BCU 370 · Edition 11.08l 51

L

VG

IC 20

B VA

GIK

L1

V1

4

DG min

9 3

VG..L

V2

5 32

23

21

24

13 17

18

19

20

BCU 370..I1..D3 25

DL

DL

7

DG

M

22

DG

11

DG

pe/2 UVS

29 30 31

26

28

90°

➔ 0

0 ➔ 90°

Parameters

4.5.5 Tightness test period tP

Parameter 26 on BCU..D3

Defines the tightness test period tP for the gas solenoid

valves.

Depending on burner capacity, the tightness of the gas

solenoid valves must be checked in accordance with

the relevant application standard, e.g. EN 676, EN 746,

NFPA 85 and NFPA 86.

It is possible to check a specific leakage rate V'

L using

the tightness control function. In countries where the

Standards and Directives of the European Union are

applicable, the maximum leakage rate V'

L is 0.1% of the

maximum flow rate [m3(ft3)/h (n)]. The sensitivity of

the tightness control can be adjusted by adapting the

test period tP for each individual application. If a small

leakage rate V'

L is to be detected, a long test period tP

must be set. The test period tP is the sum of the waiting

time tW, 3 s opening time tL and measurement time tM.

It is calculated from the inlet pressure pe [mbar (psig)],

the leakage rate V'

L [l/h (ft3/h)] and the test volume

VP [l (ft3)].

The test volume VP is determined using the opposite

table:

VP = VG + L x VM

tP = 4 x pe [mbar] x Vp [l]

V'L [l/h]

+ 1 s

DN Basic volume VG Volume per metre VM

Litres Quarts Litres Quarts

10 0.01 0.011 0.1 0.11

15 0.07 0.074 0.2 0.21

20 0.12 0.127 0.3 0.32

25 0.2 0.21 0.5 0.53

40 0.7 0.74 1.3 1.37

50 1.2 1.27 2 2.11

65 2 2.11 3.3 3.49

80 4 4.23 5 5.28

100 8.3 8.77 7.9 8.35

125 13.6 14.37 12.3 13

150 20 21.13 17.7 18.7

200 42 44.38 31.4 33.18

BCU 370 · Edition 11.08l 52

Parameters

4.5.6 Calculation example

Inlet pressure: pe = 50 mbar (0,725 psig)

Flow rate: V'

max = 15 m3/h (425,6 ft3/h)

Leakage rate VL:

V'

L = 15 m3/h (425,6 ft3/h) x 0.1% = 15 l/h (0,4256

ft3/h)

Test volume Vp:

2 x VG 20, gap: L = 0.5 m (19,68 inch)

Vp = 0.12 l + 0.5 m x 0.3 l = 0.27 l (0,28 qt)

Calculated test period:

tP = 4 x 50 x 0.27

15

+ 1 s = 7.6 s

Enter the next highest value using the software: 10 s.

BCU 370 · Edition 11.08l 53

Parameters

4.6 Air control

4.6.1 Valve control

Parameter 25

Determines whether an actuator connected to terminals 29 to 32 is activated for valve control.

If valve control is deactivated, the BCU 370 can be used

to control single-stage-controlled burners.

Parameter 25 = 1: Valve control is active. The BCU

activates the outputs on terminals 29, 30 and 31 to

move the actuator to the Open (pre-purge), Closed and

Ignition positions. When the appropriate position is

reached, this information is signalled back by the actuator via the input on terminal 32. The BCU 370 waits for

the feedback signal from the actuator once the outputs

have been activated. The time required depends on the

actuator running time. If the position is not reached

within the timeout time of 250 seconds, the BCU displays the fault message “Position not reached”.

Parameter 25 = 0: The BCU 370 runs through all program steps without waiting for a feedback signal from

the butterfly valve. The outputs for valve control are not

activated.

4.6.2 Pre-purge

Parameter 06

This parameter determines whether the BCU pre-purges on the next start-up after a normal shut-down.

Within the scope of the application standard EN 676

pre-purge can be dispensed with under certain conditions. This prevents cold air from entering the combustion chamber and accelerates burner start-up.

Parameter 06 = 1: Pre-purge occurs on each start-up.

Parameter 06 = 0: Pre-purge is omitted if the last shutdown was a normal shut-down and occurred within the

last 24 hours. After switching on the BCU, after a safety

shut-down or a fault lock-out or after a pause of more

than 24 hours, the BCU completes an entire pre-purge

cycle.

