7 435

Burner Controls LGB...

Burner controls for the supervision of 1- or 2-stage gas or gas / oil burners of
small to medium capacity (typically up to 350 kW), with or without fan, in intermit-
tent operation.

The LGB... and this Data Sheet are intended for use by OEMs which integrate the
burner controls in their products!

Use
The LGB... burner controls are used for the startup and supervision of 1- or 2-stage gas
or gas / oil burners in intermittent operation.
Depending on the type of burner control used, the flame is supervised either by an
ionization probe, a blue-flame detector QRC1... for forced draft gas / oil burners, or a
UV detector QRA... (with auxiliary unit AGQ1...A27).

In connection with the respective adapters, the LGB... burner controls replace their
predecessor types LFI7... and LFM1... (also refer to «Replacement types» under «Or-
dering»).

- Automatic forced draft burners for gaseous fuels to EN 676

- Gas burner controls to EN 298
- Undervoltage detection
- Air pressure supervision with function check of the air pressure switch during
startup and operation
- Electrical remote reset facility
- LGB41... for use with atmospheric gas burners

CC1N7435en
Building Technologies
11.01.2007 HVAC Products
Warning notes
To avoid injury to persons, damage to property or the environment, the following
warning notes should be observed!

Do not to 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 LGB..., com-
pletely isolate the burner control from the mains supply (all-polar disconnection)
• Ensure protection against electric shock hazard by providing adequate protection
for the burner control’s connection terminals
• Each time work has been carried out (mounting, installation, service work, etc.),
check to ensure that wiring is in an orderly state and make the safety checks as
described in «Commissioning notes»
• Check to ensure that wiring is in an orderly state
• Press the lockout reset button only manually (apply a force of no more than 10 N),
without using any tools or pointed objects
• Fall or shock can adversely affect the safety functions. Such units must 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

Installation notes
• Always run the ignition cables separate from the unit and other cables while ob-
serving the greatest possible distance
• Do not mix up live and neutral conductors
• Install switches, fuses, earthing, etc., in compliance with local regulations
• Ensure that the maximum permissible current ratings will not be exceeded (refer to
«Technical data»)
• Do not feed external mains voltage to the control outputs of the unit. When testing
the devices controlled by the burner control (fuel valves, etc.), the LGB... must not
be connected
• 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 base with a metric screw and a lockwasher
• In the case of burners with no fan, the AGK25 must be connected to terminal 3 as
a burden, or else the burner cannot reliably start
• For safety reasons, feed the neutral conductor to the neutral distributor in the plug-
in base, or to terminal 2. Connect the burner components (fan, ignition transformer
and gas valves) as represented in the figure 7435a14, to the neutral distributor as
shown below. The connection between neutral conductor and terminal 2 is pre-
wired in the base

Exam- 2 3 7 4 5 Legend
ple V2
M
Z V1 V... Fuel valve
M Fan motor
N
7435a14/0601 Z Ignition transformer

Correct wiring of neutral conductors!

2/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Electrical connection of flame detectors
It is important to achieve practically disturbance- and loss-free signal transmission:
• Never run detector cables together with other cables
– Line capacitance reduces the magnitude of the flame signal
– Use a separate cable
• Observe the permissible length of the detector cables (refer to «Technical data»)
• The ionization probe and the ignition electrode are not protected against electric shock
hazard
• Locate the high-voltage ignition electrode and the ionization probe such that the ignition
spark cannot arc over to the ionization probe (risk of electrical overloads) and that it
cannot adversely affect the supervision of ionization
• With both ionization current and UV supervision, the cable length for flame detec-
tion must not exceed 20 m
• Insulation resistance
– Must be a minimum of 50 MΩ between ionization probe and ground
– Soiled detector holders reduce the insulation resistance, thus supporting cree-
page currents
– Prerequisite is not only high-quality heat-resistant insulation of the probe’s
cable, but also of the ionization probe itself (ceramic holder)
• Earth the burner in compliance with the relevant regulations; earthing the boiler
alone does not suffice
• The connection diagrams show the burner controls with earthed neutral conductor. In
networks with nonearthed neutral conductor and ionization current supervision, terminal
2 must be connected to the earth conductor via an RC unit (type reference
ARC 4 668 9066 0). It must be made certain that local regulations are complied with
(e.g. protection against electric shock hazard) since AC 230 V / 50 Hz mains voltage
produces peak leakage currents of 2.7 mA

Commissioning notes
• When commissioning the plant for the first time or when doing maintenance work,
make the following safety checks:

Safety check to be carried out Anticipated response

a) Burner startup with previously inter- Lockout at the end of «TSA»
rupted line to the ionization probe and
flame detector darkened in the case of
QRA... or QRC1...
b) Burner operation with simulated loss of Immediate lockout
flame. For that purpose, cut off the gas
supply (e.g. disconnect the fuel valve
while ensuring protection against elec-
tric shock hazard)
c) Burner operation with simulated air Immediate lockout
pressure failure (not with atmospheric
burners)

3/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Standards and certificates

Conformity to EEC directives

- Electromagnetic compatibility EMC (immunity) 89 / 336 / EEC
- Low-voltage directive 73 / 23 / EEC
- Directive for gas appliances 90 / 396 / EEC

