Elster BCU 480 User manual

6.1.2.8 Edition 06.07
Technical Information · GB
www.kromschroeder.com
For pilot and main burners of unlimited capacity in intermittent or continuous•
operation pursuant to EN 746-2
Automatic burner control unit, ignition transformer, indicators and operating•
controls in a space-saving metal housing which replaces the local burner
control cabinet
Flame control by UV, ionisation or a further option of using the furnace•
chamber temperature
Display of the program status, unit parameters and flame signal; Manual•
mode for burner adjustment and for diagnostic purposes
Visualisation and adaptation to the specific application via the PC•
programming and diagnostic software BCSoft to simplify logistics
management
Spacious connection chamber with plug-in terminal blocks and plug-in cable•
glands for quick installation and servicing
Air valve control relieves the furnace control•
Optional PROFIBUS-DP interface•
EC type-tested and certified•
Burner control units BCU 480

BCU 480 · Edition 06.07
2
t= To be continued
Contents
Burner control units BCU 480 ....................... 1
Contents........................................2
1 Application.....................................4
2 Examples of application ..........................6
2.1 Stage-controlled main burner with alternating
pilot burner ......................................6
2.2 Stage-controlled main burner with permanent
pilot burner ......................................7
2.3 Two-stage-controlled main burner with permanent
pilot burner ......................................8
2.4 Modulating-controlled burner ....................9
2.5 BCU 480..B1 for PROFIBUS-DP ...................10
2.6 BCU 480..D:High temperature equipment .........10
3 Certification ....................................11
3.1 EC type-tested and certified ......................11
3.2 AGA .........................................11
3.3 FM ..........................................11
3.4 Profibus User Organisation ......................11
4 Function...................................... 12
4.1 Connection diagrams ..........................12
4.1.1 BCU 480.........................................12
4.1.2 BCU 480..B1 with Profibus ..........................13
4.1.3 BCU 480..P with 16-pin industrial plug connector .......14
4.2 BCU 480 program sequence ....................16
4.3 Program status and fault messages ..............19
5 Parameters ...................................20
5.1 Scanning the parameters . . . . . . . . . . . . . . . . . . . . . . . 21
5.2 Flame control.................................22
5.2.1 Flame signal, pilot burner ......................... 22
5.2.2 Flame signal, main burner ........................ 22
5.2.3 Program status when the most recent fault occurred .. 22
5.2.4 Switch-off threshold of the flame amplifier ........... 22
5.2.5 High temperature operation in the case of BCU..D2 or
BCU..D3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.2.6 UVS check...................................... 26
5.3 Pilot and main burner monitoring ................27
5.3.1 Permanent pilot burner ........................... 28
5.3.2 Interrupted pilot burner ........................... 28
5.4 Behaviour in start-up position/standby............29
5.4.1 Flame simulation check in start-up position/standby ... 29
5.4.2 Minimum burner pause time tBP ................... 30
5.5 Behaviour during start-up ......................31
5.5.1 Safety time on start-up tSA ..........................31
5.5.2 Flame proving period tFS ......................... 32
5.5.3 Minimum combustion time tB..................... 32
5.5.4 Burner start-up attempts.......................... 33
5.6 Behaviour during operation .....................35
5.6.1 Safety time during operation tSB for pilot and
main burners........................................ 35
5.6.2 Fault lock-out or restart, pilot burner ................ 35
5.6.3 Immediate fault lock-out following flame failure....... 35
5.6.4 Fault lock-out or restart, main burner.................37
5.7 Air valve control on BCU..L ......................39
5.7.1 Purge .......................................... 39
5.7.2 Cooling in start-up position/standby ................ 39
5.7.3 Burner start..................................... 39
5.7.4 Air valve opens in the case of external activation
(not during start-up) .................................. 40
5.7.5 Air valve opens in the case of external activation
(even during start-up) ..................................41
5.7.6 Air valve opens with valve V2 ...................... 42
5.7.7 Air valve opens with operating signal ............... 43
5.7.8 Low fire over run time tKN after a normal shut-down ... 44
5.7.9 Behaviour of the air valve in the event of a
fault lock-out ........................................ 45
5.8 Manual mode ................................46
5.8.1 Manual mode limited to 5 minutes.................. 46