For burner capacities as from 70 kW, application standard EN 676 requires that a valve check be carried out if

pre-purge has been omitted.

For burner capacities as from 117 kW, application

standards NFPA 85 and NFPA 86 require a valve check

before pre-purge and pre-purge before each system

start.

The valves can be checked using a tightness control.

See “Function – Tightness control”. Please note application standards.

BCU 370 · Edition 11.08l 54

Parameters

4.6.3 Quick start starts in ...

Parameter 28, active if parameter 06 = 0 (“Quick start”)

and parameter 25 = 1 (“Valve control”).

Determines whether on quick start, the butterfly valve

rests in the Ignition position or in the Closed position

during standby.

In the Closed position, the amount of combustion air

which enters the combustion chamber is minimised.

Parameter 28 = 0: The BCU sets the butterfly valve to

the Ignition position for quick start after normal shutdown. Once the start-up signal (ϑ) has been applied,

the BCU initiates burner ignition immediately after the

fan run up time (parameter 20) and the waiting time.

Parameter 28 = 1: The BCU sets the butterfly valve to

the Closed position for quick start after normal shutdown. Once the start-up signal (ϑ) has been applied,

the BCU moves the actuator to the Ignition position via

the Open position and ignites the burner after the fan

run up time (parameter 20) and the waiting time. The

time between activating the start-up signal (ϑ) and

burner start is determined by the running time of the

actuator of the butterfly valve.

BCU 370 · Edition 11.08l 55

Parameters

4.6.4 Pre-purge time tPV

Parameter 18

88

ϑ

t

21

24

1

16

3

30

29

31

13

19-20

4 V1

6 V3

5 V2

17-18

11 DGmax.

9

32

DGmin.

7 DL

90° ➔ 0

0 ➔ 90°

tSA1

00 H0 05 06

tFS1 tE

01

tGV

P1 A2

tPV tZ1

03 04

tVZ

07 H8

tFS2

A1 08

tRF tSA2

Determines how long the full air flow will be supplied to

the combustion chamber before burner start.

Pre-purge removes non-combusted gases from the

combustion chamber.

The pre-purge time tPV starts once the actuator has signalled the Open position and the air pressure switch DL

contact has closed.

If “Pre-purge on each start-up” is deactivated (parameter 06 = 0), pre-purge is omitted on burner start after a

normal shut-down within the last 24 hours.

If the pre-purge time tPV is set to 0 s, pre-purge is always omitted, e.g. even on restart after a safety shutdown. The BCU carries out a quick start on each burner

start. The butterfly valve is moved to the Ignition position via the Open position after normal shut-down.

If tightness control is activated (BCU..D3, parameter 24

= 3), the pre-purge time tPV must be set to at least the

value of the test period (parameter 26).

The pre-purge time tPV is to be set on the basis of the

relevant application standard (e.g. EN 676, EN 746-2,

NFPA 85 or NFPA 86).

BCU 370 · Edition 11.08l 56

Parameters

4.6.5 Post-purge time tPN

Parameter 19

88

ϑ

t

21

24

1

16

3

30

29

31

13

19-20

4 V1

6 V3

5 V2

17-18

11 DGmax.

9

32

DGmin.

7 DL

90 ➔ 0

0 ➔ 90

08 P9 A0

tPN

00

Determines how long air will be supplied to the combustion chamber after burner operation has been terminated.

To remove combustion gas residues from the burner,

this can be purged with air after operation.

The post-purge time tPN starts to elapse once the startup signal (ϑ) has been deactivated or once the first

safety time has elapsed in case of a safety shut-down.

If the actuator is located above the Ignition position at

this time, it moves to the Ignition position. If it is below

the Ignition position, the actuator stays in its current

position.

Pre-purge on each start-up (parameter 06 = 1):

The actuator moves to the Closed position after the end

of the post-purge time tPN.

Quick start (parameter 06 = 0) or pre-purge time = 0

(parameter 18 = 0):

After the post-purge time tPN has elapsed, the actuator

moves to the Open position and then to the Ignition position (parameter 28 = 0) or the Low position (parameter

28 = 1).

If tightness control is activated (BCU..D3, parameter

24 = 3) and quick start is activated (parameter 06 = 0),

the post-purge time must be set to at least the value of

the test period (parameter 26).

