qualified staff
•Before performing any wiring changes in the connection area of the LGA..., com-
pletely isolate the burner control from the mains supply (all-polar disconnection)
•Ensure protection against electric shock hazard by providing appropriate protection
for the burner control’s connections terminals
•Check to ensure that wiring is in an orderly state
•Press the lockout reset button / operating button only manually (applying a force of
no more than 60 N), without using any tools or pointed objects
•Fall or shock can adversely affect the safety functions. Such units may not be put
into operation even if they do not exhibit any damage
Mounting notes
•Ensure that the relevant national safety regulations are complied with
•The ionization probe and ignition electrode must be positioned such that the igni-
tion spark cannot arc over to the ionization probe
•The position and polarity of the ignition electrode can adversely affect the magni-
tude of the flame signal. Reversal of polarity of the ignition transformer’s connec-
tions on the primary side usually solves the problem
•Since the burner bars form the earthed counter-electrode, the burner must be ad-
justed such that the flame is hot and stable and in firm contact with the burner bars.
With pulsating flames or yellow-burning flames resulting from lack of air, a very low
or even no ionization current is generated so that the burner control will initiate
lockout
Installation notes
•To isolate the burner control from the mains supply, use an all-polar switch with a
contact gap of at least 3 mm
•Secure the earthing lug in the terminal base with a metric screw and a lockwasher
or similar
•Switches, fuses, earthing, etc., must be in compliance with local regulations; pri-
mary fuse max. 10 A (slow)
•Make absolutely certain that life and neutral conductors are correctly connected to
terminals 1 and 2 of the burner control; otherwise, no flame signal will be generated
•Connect the gas pressure switch and other monitoring devices - whose contacts
must be closed from startup to controlled shutdown - in series with «R» and «W»
•If the fully closed position of the main gas valve «BV2» shall be checked on burner
startup, the closed position contact must be included in the loop between terminals
9 and 3. In addition, the connecting links between terminals 9 and 11 and 8 and 3
must be fitted
•During the startup sequence, terminal 6 carries voltage and may not be used as an
auxiliary terminal
•The auxiliary contact of a gas valve for checking the fully closed position must be
included in the loop between terminals 9 and 3
•During the startup sequence, terminals 9 and 6 carry voltage and may not be used
as auxiliary terminals
•Connect the load controller of 2-stage burners to terminal 5 in series with «BV2»
Siting the ionization
probe
Only with LGA41...
Only with LGA52... /
LGA63...

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Electrical connection of ionization probe
It is important to achieve practically disturbance- and loss-free signal transmission:
•Never run the detector cable together with other cables
– Line capacitance reduces the magnitude of the flame signal
– Use a separate cable
•Observe the permissible length of the detector cable (refer to «Technical data»)
•The ionization probe is not protected against electric shock hazard
•Locate the ionization probe such that the ignition spark cannot arc over (risk of
electrical overloads)
•Always run the high-voltage ignition cables separate from the unit and other cables
while observing the greatest possible distances
•The insulation resistance between ionization probe and ground must be a minimum
of 50 MΩ, even after a large number of operating hours.
Prerequisite for this is not only high quality heat-resistant insulation of the cable,
but also of the ionization probe itself (ceramic holder!)
•A soiled ionization probe holder offers favorable conditions for surface leakage cur-
rents which reduce the magnitude of the flame signal
•The burner (as the counter-electrode) must be correctly earthed, or else no ioniza-
tion current will flow
Earthing the boiler alone does not suffice!
•The connection diagrams shown apply to burner controls with earthed neutral con-
ductor. In the case of ionization current supervision in networks with nonearthed
neutral conductor, terminal 2 must be connected to the earth conductor via an RC
unit (part no. ARC 4 668 9066 0). In that case, it must be made certain that the
relevant national safety regulations are complied with (e.g. electric shock hazard
protection), since AC 230 V / 50 Hz mains voltage results in a leakage current of
2.7 mA
Commissioning notes
•Prior to commissioning, check to ensure that wiring is in an orderly state
•When commissioning the plant or when doing maintenance work, make the follow-
ing safety checks:
Safety check Anticipated response
a) Burner startup with no flame signal; for
that purpose, open the connection be-
tween burner control and ionization
probe prior to burner startup and main-
tain that status
Lockout at the end of «TSA»
b) Burner operation with simulated loss of
flame during operation; for that purpose,
open the connection between burner
control and ionization probe during
burner operation and maintain that
status
Restart, followed by lockout at the
end of «TSA»
c) No air pressure signal during «t1» (only
with LGA52... / LGA63... with fan) No startup
d) Air pressure failure during operation
(only with LGA52... / LGA63... with fan) Shutdown