BCU 480 · Edition 06.07
3
t= To be continued
6 Selection .....................................47
6.1 Safety time ...................................47
6.1.1 Calculating the safety time tSA .......................47
6.2 Selection table................................48
7 Project planning information......................49
7.2.1 Cable selection .................................. 49
7.2.2 Ignition cable ................................... 49
7.2.3 Ionisation cable ................................. 49
7.2.4 UV cable ....................................... 49
7.1 Ignition electrode ..............................49
7.1.1 Electrode gap.................................... 49
7.1.2 Star electrodes .................................. 49
7.2 Minimum combustion time......................50
7.3 Safety interlocks (Limits).........................50
7.4 Emergency stop ...............................50
7.4.1 In the event of fire or electric shock .................. 50
7.4.2 Via the safety interlocks (limits) ..................... 50
7.5 Reset........................................51
7.5.1 Parallel reset .....................................51
7.5.2 Permanent remote reset ...........................51
7.5.3 Automatic remote reset (PLC) .......................51
7.5.4 Burner start ......................................51
7.5.5 Restart and start-up attempts .......................51
7.6 Fault signalling................................52
7.7 Protecting the pilot burner from overload ..........52
7.8 Installation ...................................53
7.9 Wiring .......................................53
7.10 BCU switched off .............................55
7.11 Furnace control ...............................55
7.12 Mains switch ................................55
7.13 Note on EC type-examination ...................55
7.14 Changing parameters .........................56
8 Flame control .................................57
8.1 With ionisation sensor ..........................57
8.2 With UV sensor ...............................57
8.3 Via the temperature in high temperature
equipment ......................................57
9 Accessories ...................................58
9.1 High-voltage cable ............................58
9.2 16-pin industrial plug connector .................58
9.3 BCSoft.......................................58
9.4 “Changed parameters” stickers..................58
9.5 External securing bar ..........................59
9.6 Fastening set .................................59
9.7 Radio interference suppressed electrode adapters..59
10 Technical data ................................60
10.1 Housing dimensions ..........................62
10.2 Operating controls............................62
11 Legend ......................................63
12 Glossary.....................................64
12.1 Waiting time tW..............................64
12.2 Safety time on start-up tSA .....................64
12.3 Ignition time tZ...............................64
12.4 Flame simulation/Flame simulation delay time tLV ..64
12.5 Safety time during operation tSB ................64
12.6 Flame signal.................................65
12.7 Fault lock-out ................................65
12.8 Safety interlocks (Limits) ........................65
12.9 Pilot gas valve V1 .............................65
12.10 Main gas valve V2 ...........................65
12.11 Continuous operation.........................65
12.12 Air valve ...................................65
Feedback ......................................66
Contact........................................66

BCU 480 · Edition 06.07
4
Application1
The burner control units BCU 480 control, ignite and monitor
gas burners for intermittent or continuous operation. As a re-
sult of their fully electronic design they react quickly to various
process requirements and are therefore suitable for frequent
cycling operation.
They can be used for industrial burners of unlimited capacity
which are ignited by pilot burners. Pilot and main burners may
be modulating or stage-controlled. The BCU 480 monitors pilot
and main burners independently. The pilot burner can burn
permanently or be switched off. The BCU is installed near to
the burner to be monitored.
On industrial furnaces, the BCU reduces the load on the cen-
tral furnace control by taking over tasks that only relate to the
burner, for example it ensures that the burner always ignites
in a safe condition when it is restarted.
The air valve control assists the furnace control for cooling,
purging and capacity control tasks.
The program status, the unit parameters and the level of the
flame signal can be read directly from the unit. The burner
can be controlled manually for commissioning and diagnostic
purposes.
If the local requirements on the burner control unit change, the
PC software “BCSoft” can be adjusted to the unit parameters
of the application by using the optical interface.
The service personnel is supported by a convenient visuali-
sation system of the input and output signals and the error
history.
The BCU unites the
functionally interre-
lated components
of automatic burner
control unit, igni-
tion transformer,
Manual/Automatic
mode and display
of operating and
fault statuses in
a compact metal
housing.
t