ISO 9001: 2000 ISO 14001: 2004

Cert. 00739 Cert. 38233

• Identification code to EN 298

- LGB21... / LGB22... F T L L X N with 2-stage operation
- LGB32... F M L L X N with 2-stage operation
- LGB41... A B L L X N with 2-stage operation
(«BV1 + BV2» or «ZBV + BV2») A M L L X N with 1-stage operation

LGB21.130A17 x x --- ---

LGB21.130A27 x x x x
LGB21.230A27 x x x ---
LGB21.330A27 x x x ---
LGB21.350A17 x x --- ---
LGB21.350A27 x x x x
LGB21.550A27 x x x x
LGB22.130A27 x x x x
LGB22.230B27 x x x ---
LGB22.330A17 x x --- ---
LGB22.330A27 x x x x
LGB22.330A270 x x x ---
LGB32.130A27 x x x x
LGB32.230A17 x x --- ---
LGB32.230A27 x x x ---
LGB32.330A17 x x x ---
LGB32.330A27 x x x ---
LGB32.350A17 x x x ---
LGB32.350A27 x x x x
LGB41.255A27 x x --- x
LGB41.258A17 x x --- ---
LGB41.258A27 x x --- x

Service notes
• Use KF8872 service adapter for short periods of time only

Disposal notes
The unit contains electrical and electronic components and must not be disposed of
together with household waste.
Local and currently valid legislation must be observed.

4/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Mechanical design
The housing is made of impact-proof, heat-resistant and flame-retarding plastic.
It is of plug-in design (measuring 91 x 62 x 63 mm, including the base) and engages
audibly in the base.

The housing accommodates the

- programming mechanism with the synchronous motor
- electronic flame signal amplifier (ionization) with the flame relay and the other
switching devices
- lockout reset button with its integrated fault indication lamp

Type summary
The type references given below apply to LGB... burner controls without plug-in base
and without flame detector. For ordering information on plug-in bases and other acces-
sories, refer to «Mechanical design», «Ordering», «Flame supervision ...» and «Tech-
nical data».

Flame detector Type reference Approved in: tw/s t1/s TSA/s t3n/s t3/s t4/s t9/s t10/s t11/s t12/s t20/s
6) 3) 3)
ca. min. max. ca. ca. ca. max. min. max. max. ca.
Burner controls for 2-stage burners without control of actuator
Ionization probe (ION) LGB21.130A27 4)7) CH, EU, S, SF 8 7 3 2.4 2 8 --- 5 --- --- 6
or UV detector QRA... LGB21.230A27 5) CH, EU, S, SF 8 15 3 2.4 2 8 --- 5 --- --- 38
with AGQ1...A27 LGB21.330A27 5) CH, EU, H, S, SF 8 30 3 2.4 2 8 --- 5 --- --- 23
LGB21.350A27 5)7) CH, EU, H, S, SF 8 30 5 4 2 10 --- 5 --- --- 21
LGB21.550A27 5) AUS, CH, EU 8 50 5 4 2 10 --- 5 --- --- 2
Burner controls for 2-stage burners with control of actuator
Ionization probe (ION) LGB22.130A27 4) CH, EU, N, S 9 7 3 2.4 3 8 --- 4 12 12 21
or UV detector QRA... LGB22.230B27 5) CH, EU, N, S, SF 9 20 3 2.4 3 8 --- 4 16.5 16.5 2
with AGQ1...A27 LGB22.330A27 5)7) AUS, CH, EU, H, N, S, SF 9 30 3 2.4 3 8 --- 4 12 11 2
LGB22.330A270 5)8) EU 9 30 3 2.4 3 8 --- 4 12 11 2
Blue-flame detector LGB32.130A27 4)1) CH, EU 9 7 3 2.4 3 8 --- 4 12 12 21
QRC1... LGB32.230A27 5)1) CH, EU 9 20 3 2.4 3 8 --- 4 12 12 2
LGB32.330A27 5) CH, EU 9 30 3 2.4 3 8 --- 4 12 11 2
LGB32.350A27 5) CH, EU 9 30 5 4.4 1 10 --- 4 12 9 2
Burner controls for atmospheric burners
Ionization probe (ION) LGB41.255A27 EU 18 --- 5 4 2 10 5 --- --- --- 10
or UV detector QRA... LGB41.258A27 2)5)7) CH, EU, H, SF 18 --- 5 4 2 10 8 --- --- --- 10
with AGQ1...A27

Legend tw Waiting time 1) On request

t1 Prepurge time 2) For atmospheric burners up to 120 kW
TSA Ignition safety time 3) Maximum running time available for actuator
t3 Preignition time 4) Also suited for flash steam generators
t3n Postignition time 5) Also suited for stationary direct-fired air heaters
t4 Interval «BV1-BV2» or «BV1-LR» 6) «t9» + reaction time of flame relay
t9 Second safety time 7) Also available for AC 100...110 V; in that case, the last 2
t10 Specified time for air pressure signal digits read ...17 in place of ...27
t11 Programmed opening time for actuator «SA» 8) Without internal microfuse; must only be used in connection
t12 Programmed closing time for actuator «SA» with external microfuse 6.3 A (slow)!
t20 Interval up to self-shutdown of programming mechanism

5/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Ordering
Burner control, without plug-in base refer to «Type summary»

Connection accessories for small burner controls refer to Data Sheet N7201
- Plug-in base AGK11...
- Cable holders AGK65..., AGK66, AGK67...
- Cable strain relief elements for AGK67...