BCU 370 · Edition 11.08l 57

Parameters

4.6.6 Fan run up time tGV

Parameter 20

88

ϑ

t

21

24

1

16

3

30

29

31

13

19-20

4 V1

6 V3

5 V2

17-18

11 DGmax.

9

32

DGmin.

7 DL

90° ➔ 0

0 ➔ 90°

tSA1

00 H0 05 06

tFS1 tE

01

tGV

P1 A2

tPV tZ1

03 04

tVZ

07 H8

tFS2

A1 08

tRF tSA2

This parameter defines the time between the activation

of the fan output (terminal 3) and the opening of the

butterfly valve or burner start.

Fan start with the butterfly valve being closed reduces

the start-up current of the fan motor.

BCU 370 · Edition 11.08l 58

Parameters

4.7 Control using PROFIBUS-DP

4.7.1 Bus control activation

Parameter 31 on BCU 370..B1-3

Activates three-point step control via Profibus-DP.

The activation signals for capacity control using the

butterfly valve can be transferred via the Profibus-DP.

Once bit 7 of the output byte has been set, the valve

moves in the direction of the Closed position. When

bit 6 is set, the valve moves to the Open position. If both

bits are set, the valve stops. The BCU 370 displays fault

message 56 , “Open + Close set simultaneously”.

The lower limit of the modulation range is defined using

Parameter 32.

4.7.2 Bus control limitation

Parameter 32 on BCU 370..B1-3

Defines the lower limit of the modulation range of the

butterfly valve.

Parameter 32 = 0: When bit 7 is activated, the butterfly

valve moves to the Closed position. This is defined by

the limit switch in the actuator.

Parameter 32 = 2: When bit 7 is activated, the butterfly

valve moves to the Ignition position. This is defined by

the limit switch in the actuator.

r

25 26 27 28 29 30 31 32

M

90°

➔ 0

0 ➔ 90°

▼

BCU 370 · Edition 11.08l 59

Parameters

Parameter 32 = 1: When bit 7 is activated, the butterfly

valve moves to the Low position. For this purpose, terminal 25 is wired to a fourth limit switch in the actuator.

r

25 26 27 28 29 30 31 32

M

90°

➔ 0

0 ➔ 90°

Min

Definition of the modulation range following

controller enable

BCU..B1-3 with three-point step control function

Valve position Output byte

Upper end position Open Bit 6

Lower end position Closed Bit 7, parameter 32 = 0

Lower end position Low

Bit 7, parameter 32 = 1,

terminal 25 wired to separate limit

switch

Lower end position Ignition Bit 7, parameter 32 = 2

BCU 370 · Edition 11.08l 60

Parameters

4.8 Manual mode

For convenient setting of the burner or analysing faults.

If the Reset/Information button is pressed for 2 s during switch-on, the BCU reverts to manual mode. Two

dots blink on the display.

In this operating mode, the burner control unit operates independently of the status of the inputs Start-up

signal (ϑ) (terminal 21), Controlled air flow (terminal

22) and Remote reset (terminal 23) as well as the bus

inputs on BCU..B1. The functions of the safety interlock

(terminal 24) are retained.

Each time after the button is pressed again, the BCU

moves to the next section of the program sequence and

stops there. After approx. 3 seconds, the flame signal is

indicated instead of the operating status. In the event

of flame simulation, the flame signal will be displayed

immediately.

Following controller enable (status display 08 ), a connected butterfly valve can be opened and closed as required. By holding the button, the motor is first opened

further. The BCU indicates A.1. . with blinking dots.

Once the button has been released, the butterfly valve

stops in the relevant position. If the button is pressed

again, the butterfly valve is closed (Closed position).

The BCU indicates A.0. . with blinking dots.

A change of direction takes place each time the button

is released and pressed again.

When the butterfly valve has reached its final position,

the dots disappear.

4.8.1 Operating time in manual mode

Parameter 16

Determines whether the BCU in manual mode is reset

to the standby position for manual mode.

Parameter 16 = 0: Manual mode is not limited in time.

If this function has been selected, operation of the

burner may be continued manually in the event of failure of the control system or the bus.

Parameter 16 = 1: Five minutes after the last time the

button is pressed, the BCU ends burner operation and

moves abruptly back to the standby position for manual

mode. The burner can be restarted manually.