BCU 480 · Edition 06.07
5
To reduce the installation and wiring costs, Elster Kromschröder
offers an optional PROFIBUS-DP interface to transfer the ac-
tivation signals and feedbacks so as to expand the remote
servicing and diagnostics facilities.
Bogie hearth forg-
ing furnace in the
metallurgical in-
dustry
Intermittent shuttle
kiln in the ceramics
industry
Walking beam
furnace with over-
head firing
Application

BCU 480 · Edition 06.07
6
BCU 480
14 12
23
26
SPS
PLC
API
DI
L1, N, PE
P
22 4 21 18
19
16
17
28
29
24
2
1
t
1
2
A
P
5
3
DI
6
02–0402–04 06–08 06–08
ϑ 2
ϑ 1
ϑ 1
ϑ 2
µC
VR..L
VAG
UV
VBY
2
1
Examples of application2
Stage-controlled main burner2.1
with alternating pilot burner
Control:
Main burner ON/OFF.
The main burner can be started with re-
duced capacity after the operating signal
from the pilot burner has been detected.
The pilot burner is switched off automati-
cally after the main burner has started
up. When the main burner is switched off,
the pilot burner automatically switches
on again. This reduces the main burner
start-up time.
A UV sensor monitors the flame signal
from pilot and main burners. UV sensor
UVD 1 is used for continuous operation,
UV sensor UVS for intermittent opera-
tion.
The BCU provides the cooling and purg-
ing processes.

BCU 480 · Edition 06.07
7
t
1
2
BCU 480
14 12
23
26
SPS
PLC
API
DI
L1, N, PE
P
22 4 21 18
19
16
17
28
29
24
2
1
A
P
5
3
DI
6
0402–04 06–08 06–08 04
µC
ϑ 1 ϑ 2
ϑ 1
ϑ 2
VR..R
VAG
VBY
2
1
Stage-controlled main burner 2.2
with permanent pilot burner
Control:
Main burner ON/OFF.
The main burner can be started with
reduced capacity after the operating
signal from the pilot burner has been
detected. Pilot and main burners can be
operated simultaneously. This reduces
the time required by the main burner
for starting up.
The BCU provides the cooling and purg-
ing processes.
Examples of application

BCU 480 · Edition 06.07
8
BCU 480
12
23
SPS
PLC
API
DI
L1, N, PE
P
22 4 21 18
19
16
17
28
29
24
2
1
A
P
5
3
DI
6
VBY
µC
ϑ 1 ϑ 2
t
1
2
0402–04 06–08 06–08 04
ϑ 1
ϑ 2
2
1
BV
IC 40
4
7
M
14
26
50 51
VAG
VAS
Two-stage-controlled main2.3
burner with permanent pilot
burner
Control:
Main burner ON/OFF with ignition via
bypass.
The main burner can be started at low-
fire rate after the operating signal from
the pilot burner has been detected. When
the operating state is reached, the BCU
issues the Enable signal for the maxi-
mum burner capacity. Pilot and main
burners can be operated simultaneously.
This reduces the time required by the
main burner for starting up.
The BCU provides the cooling and purg-
ing processes.
Examples of application

BCU 480 · Edition 06.07
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BCU 480
14 12
SPS
PLC
API
DI
L1, N, PE
4 21 18
19
16
17
28
29
24
2
1
P
5
3
DI
6
mA
µC
ϑ 1
ϑ 2
VAG
VBY
BV+IC
M
2
1
Modulating-controlled burner 2.4
Control:
Main burner continuous
The butterfly valve for air is moved to ig-
nition position in order to start the main
burner. The main burner can be started
at low-fire rate after the operating signal
from the pilot burner has been detected.
The control system controls the burner
capacity via the butterfly valve for air
after the operating state has been sig-
nalled. Pilot and main burners can be
operated simultaneously. This reduces
the time required by the main burner
for starting up.
Examples of application