Connection accessories for small burner controls refer to Data Sheet N7203
- Plug-in base AGK13...
- Plug-in housing AGK56
- Accessories AGK68

Flame detectors
- Ionization probe supplied by thirds
- UV- flame detectors QRA2... / QRA10... refer to Data Sheet N7712
- Blue-flame detectors QRC1... refer to Data Sheet N7716

RC unit ARC 4 668 9066 0

For the supervision of ionization currents in networks with nonearthed neutral conductor

PTC resistor (AC 230 V) AGK25

To burden terminal 3 (mandatory when using burners with no fan
motor connected to terminal 3)

Auxiliary unit for UV supervision

- Cable length 500 mm AGQ1.1A27
- Cable length 300 mm AGQ1.2A27
- Can be fitted under the plug-in base (refer to «Dimensions»)

Pedestal (empty housing) AGK21

- For increasing the height of the LGB... to that of the LFM... or LFI7...

Service adapter KF8872

- For checking the functioning of the burner controls on the burner plant
- Functional test with signal lamps
- Detector resistance measurement with a jack of 4 mm diameter

Adapters / replacement types

No rewiring required
LGB21... with adapter KF8852 LFI7...

KF8880 LFM1... ¹)
LFM1...-F ¹)

LGB22... with adapter KF8853-K LFI7...

KF8880 LFM1... ¹)

LGB41... with adapter KF8862 LFM1... ¹)

¹) Designed only for ionization

6/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Technical data
General unit data Mains voltage AC 220 V –15 % ...AC 240 V +10 %
LGB... (LGB2... / LGB4...)
AC 230 V –15 % / +10 % (LGB32...!)
AC 100 V –15 % ...AC 110 V +10 %
Mains frequency 50...60 Hz ±6 %
Input current at terminal 12 max. 5 A
within the permissible voltage range
AC 187...264 V or AC 195...253 V
Current rating
- Terminal 3 max. 3 A (15 A for max. 0.5 s)
max. 2 A
- Terminals 4, 5 and 7 max. 1 A
- Terminals 9 and 10 max. 5 A
- Terminal 12 (at Umax. AC 264 V or AC 253 V)
Cable length terminals 8 and 10 20 m at 100 pF / m
Perm. cable lengths max. 3 m at 100 pF / m line capacitance
Detector cable laid separately 20 m
Power consumption 3 VA
Primary fuse max. 10 A (slow)
Degree of protection IP 40, when built in, with the exception of
the connection area (terminal base)
Mounting position optional
Weight approx. 230 g

Environmental conditions Storage DIN EN 60 721-3-1

Climatic conditions class 1K3
Mechanical conditions class 1M2
Temperature range -20...+60 °C
Humidity < 95 % r.h.
Transport DIN EN 60 721-3-2
Climatic conditions class 2K3
Mechanical conditions class 2M2
Temperature range -20...+60 °C
Humidity < 95 % r.h.
Operation DIN EN 60 721-3-3
Climatic conditions class 3K3
Mechanical conditions class 3M2
Temperature range -20...+60 °C
Humidity < 95 % r.h.

Condensation, formation of ice and ingress of water are not permitted!

7/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Flame supervision

Flame supervision with At mains voltage UN = AC 230 V

ionization probe Detector voltage across terminals 1 and ≤ UN
2 or ground (AC voltmeter Ri ≥ 10 MΩ)
Detector current required for reliable operation min. 3 µA
Possible detector current in operation max. 100 µA

The conductivity and rectifying effect of hot flame gases are used for flame supervision.
For that purpose, AC voltage is applied to the heat-resistant ionization probe which
projects into the flame. The current that flows in the presence of a flame (ionization
current) produces the flame signal which is 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, thereby ensuring that a short-circuit between ionization probe and ground
cannot simulate a flame signal (since in that case AC current would flow).

Basically, the flame supervision circuit is insensitive to adverse effects of the ignition
spark.

However, should the disturbing effects of the ignition spark on the ionization current
exceed a certain level, the electrical connections on the primary side of the ignition
transformer must be changed and / or the location of the ionization probe must be
checked.

Ionization current su- Since the ionization current with burner controls operating on AC 110 V is only about
pervision with burner 50 % of those operating on AC 230 V, certain applications make it necessary to in-
controls operating on crease the ionization current with a transformer.
AC 110 V
Capacity of transformer: Min. 2 VA
Transforming ratio: Approx. 1.1...1.5
The primary and secondary windings of the transformer must be galvanically sepa-
rated.