Manual mode is terminated by switching off the BCU or

in the event of a power failure.

BCU 370 · Edition 11.08l 61

Parameters

4.9 Fault messages

4.9.1 The last 10 fault messages

Parameters 81 – 90

The BCU shows the last 10 fault messages.

In order to analyse a burner system, the last fault messages can be called up in the order in which they occurred. Extended diagnostics is possible using the

BCSoft software.

The BCU records the last 10 fault messages internally.

Parameter 81 shows the most recent fault message,

parameter 82 the one before and so on.

4.10 Password

4.10.1 User-defined password

Parameter 30, 4-digit number

Password saved to protect parameter settings.

To prevent unauthorised changes to parameter settings, a password is stored in parameter 30. Changes to

parameter settings can only be made once this number

has been entered. The password can be changed using

BCSoft. Note the effect of parameter settings on the

safe functioning of your system.

The password set at the factory can be found in the delivery note supplied.

BCU 370 · Edition 11.08l 62

Selection

5 Selection

BCU 370: For modulating-controlled forced draught burners

W Q I1 I2 I3 F E U0 U1 D1 D3 B1* -3*

BCU 370    v v    v  v v v

 = standard, v = available

* If “none”, this specifi cation is omitted.

Order example

BCU 370WI1FEU0D1

5.1 Type code

Code Description

BCU Burner control unit

W

Q

Mains voltage

230 V AC, 50/60 Hz

120 V AC, 50/60 Hz

I1

I2*

I3*

no specifi cation

Ignition

Electronic ignition, single-pole

Electronic ignition, double-pole

Electronic ignition, double-pole with neutral conductor

Without ignition

F Fan control

E Valve control

U0

U1

Flame control

Ionisation control (continuous or intermittent op.) or UV control (intermittent op. with UVS)

UV (continuous operation with UVD 1)

D1

D3

DGmax. monitoring

Integrated tightness control

B1 For PROFIBUS-DP

3 Three-point step control via PROFIBUS-DP

* I2 only for 230 V, I3 only for 120 V

Please quote the required settings of all parameters when ordering, see “Parameters”.

BCU 370 · Edition 11.08l 63

Project planning information

6 Project planning information

6.1 Cable selection

Use mains cable suitable for the type of operation and

complying with local regulations.

Signal and control line: Max. 1.5 mm2.

Control line for UVD 1 wiring: 1 mm2.

Cable for burner earth: 4 mm2.

Do not route BCU cables in the same cable duct as

frequency converter cables or cables emitting strong

fields.

6.1.1 Ionisation cable

Use unscreened high-voltage cable for the ionisation

cable (see Accessories).

Recommended cable length: Max. 50 m.

Lay cables individually, not in a metal conduit.

Install well away from mains cables and interference

from electro-magnetic sources.

Do not lay together with ignition cable.

6.1.2 UV cable

Cable length: Max. 50 m.

Install well away from mains cables and interference

from electro-magnetic sources.

Do not lay together with ignition cable.

6.1.3 Ignition cable

(BCU 370..I1, BCU 370..I2 with integrated electronic

ignition unit)

Use unscreened high-voltage cable (see Accessories).

Cable length: Max. 1 m.

Avoid external electrical interference.

Connect the ignition cable(s) securely to the integrated

ignition unit using the plug connector(s) (see Accessories).

Lay cables individually, not in a metal conduit.

Do not lay UV/ionisation cable and ignition cable(s) together and lay them as far apart as possible.

Feed out of the BCU on the shortest possible route (no

loops). Push through corresponding knock-out hole(s)

in the housing and use enclosed M16 cable gland(s).

Only use radio interference suppressed electrode

adapters (with 1 kΩ resistor), see “Accessories”.

For units with external ignition, e.g. ignition transformer

TGI, please note the corresponding unit instructions.

6.2 Fan control

The BCU features an output for fan control. The max.

start-up current of the fan motor may not exceed the

permitted contact rating (see Technical data) of this

output. If necessary, an external contactor must be

used.

BCU 370 · Edition 11.08l 64

Project planning information

6.3 Controlling the butterfly valve

The required burner commissioning time depends on

the running time of the butterfly valve actuator.

The BCU 370 waits for the feedback signal to indicate

that the actuator has reached the Open position, for instance, before the pre-purge time is started.

The Ignition position is always approached via the Open

position.