BCU 480 · Edition 06.07
10
PROFIBUS-DP
BCU 480..B
BUS
1–6
BCU 480..B
BUS
BCU 480..B
BUS
1–61–6
SPS
PLC
API
DI
L1, N, PE
P
BUS
STW
L1
DI
BCU 480..D
DI
>750 °C
6
924
BCU 480..D
6
924
µC µC
BCU 480..B1 for PROFIBUS-DP2.5
The bus system transfers the control
signals for starting, resetting and for
controlling the air valve from the control
system to the BCU 480..B1. In the oppo-
site direction it sends operating status,
the level of the flame signals and the
current program status.
Control signals that are relevant for safety,
such as the safety interlocks, purge (op-
tional) and digital input, are transferred
independently of the bus communication
by separate cables.
BCU 480..D:2.6
High temperature equipment
Indirect flame control using the tempera-
ture. During the start-up process, as long
as the wall temperature is below auto
ignition temperature the flame must be
controlled by conventional methods.
When the working temperature has ex-
ceeded 750°C, the safety temperature
monitor (STW) takes over the indirect
flame control.
Examples of application

BCU 480 · Edition 06.07
11
Certification3
The burner control unit BCU 480 is designed for applications
pursuant to the Machinery Directive (98/37/EC).
EC type-tested and certified3.1
pursuant to
– Gas Appliances Directive (90/396/EC) in conjunction with
EN 298
– Low Voltage Directive (73/23/EEC) in conjunction with EN
60730
– Electromagnetic Compatibility Directive (89/336/EEC)
AGA3.2
Certified under No. 6478
FM3.3
BCU..T is FM approved.
Standard: Factory Mutual Research Standard 7610:
June 1997
Suitable for applications pursuant to NFPA 86
Profibus User Organisation3.4
BCU..B1
PUO = PROFIBUS User Organisation,
Certificate No. Z 00692 pursuant to EN 50170-1, -3

BCU 480 · Edition 06.07
12
L1 (L1)
N (L2)
PE
1 2 PE
N N
s
s1
V1 V2 C N S M L
µC
l
N
v1
c2
88
c1 N
v2
BCU 480
V1 V2
O
I
F1 F2
230V~
max. 2 A,
253 V
I
Z
30 31 32 33 34 35 36 37
DI
50 51
l
38
F3
(BCU 480..C)
40 41 42 43 44 45 46 47
UVS 1
2
3
P
5 6 7 8 119 10 12 13 14 15 25 26 2718 19 20 22 24
PE 7 8 9 10 24 25PE 7 8 9 24
A
23
ϑ
3 4
1 ϑ
2
21
Function4
Connection diagrams4.1
For cable selection and wiring, see Project planning informa-
tion.
BCU 4804.1.1
For the explanation of symbols, see Legend.

BCU 480 · Edition 06.07
13
L1 (L1)
N (L2)
PE
1 2 PE
N N
s
s1
V1 V2 C N S M L
µC
l
N
v1
c2
88
c1 N
v2
BCU 480..B1
V1 V2
O
I
F1 F2
230V~
max. 2 A,
253 V
I
Z
30 31 32 33 34 35 36 37
DI
50 51
l
38
BCU 480..B1/1
PROFIBUS-DP
2B 2A 1B 1A
OFF
ON
F3
(BCU 480..C..B1)
40 41 42 43 44 45 46 47
UVS 1
2
3
P
56 78119 10 12 13 14 15 25 26 2718 19 20 22 24
PE 7 8 9 10 24 25PE 7 8 9 24
OFF
ON
BCU 480..B1 with Profibus4.1.2
For the explanation of symbols, see Legend.
For further information on BCUs with Profibus, see Technical
Information Bulletin “Burner control unit for Profibus-DP BCU
400..B1”.
Function > Connection diagrams