Connection of AC 115 V
transformer L N

12 2
7435v01/0504

ION
1
LGB2...
AC 115...230 V

8/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Flame supervision with Perm. detector current during the prepurge max. 5 µA
blue-flame detector time (dark current)
QRC1... Detector current required during min. 50 µA
operation
Possible detector current in operation max. 80 µA

Measuring circuit with the QRC1...

7435v02/0601
M LGB3... Legend
- +
sw
1 12 2 M Microammeter Ri max. 5000 Ω
QRC1 sw Black wire
br
br Brown wire
bl
bl Blue wire

The QRC1... has been designed specifically for blue-burning flames. Incidence of light
is from the front and laterally. The flame detector is secured by means of a soft plastic
plug. 3-core connection (preamplifier integrated in the detector casing). For the different
types of flame detectors, engineering notes and technical data, refer to Data Sheet
N7716.

Flame supervision with Mains voltage AC 220 V –15 %...AC 240 V +10 %
UV detector QRA... and Mains frequency 50...60 Hz ±6 %
AGQ... for LGB21... / Power consumption 4.5 VA
LGB22... / LGB41... Degree of protection IP 40
Perm. ambient temperature
- In operation -20...+60 °C
- During transport and storage -40...+70 °C
Perm. length of cable from QRA... to max. 20 m
AGQ1...A27 (use separate cable)
Mounting position optional
Perm. length of connecting cable from max. 20 m
AGQ1...A27 to LGB...
Weight of AGQ1...A27 approx. 140 g

At mains voltage UN:

AC 220 V AC 240 V
Detector voltage at QRA... (with no load)
Up to the end of «t10» and after controlled shutdown DC 400 V DC 400 V
From the beginning of «t1» DC 300 V DC 300 V
Detector voltage
Load by DC measuring instrument Ri > 10 MΩ
Up to the end of «t10» and after controlled shutdown DC 380 V DC 380 V
From the beginning of «t1» DC 280 V DC 280 V
DC detector signals with UV detector QRA... Min. required Max. possible
Measurement on the QRA... 200 µA 500 µA

9/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Flame supervision with UV detector QRA... and auxiliary unit AGQ... for LGB21... / LGB22... / LGB41...

UV detector QRA... Universal flame detector for use with gas and gas / oil burners. Incidence of light from
the front and laterally, total length 97 mm. Available with normal or, as QRA2M, with
higher sensitivity. Secured with flange and clamp. Also available as a metal encapsu-
lated version in the form of the QRA10... (for details, refer to Data Sheet N7712).

Auxiliary unit A special UV auxiliary unit AGQ1...A27 is required in connection with LGB... burner
AGQ1...A27 controls.

That unit is to be connected to the mains supply via 2 cables, and to the burner control
via terminals 1, 2 and 11.

Using circuitry (A) or (B), there are 2 ways to make the quench test on aging UV detec-
tors and to detect UV light:
1. (A) Operation with a permanent line:
UV test at a higher supply voltage across the UV cell on startup and after con-
trolled shutdown.
2. (B) Operation with a controlled line:
UV test at a higher supply voltage only on startup, that is, during the interval
between controlled startup and air pressure signal.
– No voltage at the UV cell after controlled shutdown
– No full substitute for mode (A) above, since an aged UV cell can regenerate
itself

Measuring circuit Connection diagram

7435a15/0704
LGB... LGB...
7435a19/0301

12 2 * 11 1 12 2 * 11 1
(B) (B)

GP/SB
R/W
L
br bl rt sw br bl rt sw
AGQ1...A27
sw bl AGQ1...A27 L (A) sw bl
N
QRA

+
QRA
-

Measurement made on the flame detector

Legend GP Gas pressure switch

R Temperature or pressure controller
SB Safety limit thermostat
W Limit thermostat or pressure switch
* With LGB41...: Terminal 3
(A) Operation with permanent line
(B) Operation with controlled line

10/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Functions
The function diagrams show the required or permissible input signals to the control
section and to the flame supervision circuit hatched (refer to «Connection diagrams»).
If these input signals are not present, the burner control will stop the startup sequence to
trigger lockout where required by safety regulations.

Preconditions for - Burner control must be reset

burner startup - The contacts of gas pressure switch «GP», limit thermostat / pressure switch «W»,
control thermostat / pressurestat «R» and safety limit thermostat «SB» must be
closed
- Fan motor «M» or AGK25 must be connected
- Air pressure switch «LP» must be in its no load position

Undervoltages LGB... burner controls are capable of detecting undervoltages. This means that load
relay «AR» will be deenergized if mains voltage drops below AC 160 V (for nominal AC
220...240 V) or AC 75 V (for nominal AC 100...110 V).
The burner control will automatically make a restart attempt when the supply voltage
returns to a level above AC 160 V and AC 75 V respectively.

Reversed polarity If the connections of live conductor (terminal 12) and neutral conductor (terminal 2) are
protection mixed up, the burner control will initiate lockout at the end of «TSA».

Startup sequence A–C Startup sequence

A Start command (switching on)

This command is triggered by control thermostat / pressurestat «R».
Terminal 12 receives voltage and the programming mechanism starts running.
On completion of waiting time «tw» with the LGB21..., or after air damper
«SA» has reached the nominal load position (on completion of «t11») with the
LGB22... / LGB32..., fan motor «M» will be started.