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Standards and certificates
Conformity to EEC directives
– Electromagnetic compatibility EMC (immunity)
- Directives for gas-fired appliances
89 / 336 EEC
90 / 396 EEC
ISO 9001: 2000
Cert. 00739 ISO 14001: 1996 Cert. 38233
LGA41.153A27 --- ---
LGA41.173A27 x x
LGA52.150B17 x ---
LGA52.150B27 x ---
LGA52.171B27 x x
LGA63.191A27 x ---
•Identification code to EN 298
- A M C L X N single-stage
- A T C L X N 2-stage
Service notes
•Each time a unit has been replaced, check wiring to ensure that it is in an orderly
state and make the safety checks as indicated in «Commissioning notes»
Disposal notes
The unit contains electrical and electronic components and may not be disposed of to-
gether with household waste.
Local and currently valid legislation must be observed.
Mechanical design
The gas burner controls are of plug-in design, suitable for installation in any position on
burners, in control cabinets or on control panels.
The housing is made of impact-proof, heat-resistant plastic and accommodates:
- The thermal sequencing device (ambient temperature-compensated) acting on a
multiple snap action switching system,
- The flame signal amplifier with the flame relay, and
- The lockout warning lamp and lockout reset button (splash-proof)
In the event mains voltage drops below about AC 165 V, an electronic circuit ensures
that the gas burner control will prevent burner startup or – without releasing fuel – lock-
out will be initiated.
•Undervoltage threshold: AC 178 V ±10 V
•«TSA»: Smaller tolerance band
•Flame signal amplifier: Higher sensitivity, for typical applications with pilot flames
LGA...
Undervoltage detection
Only with
LGA63.191A27

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Type summary
The type references given in the table refer to burner controls with no base and no ac-
cessories.
AC 230 V --- --- --- --- LGA63.191A27
AC 220...240 V --- LGA41.173A27 LGA52.150B27 LGA52.171B27 ---
Burner with
undervoltage detection AC 100...110 V --- --- LGA52.150B17 --- ---
Burner without AC 220...240 V LGA41.153A27 --- --- --- ---
undervoltage detection AC 100...110 V --- --- --- --- ---
Connection facility for auxiliary fan ¹) --- --- x x x
Connection facility for air pressure switch --- --- x x x
Control outputs for gas valves 2 2 2 2 2
Reversed polarity protection x x x x x
1) Auxiliary fan not monitored to EN 298
Ordering
Gas burner control (without plug-in base) refer to «Type summary»
Electrical connections refer to Data Sheet 7201
- Plug-in base AGK11...
- Cable holders AGK65..., AGK66, AGK67...
- Cable strain relief elements for AGK67...
Electrical connections refer to Data Sheet 7203
- Plug-in base AGK13...
- Plug-in housing AGK56
- Cover AGK68
Ionization probe supplied by thirds
Pedestal AGK21
- For increasing the height of the LGA... to that of the LFI1... or LFI5...
RC unit (for the supervision of ionization currents in networks with nonearthed neutral
conductor) ARC 4 668 9066 0