BCU 480 · Edition 06.07
14
BCU 480..P with 16-pin industrial plug connector4.1.3
The burner control unit BCU 480..P can be supplied with an
industrial chassis plug (pursuant to VDE 0627). This 16-pin
plug connector ensures fast connecting or disconnecting of
units without any additional wiring required. This simplifies
replacing units and reduces standstill times.
All signals to the higher-level control system, the mains supply
and the safety interlocks are routed via this plug.
See “Accessories”.
Function > Connection diagrams

BCU 480 · Edition 06.07
15
1
1 2 PE
N N
s
s1
V1 V2 C N S M L
µC
l
N
v1
c2
88
c1 N
v2
BCU 480..P
V1 V2
O
I
F1 F2
230V~
max. 2 A,
253 V
I
Z
30 31 32 33 34 35 36 37 50 51
l
38
F3
(BCU 480..P..C)
40 41 42 43 44 45 46 47
UVS 1
2
3
56 78119 10 12 13 14 15 25 26 27
18 19 20 22 24
PE 7 8 9 10 24 25PE 7 8 9 24
23
34
2
DI
16 15 14 12 11 10 9
87654321
P A
L1 (L1)
N (L2)
PE
16 15 14 87 12 511 10 439 2 16
2
1
21
1716 28 29
ϑ1ϑ2
BCU 480..P with industrial plug connector
For the explanation of symbols, see Legend.
Function > Connection diagrams

BCU 480 · Edition 06.07
16
01
01
02
03
04
08
00
00
08
05
06
07
Switch on BCU 480
Pilot burner start-up
with ϑ1 signal
Safety interlocks (Limits)
In the event of fault signal:
reset
If parameter P15 = 1:
flame simulation check
Wait until
min. burner pause time tW
has elapsed
If parameter P15 = 0:
flame simulation check
If no flame detected:
max. 4 start-up attempts
or fault lock-out
Start-up position/standby
Safety time tSA1
running (P22),
ignition in process,
V1 opens and min.
combustion time tB
starts to elapse (P20)
In the event of flame failure:
restart or fault lock-ou
Operating signal
Pilot burner closes
Flame proving period tFS1
running (P23)
In the event of flame failure:
fault lock-out
Main burner start-up
with ϑ2 signal
Wait until
min. burner pause time tBP
has elapsed (P21)
If parameter P15 = 0:
flame simulation check
If no flame detected:
max. 4 start-up attempts
or fault lock-out
Safety time tSA2 running (P22),
V2 opens and
min. combustion time tB
starts to elapse (P20)
Normal shut-down
via ϑsignal for
pilot and main burners
If min. combustion time t
B
has
elapsed:
Operation signalling contact
opens,
V1 and V2 close,
min. burner pause time t
BP
starts to elapse (P21)
In the event of flame failure:
restart or fault lock-out
Operating signal
Main burner closes
Flame proving period
tFS2 running (P24)
In the event of flame failure:
fault lock-out
BCU 480 program sequence4.2
Normal start-up
If an “old” fault is still being signalled
after switching on, it will be necessary
to reset this first.
The safety interlocks (terminal 5) must be
closed and the burner control unit must
be switched on.
The BCU 480 conducts a self-test when
in the start-up position (the burner is
switched off). If it does not determine a
malfunction of the internal electronic cir-
cuitry or of the flame sensors, the burner
can be started. The pilot burner start-up
is activated via the signal input “Start-up
signal V1” (terminal 4). Once the start-up
signal ϑ1 has been applied, the BCU 480
opens valve V1 and ignites the burner.
The ignition time tZ is constant. If a flame
is detected during the safety time tSA1, the
flame proving period tFS1 starts after the
safety time tSA1 has elapsed.
If the pilot burner has been started suc-
cessfully and its flame has stabilised, the
burner control unit issues the Enable
signal for main burner operation. The
operation signalling contact for the pilot
burner (terminals 16/17) closes.
BCU 480
If the air valve control is used,
the unit offers the following ad-
ditional functions:
In start-up position, the air valve
can be opened for cooling
A
(display
A0
).
Using parameter 31, it can be
determined whether the air valve
can be activated externally dur-
ing start-up (display
A1
).
The air valve can be set to open
together with V1 (display
A2
via
parameter 30.
Function
t