TSA Ignition safety time

On completion of «TSA», a flame signal must be present at terminal 1.
That flame signal must be continuously available until shutdown occurs, or
else flame relay «FR» will be deenergized, resulting in lockout.

tw Waiting time
During the waiting time, air pressure switch «LP» and flame relay «FR» are
tested for correct contact positions.

t1 Prepurge time
Purging the combustion chamber and the secondary heating surfaces:
Required with low-fire air volumes when using the LGB21... and with nominal
load air volumes when using the LGB22... / LGB32...
«Type summary» and the «Function and sequence diagrams» show the so-
called prepurge time «t1» during which air pressure switch «LP» must indi-
cate that the required air pressure is available.
The effective prepurge time «t1» comprises interval end «tw» through «t3».

t3 Preignition time
During «t3» and up to the end of «TSA», flame relay «FR» is forced to close.
On completion of «t3», the release of fuel is triggered at terminal 4 or at termi-
nal 11 of the LGB41...

11/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
 t3n Postignition time
Ignition time during «TSA»
Just before reaching the end of «TSA», ignition transformer «Z» will be
switched off.
This means that «t3n» is somewhat shorter than «TSA».
This is necessary in order to give the forcedly closed flame relay «FR» suffi-
cient time to drop out if there is no flame.

t4 Interval
LGB21... / LGB41...: Time to the release of the second fuel valve «BV2»
LGB22... / LGB32...: On completion of «t4», the heat source is controlled
depending on the load (release of load controller «LR»)

t9 Second safety time

(Only with LGB41...)
For pilot burners with main flame supervision equipped with a pilot gas valve
«ZV1».

t10 Specified time for air pressure signal

On completion of this period of time, the set air pressure must have built up, or
else lockout will occur.

t11 Programmed opening time for actuator «SA»

(Only with LGB22... / LGB32...)
The air damper opens until the nominal load position is reached. Only then will
fan motor «M» be switched on.

t12 Programmed closing time for actuator «SA»

(Only with LGB22... / LGB32...)
During «t12», the air damper travels to the low-fire position.

B – B´ Interval for establishment of flame

C Burner operating position reached

C–D Burner operation (generation of heat)

Nominal output or, in connection with a load controller «LR», part load opera-
tion.

D Shutdown by «R»
The burner is immediately shut down and the programming mechanism is
ready for a new start.

12/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Control sequence in In principle, whenever lockout occurs, the fuel supply will immediately be shut down. If
the event of fault that takes place between startup and preignition, which is not indicated by a symbol,
the usual cause is air pressure switch «LP» shutting down, or a premature, faulty flame
signal.

• After a mains failure or in the event of un- New startup with full program sequence
dervoltage: on power restoration
• Premature flame signal from the start of «t1»: Immediate lockout
• Contacts of air pressure switch «LP» have Prevention of startup
welded during «tw»:
• No air pressure signal: Lockout on completion of «t10»
• Air pressure failure on completion of «t10»: Immediate lockout
• Burner does not ignite: Lockout on completion of «TSA»
• Flame is lost during operation: Immediate lockout

Lockout After lockout, the LGB... will remain locked (lockout cannot be changed).
This state will also be maintained in the event of mains voltage failure.

Resetting the LGB... Whenever lockout occurs, the burner control can immediately be reset.

Lockout and control sequence indication

The position of the programming mechanism can be seen through the viewing window
on the front of the unit. In the event of fault, the programming mechanism stops and
thus the lockout indicator also. The symbol in the viewing window indicates both the
position in the control sequence and the type of fault according to the following legend:

 No startup since the start control loop is open

Interval «tw» or «t10» (LGB21...)

IIII Interval «tw» or «t11» (LGB22... / LGB32...)
Interval «tw», «t3» or «TSA» (LGB41...)

 Air damper fully open (LGB22... / LGB32...)

Lockout due to absence of air pressure signal

P
ÍÍÍ Interval «t1», «t3» and «TSA» (LGB21...)
Interval «t1», «t3» («t12») (LGB22... / LGB32...)

 Release of fuel

Lockout since there is no flame signal on completion of the first safety time
1
Release of second fuel valve (LGB21... / LGB41...)
2 Release of load controller (LGB22... / LGB32...)

Lockout since there is no flame signal on completion of the second safety time
3 (LGB41...)

zzzz Partial load or nominal load operation (or return to the operating position)

13/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Connection diagrams
LGB21... Flame supervision

Burner controls for 1- or 2-stage forced draft burners. LGB21...: With ionization probe or auxiliary unit AGQ1...A27 for UV detector
Air damper control for prepurging with low-fire air volume. QRA...