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Technical data
Mains voltage
- Only with LGA63...
AC 220 V −15 %...AC 240 V +10 %
AC 100 V –15 %...AC 110 V +10 %
AC 230 ±10 %
Mains frequency 50...60 Hz ±6 %
Power consumption 3 VA
Input current at terminal 1 max. 5 A
Perm. electrical rating
- Terminals 4 and 8
- Terminals 6, 7 and 9
- Terminals 5 and 10
max. 4 A
max. 2 A
max. 1 A
External primary fuse max. 10 A (slow)
Degree of protection IP 40 (when integrated)
Perm. mounting position optional
Weight approx. 180 g
Transport DIN EN 60 721-3-2
Climatic conditions class 2K2
Mechanical conditions class 2M2
Temperature range -50...+60 °C
Humidity < 95 % r.h.
Operation DIN EN 60 721-3-3
Climatic conditions class 3K5
Mechanical conditions class 3M2
Temperature range 0...+60 °C
for LGA41.173A27 and LGA52.171B27:
-20...+60 °C
Humidity < 95 % r.h.
Condensation, formation of ice and ingress of water are not permitted!
Voltage between ionization probe and
ground mains voltage
Required detector current min. 5 µA
Possible detector current max. 100 µA
Length of detector cable max. 20 m (separate cable)
Required insulation resistance between
ionization probe with its cable and ground min. 50 MΩ
General unit data
Environmental
conditions
Flame supervision with
ionization probe

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Function
(times in seconds) 1)
AC 220...240 V LGA41.153A27 LGA41.173A27 LGA52.150B27 LGA52.171B27 LGA63.191A27
AC 100...110 V --- --- LGA52.150B17 --- ---
t1 Prepurge time --- --- approx. 13 approx. 13 approx. 13
t3 Preignition time 15 15 --- --- ---
t3´ Preignition time from start of «TSA» --- --- max. 5 4.5...7.5 max. 10
TSA Ignition safety time 5 10 5 4.5...7.5 10
TSAmax. Max. ignition safety time 10 20 10 20 20
t3n Postignition time max. 2 max. 2 --- --- ---
t4 Interval «BV1 – BV2» approx. 18 approx. 13 approx. 18 approx. 13 approx. 23
¹) All times specified apply to AC 220 V and AC 110 V respectively
For AC 240 V operation, above times are to be multiplied by 0.7
Fault Response of LGA41... Response of LGA52... / LGA63...
Erroneous flame signal during «t1»
or «t3» Lockout ²) prior to the release of gas Lockout ²) prior to ignition and the re- lease of gas
No flame on completion of «TSA» Lockout ²) Lockout ²)
Loss of flame during operation Repetition Repetition
No air pressure signal during «t1» --- No start
Air pressure failure during operation --- Shutdown
²) After lockout, the burner control can be reset after about 60...90 seconds
The conductivity and rectifying effect of hot flame gases are used for flame supervision.
For that purpose, AC voltage is applied to the ionization probe which projects into the
flame.
The current that flows in the presence of a flame (ionization current) generates the
flame signal which is then fed to the input of the flame signal amplifier.
The amplifier is designed such that it only responds to the DC current component of the
flame signal, thus ensuring that a short-circuit between ionization probe and ground
cannot simulate a flame signal (since in that case, AC current would flow).
Control sequence
Control sequence in the
event of fault
Flame supervision with
ionization probe

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When the switch-on command is given, power is supplied to the ignition transformer
and the heating coil of the bimetal sequencing device.
The bimetal bends and pushes contact set «c, d, e» towards «f».
On completion of the preignition time, the system tilts so that «e - f» closes and «f - g»
opens, «BV1» receives voltage.
Contacts «c - d» still remain closed («c» resting on «d»).
On flame establishment, the flame relay is energized, latching mechanically «e - f» in
the position now assumed.
The relay also closes contact «f» and, at the same time, opens «c - d», so that the igni-
tion transformer and the bimetal heating element will be switched off.
Then, «d» slowly returns to its starting position, also catching «g».
When tilting back, «g - f» closes, so that the main gas valve «BV2» will be energized.
If no flame signal is generated, the flame relay does not open «c - d», so that the bi-
metal will continue to be heated.
The bimetal thus continues to bend until – tilting – it actuates contact «tz2»: →Lockout.
In the event of an erroneous premature flame signal, the flame relay – by means of its
latch – prevents «e - f» from making, which means no release of gas.
«TZ», however, still receives power so that the bimetal continues to bend until, eventu-
ally, lockout is initiated by «tz2».
EK
1
SB
W
R
L
N
210
AL
91183 76 45 12
Z BV1 BV2 ION
7418i02/0304
LGA41...
L1 tz2
XYZab
fr
TZ
cde
tz1 fg
FR
Si H
AL Fault status signal R Thermostat or pressurestat
BV... Fuel valve SB Safety limit thermostat
EK Lockout reset button Si External primary fuse
ION Ionization probe TZ Electro-thermal timer
FR Flame relay (bimetal system) with contacts «tz»
L1 Built-in lockout warning lamp W Limit thermostat
H Main switch Z Ignition transformer
Internal diagram
LGA41...
Legend