BCU 480 · Edition 06.07
17
01
01
02
03
04
08
00
00
08
05
06
07
Switch on BCU 480
Pilot burner start-up
with ϑ1 signal
Safety interlocks (Limits)
In the event of fault signal:
reset
If parameter P15 = 1:
flame simulation check
Wait until
min. burner pause time tW
has elapsed
If parameter P15 = 0:
flame simulation check
If no flame detected:
max. 4 start-up attempts
or fault lock-out
Start-up position/standby
Safety time tSA1
running (P22),
ignition in process,
V1 opens and min.
combustion time tB
starts to elapse (P20)
In the event of flame failure:
restart or fault lock-ou
Operating signal
Pilot burner closes
Flame proving period tFS1
running (P23)
In the event of flame failure:
fault lock-out
Main burner start-up
with ϑ2 signal
Wait until
min. burner pause time tBP
has elapsed (P21)
If parameter P15 = 0:
flame simulation check
If no flame detected:
max. 4 start-up attempts
or fault lock-out
Safety time tSA2 running (P22),
V2 opens and
min. combustion time tB
starts to elapse (P20)
Normal shut-down
via ϑsignal for
pilot and main burners
If min. combustion time t
B
has
elapsed:
Operation signalling contact
opens,
V1 and V2 close,
min. burner pause time t
BP
starts to elapse (P21)
In the event of flame failure:
restart or fault lock-out
Operating signal
Main burner closes
Flame proving period
tFS2 running (P24)
In the event of flame failure:
fault lock-out
The BCU coordinates the correct pro-
gram run for the pilot and main burn-
ers. The main burner can be started via
the signal input “Start-up signal ϑ2” (ter-
minal 21) if required. Once the start-up
signal ϑ2 has been applied (terminal 21),
the BCU 480 opens valve V2. The main
burner is ignited by the pilot burner. If a
flame is detected during the safety time
tSA2, the flame proving period tFS2 starts
after the safety time tSA2 has elapsed. If
the main burner has been started suc-
cessfully and its flame has stabilised, the
operation signalling contact (terminals
28/29) closes.
Start-up of the pilot burner without
flame signal
If no flame is detected during the safety
time t
SA1
, either a fault lock-out occurs
or up to three further start-up attempts
occur. The required functions and, if
applicable, the number of start-up at-
tempts must be specified when order-
ing. (Parameter 10, “Pilot burner start-up
attempts”).
The air valve can be set to open
together with V1 (display
A4
) via
parameter 30.
The air valve can be set to open
together with V1 (display
A3
) via
parameter 30.
The air valve can be set to open
together with V1 (display
A5
) via
parameter 30.
The air valve can be set to open
with V2 or to be activated exter-
nally (display
A6
) via parameter
30.
Function > BCU 480 program sequence
t