A B B´ C D
GP/SB 12 2 10 8 3 6 11 7 9 4 5 1
R/W 12
tw t1
GP/SB bv1 Dbr1 ION
M 3
t10 bv2
6
LP W
t3 11
AL M Z BV1 BV2
LP
Z 7
R EK2

BV1 4 HS
t4

7435a09/0704
BV2 5 0 I

Si
TSA L
FS 1 N
7435f01/1299

LGB2... LKP
Application examples t1
LR NL I
Control of actuators of 2-stage or 2-stage modulating burners.
SA RV
Prepurging («t1») with low-fire air volume. IV IV
BV1 KL IV
Same low-fire actuator position (switching cam III) during startup and III III
Zu t
operation!
II

For information about actuators «SA»:

SQN3...: Refer to Data Sheet N7808
SQN7...: Refer to Data Sheet N7804
SQN9...: Refer to Data Sheet N7806

12 2 10 8 3 6 11 9 7 4 5 1 12 2 10 8 3 6 11 9 7 4 5 1
(*)
Dbr1 ION Dbr1 ION
EK2 EK2 LP
LP
AL M Z M Z
AL
BV1 BV1
GP GP

R/W LR R/W LR

(*) BV2 BV2

SB * SB
N 1 2 6 7 5 4 3 N N 1 2 5 3 6 4
HS B HS
b1 b2
7435a01/0704

K2
0 I 0 I
Si
Si

III IV +
IV III
N L a b a b N L
A a b D a b

a3 a2 a1 RV - +
K1
C3
II I V C31
MS II I V
a b a b a b MS
SA LK a b a b R32 R1 a b
LK
SA
7435a02/0704
SQN3...121...
SQN91.140... / 2-stage control
* Note:
With 2-stage modulating burners (with gas control damper «RV»),
«BV2» and the dotted connection between terminals (*) are not
required

14/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Connection diagrams (cont’d)
LGB21...

12 2 10 8 3 6 11 9 7 4 5 1

LP
ION
Z
EK2

AL M GP BV1

R/W LR

BV2

SB
HS
N 8 4 1 5 3 2 7 6
0 I LKP
Si

b2 NL I I
N L a1 c1 IV IV
KL III III

b1 a2 Zu II
t1 TSA t
t4
B A C
7435a03/0704

M
I II III IV

SQN7...244 / 2-stage control

Burner without fan and without «LP» QRA... with auxiliary unit AGQ1... with LGB21... (diagram 7435a06)

2 3 11 6 12 2 11 1

AGK25
GP/SB
7435a04/0398 R/W
L br bl rt sw
L AGQ1 sw bl
Burner with fan control via auxiliary contactor («HS») with «LP» N
7435a06/0704

+
QRA
12 2 3 11 6 -

Legend
GP/SB HS AGK25 LP
R/W bl Blue wire
M
L br Brown wire
N
7435a16/1299 rt Red wire
sw Black wire

15/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Connection diagrams (cont’d)

LGB22... / LGB32... Flame supervision

Burner controls for single- or 2-stage forced draft burners. LGB22...: With ionization probe or auxiliary unit AGQ1... for UV detector
Air damper control for prepurging with nominal load air volume. QRA...
LGB32...: With blue-flame detector QRC1...

A B B´ C D Nur LGB22...
GP/SB LGB22... / LGB32...
R/W 12 1
12 2 10 8 3 6 11 9 5 7 4
3 ION
GP/ LR
Nocke I SB LP
LK
W Nur LGB32...
M
tw t11 t10 t1 t12 2 8 3 1 1
6 R
LP 7 10 sw
t3 11 HS 6 SA br
QRC1... 12
Z 7 0 I AL Z BV1 bl
M

Si
L EK2 2
BV1 4
t4 N
7435a10/0704
LR 5
TSA LGB22.../32... LKP
FS 1 t1
LR NL
9 SA I
7435f02/0700
BV1/2 KL
Zu III III
Application examples t
II
Control of actuators of 2-stage or 2-stage modulating burners.
Prepurging («t1») with nominal load air volume.

For information about the actuators:

SQN3...: Refer to Data Sheet N7808
SQN7...: Refer to Data Sheet N7804
SQN9...: Refer to Data Sheet N7806

LGB22... LGB22...

12 2 10 8 3 6 11 9 5 7 4 1 12 2 10 8 3 6 11 9 5 7 4 1

ION GP ION
EK2 Z EK2 LP
GP LP
AL LR Z
AL
S1) W BV1
R/W M BV1
LR
R M

* SB
7435a08/0704

BV2 *
HS 6 8 10 2 1 3 7 9
SB
N 1 8 2 7 5 6 3 4 9 2) R3
HS
0 I R1
Si

R3
R1

0 I K2
7435a20/0704

N L
Si

B b1 b2
K1
N L
A a1 a2

C3 III RV

M LK
R2 I II
I II III V 1)
5 MS
RV C1
2
LK
SQN3...151... or SQN3...251... SA

* Note: SQN90.220... / 2-stage modulating control

With 2-stage modulating burners (with gas control damper «RV»),
«BV2» and the dotted connection between terminals marked (*) are not
required.

16/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Connection diagrams (cont’d)
LGB22... / LGB32...

LGB22... LGB22...