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When the switch-on command is given, the auxiliary fan starts to run.
When the air pressure switch closes its contact, the heating coil of the bimetal sequenc-
ing device is energized and the bimetal pushes contact set «c, d, e» towards «f»
(thereby opening «f - g»).
On completion of the prepurge time, «e - f» is closed so that both gas valve «BV1» and
the ignition transformer receive voltage: The safety time starts.
On flame establishment, the flame relay latches mechanically «e - f», pushes «c» back
at the same time and opens «fr».
The ignition transformer is thus switched off and the heating coil deenergized, so that
«d» can revert to its starting position.
When tilting back, «g - f» closes so that the main gas valve «BV2» receives voltage.
If no flame signal is generated, the flame relay does not open «c - d», so that the bi-
metal will continue to be heated.
The bimetal thus continues to bend until – tilting – it actuates contact «tz2»: →Lockout
In the event of an erroneous premature flame signal, the flame relay – by means of its
latch – prevents «e - f» from making, which means no release of gas.
«TZ», however, still receives power so that the bimetal continues to bend until, eventu-
ally, lockout is initiated by «tz2».
EK
1210 8711 9 6 4 5 12
7418i01/0304
SB
W
R
L
N
AL M1) Z
LP
BV1 ION
L1
XYZ
tz2 ab
fr
TZ
cde
tz1 fg
FR
LGA52... / 63...
BV2
Si H
AL Fault status signal H Main switch
BV... Fuel valve M Auxiliary fan
EK Lockout reset button R Thermostat or pressurestat
ION Ionization probe SB Safety limit thermostat
FR Flame relay Si External primary fuse
L1 Built-in lockout warning lamp TZ Electro-thermal timer
LP Air pressure switch (bimetal system) with contacts «tz»
W Limit thermostat
1) Not monitored to EN 298 Z Ignition transformer
Internal diagram
LGA52... / LGA63...
Legend

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Connection diagram Control sequence
12 911 837 4 5 106
LGA41...
FR
W
R
L
N
ZAL ION
7418a04/0304
SB
BV1 BV2
12
Si
H
SB
R/W
Z
BV1
BV2
FS
1
7
4
5
12
t3 t3n
TSA
t4
ABCD
7418f01/0200
12689 11 74510 12
LGA52... / 63...
SB
W
R
L
N
M1)
LP
ZAL ION
BV1 BV2
FR
7418a05/0304
Si
H
SB
R/W
LP
M
9
6
Z
BV1
BV2
FS
t1 t3´
TSA
t4
1
11
8
9
6
7
4
5
12
AB CD
7418f02/0200
AL Fault status signal M Auxiliary fan
BV... Fuel valve R Thermostat or pressurestat
ION Ionization probe SB Safety limit thermostat
FR Flame relay Si External primary fuse
FS Flame signal W Limit thermostat
LP Air pressure switch Z Ignition transformer
H Main switch
Required input signals 1) Not monitored to EN 298
Burner control’s output signals
A Commencement of startup sequence C Operating position
B Time of flame establishment D Controlled shutdown by «R»
t1 Prepurge t3n Postignition
t3 Preignition time t4 Interval «BV1 – BV2»
t3´ Preignition time from the start of «TSA» TSA Ignition safety time
Legend

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Dimensions Dimensions in mm
5,5
62,5
88
91
41,5
47
62,5
7418m04/0204
22
xxxxxxxxxx
LGA...
©2004 Siemens Building Technologies Production GmbH
Subject to change