BCU 480 · Edition 06.07
18
01
01
02
03
04
08
00
00
08
05
06
07
Switch on BCU 480
Pilot burner start-up
with ϑ1 signal
Safety interlocks (Limits)
In the event of fault signal:
reset
If parameter P15 = 1:
flame simulation check
Wait until
min. burner pause time tW
has elapsed
If parameter P15 = 0:
flame simulation check
If no flame detected:
max. 4 start-up attempts
or fault lock-out
Start-up position/standby
Safety time tSA1
running (P22),
ignition in process,
V1 opens and min.
combustion time tB
starts to elapse (P20)
In the event of flame failure:
restart or fault lock-ou
Operating signal
Pilot burner closes
Flame proving period tFS1
running (P23)
In the event of flame failure:
fault lock-out
Main burner start-up
with ϑ2 signal
Wait until
min. burner pause time tBP
has elapsed (P21)
If parameter P15 = 0:
flame simulation check
If no flame detected:
max. 4 start-up attempts
or fault lock-out
Safety time tSA2 running (P22),
V2 opens and
min. combustion time tB
starts to elapse (P20)
Normal shut-down
via ϑsignal for
pilot and main burners
If min. combustion time t
B
has
elapsed:
Operation signalling contact
opens,
V1 and V2 close,
min. burner pause time t
BP
starts to elapse (P21)
In the event of flame failure:
restart or fault lock-out
Operating signal
Main burner closes
Flame proving period
tFS2 running (P24)
In the event of flame failure:
fault lock-out
Behaviour of the pilot burner in the
event of flame failure during operation
If the flame fails during operation, either
an immediate fault lock-out occurs or a
restart occurs. This procedure can be
set via the optical interface (parameter
12, “Pilot burner restart”).
Start-up of the main burner without
flame signal
If no flame is detected during the safety
time tSA2, either a fault lock-out occurs
or up to three further start-up attempts
occur. The required functions and, if
applicable, the number of start-up at-
tempts must be specified when order-
ing. (Parameter 11, “Main burner start-up
attempts”).
Behaviour of the main burner in the
event of flame failure during operation
If the flame fails during operation, either
an immediate fault lock-out occurs or a
restart occurs. This procedure can be
set via the optical interface (parameter
13, “Main burner restart”).
The air valve can be set to open
with V2 or to be activated exter-
nally (display
A7
) via parameter
30.
The air valve can be set to open
with the operating signal or to
be activated externally (display
A8 ) via parameter 30.
Function > BCU 480 program sequence

BCU 480 · Edition 06.07
19
Program status and fault messages4.3
During operation, the 7-segment display shows the program
status. In the event of a fault, the BCU halts the program run,
the display blinks and it then displays the cause of the fault.
The burner control unit can be reset using the Reset button
or the remote reset.
Program status DISPLAY Fault message (blinking*)
Start-up position/standby 00
Cooling A0
Waiting time/Pause time 1 Flame simulation, pilot burner
Safety time on start-up, pilot burner 2 Start-up without flame signal, pilot burner
Flame proving period, pilot burner 3 Flame failure during flame proving period, pilot burner
Operation, pilot burner 4 Flame failure during operation, pilot burner
Waiting time, main burner 5 Flame simulation, main burner
Safety time on start-up, main burner 6 Start-up without flame signal, main burner
Flame proving period, main burner 7 Flame failure during flame proving period, main burner
Operation, main burner 8 Flame failure during operation, main burner
Purge P0
Air valve AX No air flow in position X
High temperature operation** X.X.
* In Manual mode, two dots will blink on the display in program status 01 – 08 .
** Optionally available.
Function

BCU 480 · Edition 06.07
20
Parameters5
Description Parameter Value range Factory
default setting Adjustable*
Flame signal, pilot burner 01 0 – 99 μA
Flame signal, main burner 02 0 – 99 μA
Program status when the most recent fault occurred 03 x0 – x8
Switch-off threshold, pilot burner 04 1 – 20 µA 1 µA 
Switch-off threshold, main burner 05 1 – 20 µA 1 µA 
Start-up attempts, pilot burner** 10 1 – 4 1
Start-up attempts, main burner** 11 1 – 4 1
Restart, pilot burner 12 0; 1 0
Restart, main burner 13 0; 1 0
Safety time during operation for V1 and V2 tSB 14 1; 2 s 1 s
Flame simulation check in start-up position/standby 15 0; 1 1
Permanent pilot burner 16 0; 1 1
Minimum combustion time tB20 25 s tSA 
Minimum burner pause time tBP 21 0 – 250 s 0 s 
Pilot burner safety time on start-up tSA1** 22 3; 5; 10 s
Pilot burner flame proving period tFS1 23 0 – 25 s 0 s 
Main burner safety time on start-up tSA2** 24 3; 5 s
Main burner flame proving period tFS2 25 0 – 25 s 0 s 
Air valve control 30 0; 1; 2; 3 0
Air valve can be activated externally on start-up 31 0; 1 0
Air valve closed/can be activated in the event of malfunction 32 0; 1 1
t