12 2 10 8 3 6 11 5 9 7 4 1 12 2 10 8 3 6 11 9 5 7 4 1

R/W LP R/W LP
Z ION Z ION
EK2 EK2
LR LR
GP AL M GP
AL M 1 2
BV1 BV1

BV2 BV2
SB
SB
HS N 5 4 1 3 2 8 6 7 HS N 4 5 1 3 2 8 6 7

0 I b2 0 I
Si

b2

Si
a1 c1
N L a1
LKP N L
NL I I

IV IV b1 a2
b1 a2
KL III III
7435a17/0704

A B
C A B
M Zu II
M
I II III IV t1 TSA t
5 I II III IV
t4 2

SQN7...454 / 2-stage control SQN7...424 / 2-stage control

Single-wire control 2-wire control

Burner without fan and without «LP» QRA... with auxiliary unit AGQ1... with LGB22... (diagram 7435a06)

12 2 11 1
LGB22... / LGB32...

GP/SB
2 3 11 6 R/W
L br bl rt sw
AGK25 L AGQ1 sw bl
7435a04/0398
N
7435a06/0704

+
QRA
-

Burner with fan control via auxiliary contactor («HS») with «LP» Legend
bl Blue wire
LGB22... / LGB32... br Brown wire
rt Red wire
12 2 3 11 6
sw Black wire
GP/SB HS AGK25 LP
R/W
M
L
N
7435a16/1299

Legend

TSA Ignition safety time

t1 Prepurge time
t4 Interval «BV1 – BV2»
LGB22... / LGB32...: interval «BV1 - LR»

AL Alarm LR Load controller

BV... Fuel valve M Fan motor
EK2 Remote reset button NL Nominal load
ION Ionization probe R Control thermostat or pressurestat
GP Gas pressure switch SB Safety limit thermostat
HS Mains isolator Si Primary fuse
KL Low-fire W Limit thermostat
LKP Air damper position Z Ignition transformer
LP Air pressure switch

17/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Connection diagrams (cont’d)
LGB41...

Burner controls for atmospheric gas burners with or without fan. No actuator control. Flame supervision with ionization probe

A tw B B´ C D
GP/SB
12
R/W t3
Z 7
TSA
BV1 4
t4
ZV1 11
t9
BV2 5

FS 1
7435f03/0301
QRA... with auxiliary unit AGQ1... with LGB4... (Pictures
7435a21)
12 2 10 8 3 6 11 7 9 4 5 1
Dbr2
GP/ 12 2 3 1
bv1 Dbr1 ION
SB zv1

W bv2 GP/SB
R/W
AL Z BV2
M L br bl rt sw
R EK2 L AGQ1 sw
ZV1 BV1 bl
N
HS 7435a21/0704

+
0
QRA
-
Si

L
N
7435a11/0704

ION
ION2 ION1

ZR
7435s01/0504

7435s02/0504

HR HR
BV1 BV2 BV2 ZV1

Legend
A Startup (switching on by «R») AL Alarm
B – B´ Interval for establishment of flame BV... Fuel valve
C Operation position of burner or release of the second stage bv... Auxiliary switch in the fuel valves (for control the closed position)
by load controller «LR» Dbr1 Wire link
D Shutdown by «R» Dbr2 Wire link, required when contacts «bv» or «zv1» is missing
EK2 Remote reset button
tw Waiting time ION Ionization probe
TSA Ignition safety time FS Flame signal
t3 Preignition time GP Gas pressure switch
t4 Interval «BV1 – BV2» HR Main ramp
t9 2. safety time HS Main switch
M (Auxiliary) fan motor
QRA... UV flame detector
QRC... Blue flame detector
bl Blue wire
br Brown wire
Required input signals rt Red wire
Burner control’s output signals sw Black wire
R Control thermostat or pressurestat
SB Safety limit thermostat
Si Primary fuse
W Limit thermostat
• Connection of valves with pilot burners with main flame Z Ignition transformer
supervision ZR Ignition ramp
•• Connection of valves with 2-stage atmospheric burners ZV1 Ignition gas valve
with supervision of the first stage («BV1») zv1 Auxiliary switch in ignition gas valve

18/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Internal diagram and time diagram of the programming mechanisms
LGB21...

L N
HS Legend
GP/ W
a SB R
br 12 0 I
AL Alarm
b
AS AR Load relay with contact «ar»
1)
M
3 AS Unit fuse
I ar BR Locking relay with contact «br»
a ba b
LP BV... Fuel valve
Dbr1 Wire link
6 11
a b EK... Lockout reset button
IV
FR Flame relay
FR
fr GP Gas pressure switch
a b
AR HS Mains isolator
V VI IX VII
a b a a b b a ION Ionization probe
a b a b L1 Lockout warning lamp
II VIII
LP Air pressure switch
BR

MS M Fan motor
EK1 MS Synchronous motor
L1

7435i01/0504
R Control thermostat or pressurestat
2 10 8 4 5 7 9 1 SB Safety limit thermostat

BV2 ION W Limit thermostat or pressure switch

AL EK2
BV1 Dbr1
Z Z Ignition transformer

A Start position (switching on)

A B C
B Operating position of burner
b
I a C Operating position of programming mechanism or start
position
7435f04/0801

II b
a
tw t10 t1
I...IX Cam switches

b tw Waiting time
IV a
t3 TSA t4 t20 TSA Ignition safety time
b
V a T Total running time of programming mechanism
t1 Prepurge time
b 4
VI a t3 Preignition time
t4 Interval «BV1 – BV2»
b 7
VII a t10 Specified time for air pressure signal
b t20 Interval up to self-shutdown of programming
VIII a
mechanism
b
IX a 5
1) Resistance between terminal 3 and «N» must not
b
AR a 3 exceed 1.6 kΩ
2) Only with LGB21.130A27
b
FR a
T = 81 s (40,5 s 2) )

19/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Internal diagram and time diagram of the programming mechanisms (cont’d)

LGB22... / LGB32...

L N
HS Legend
GP/ W R
a br
12 SB 0 I
b
AL Alarm
AS M AR Load relay with contact «ar»
1)
3
I ar AS Unit fuse
a b a b BR Locking relay with contact «br»
LP
BV... Fuel valve

7435i02/0704
6 11
III a b EK... Lockout reset button
b IV
a FR Flame relay

FR
fr
GP Gas pressure switch
a b
AR V VII HS Mains isolator
VI IX
b a
b a a b b a ION Ionization probe
a b a b
II VIII L1 Lockout warning lamp
BR

LP Air pressure switch

MS
M Fan motor
EK1 L1
MS Synchronous motor

2 10 8 9 4 5 7 1
R Control thermostat or pressurestat
SB Safety limit thermostat
AL EK2 BV1 Z
BV2 W Limit thermostat or pressure switch
Z Ignition transformer
Nur LGB22... Nur LGB32...

1 1
sw
ION br
QRC1... 12
bl
2

A B C
A Start position (switching on)
b
I a B Operating position of burner
C Operating position of programming mechanism or start
7435f05/1299

b
II a
position
b
III a
tw t11 + t10 t1 t12 I...IX Cam switches
b
IV a 9
tw Waiting time
b
V a
TSA Ignition safety time
b T Total running time of programming mechanism
VI a 4
t3 TSA t4 t20 t1 Prepurge time
b
VII a 7 t3 Preignition time
t4 Interval «BV1 – BV2» or «BV1 – LR»
b
VIII a t10 Specified time for air pressure signal
t11 Programmed opening time for actuator «SA»
b
IX a 5
t12 Programmed closing time for actuator «SA»
b t20 Interval up to self-shutdown of programming
AR a 3
mechanism
b
FR a
T = 81 s 1) Resistance between terminal 3 and «N» must not ex-
ceed 1.6 kΩ

20/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Internal diagram and time diagram of the programming mechanisms (cont’d)

LGB41...

L N
HS Legend
GP/ W R
a br
12 SB 0 I
AL Alarm
b
AS AR Load relay with contact «ar»
AS Unit fuse
I ar
a b a b BR Locking relay with contact «br»
1) M
3 BV... Fuel valve
b Dbr1 Wire link
a
III Dbr2 Wire link terminal 6-2 required when contact «bv» or «zv1»
FR is missing
fr
a b EK... Lockout reset button
AR IX VII
V VI FR Flame relay
a a b b
b a
a b a GP Gas pressure switch
II VIII b HR Main burner
BR

MS HS Mains isolator
L1 ION Ionization probe

7435i03/0504
IV
EK1 L1 Lockout warning lamp
a
2 10 8 6 11 4 5 7 9 1 M Fan motor
MS Synchronous motor
Dbr1
Dbr2

AL ZV1 BV1 BV2 Z R Control thermostat or pressurestat

EK2 ION
SB Safety limit thermostat
W Limit thermostat or pressure switch
A B C
Z Ignition transformer
Ib
a ZR Pilot burner
ZV1 Pilot gas valve in place of «BV1» in the case of pilot
II b
a
burners with main flame supervision
III b
a 6
t9
tw Waiting time
IV b
a 11
TSA Ignition safety time
tw t3 TSA t4 t20
T Total running time of programming mechanism
Vb
a
t3 Preignition time
VI b
a 4 t4 Interval «BV1 – BV2»
t9 Second safety time
VII b
a 7
t20 Interval up to self-shutdown of the programming
mechanism
VIII b
a

IX b
a 5 A Start position ( switching on)
B Operating position of burner
AR b
7435f06/0301

a C Operating position of programming mechanism or start

position
FR b
a
T = 40,5 s
I...IX Cam switches
ION
ION2 ION1
1) Resistance between terminal 3 and «N» must not exceed
1.6 kΩ
ZR
7435s01/0504

7435s02/0504

HR HR
BV1 BV2 BV2 ZV1

21/22

Building Technologies CC1N7435en

HVAC Products 11.01.2007
Dimensions
Dimensions in mm

22
LGB...

5,5
62,5

7435m06/1106
9
Plug-in base
AGK11... / AGK13... 88 41,5
91

47

62,5

Auxiliary unit
Type Dimension
27,5

AGQ1...A27
reference A B
AGQ1.1A27 500 19

90,5 AGQ1.2A27 300 34

60

220 69 6
65,6
4
18

5,4 5,4

B 6
13 7435m01/0301
A

©2007 Siemens Building Technologies HVAC Products GmbH

22/22 Subject to change!

Building Technologies CC1N7435en

HVAC Products 11.01.2007