Once the butterfly valve has been set to the relevant

position, a plausibility check takes place. The related

control output is switched off briefly. The feedback signal must drop accordingly.

6.4 Safety interlock (Limits)

The limiters in the safety interlock (linking of all the relevant safety control and switching equipment for the

use of the application, for example STB [safety temperature limiter]) must isolate terminal 24 from the voltage

supply. If the safety interlock is interrupted, the display

shows a blinking 50 as a warning signal. The program

sequence is interrupted. All of the BCU 370’s outputs

are disconnected from the electrical power supply. The

burner control unit restarts when the safety interlock is

switched on again and the start-up signal (J) activated.

6.5 Too many remote resets

If a remote reset is made 5 times in 15 minutes (terminal 23 or by bus signal), the BCU is locked, shows fault

message 10 , “Too many remote resets”, and can only

be reset by pressing the Reset/Information button.

6.6 Protecting the ignition unit from

overload

The BCU protects the integrated ignition unit and the

electronic switch from overload. Excessive switching

triggers a warning signal (blinking 53 ). After the minimum cycle time has elapsed, the BCU starts.

The minimum cycle time saved in the BCU can be calculated using the formula:

Minimum cycle time = (tVZ + tSA1 - 1) x 6

Example:

Pre-ignition time tVZ = 2 s,

1st safety time on start-up tSA1 = 3 s

(2 s + 3 s - 1) x 6 = 24 s

In this example, the BCU 370 may not be started more

often than every 24 s.

If an external ignition unit/transformer is being used,

the formula is as follows:

Minimum cycle time = (tVZ + tSA1 - 1) x 2

Adjust the minimum burner pause time tPB (parameter

11) correspondingly, if required.

BCU 370 · Edition 11.08l 65

Project planning information

6.7 Wiring

The BCU is suitable for hard wiring only. Do not reverse

phase and neutral conductor. Different phases of a

three-phase current system must not be installed at

the inputs. Do not connect voltage to the outputs.

On BCU 370..B1 for PROFIBUS-DP, no voltage may be

connected to terminals 17 – 23. Otherwise, the BCU

may be damaged.

6.7.1 Single-electrode operation with external

ignition unit

BCU 370 13 14 15 16 PE N

If a burner only has one electrode, which is used for ignition and ionisation control, an external ignition transformer must be used, e.g. TZI or TGI.

6.8 BCU switched off

The BCU indicates –– . In general, it cannot be activated

when no mains voltage is applied or the burner control unit is switched off. The fault signalling contact is

only closed when the BCU is supplied with voltage and

switched on.

6.9 Note on EC or CSA and FM typeexamination

Since EN 298 (1993) or NFPA 85 and NFPA 86 does

not describe all functions of the BCU 370, the operator is responsible for ensuring that all parameters and

functions are matched to the respective application.

6.10 Contact protection devices

The safety-related switch contacts on the BCU 370, e.g.

for actuation of the gas solenoid valves, are protected

by an internal fuse. This fuse cannot be replaced, since

safe opening of the contacts is not guaranteed following overload or a short-circuit, e.g. due to a wiring fault.

The BCU must be returned to the manufacturer for repair.

6.11 Installation

Recommended installation position: vertical (cable

glands pointing downwards).

Detach the upper section of the BCU, remove and screw

on lower section with four screws Ø 4 mm. Replace upper section and screw into place.

BCU 370 · Edition 11.08l 66

Project planning information

6.12 Protective circuits

Connected control elements must be equipped with

protective circuits in accordance with the manufacturer’s instructions. This prevents high voltage peaks

which can cause malfunction of the BCU.

BCU 370 · Edition 11.08l 67

Flame control

7 Flame control ...

7.1 ... with ionisation sensor

The BCU generates an alternating voltage (230 V AC)

between the sensing electrode and burner earth. The

flame rectifies this voltage. Only the DC signal (>1 μA) is

detected by the burner control unit.

A flame cannot be simulated.

Ignition and monitoring with a single electrode are possible if an external ignition transformer is used.

7.2 ... with UV sensor

A UV tube inside the UV sensor detects the ultraviolet

light of a flame. It does not respond to sunlight, incandescent bulb light or infrared radiation emitted by hot

workpieces or red-hot furnace walls.

In the event of incident UV radiation the UV sensor rectifies the supplied alternating voltage. As with ionisation control, the burner control unit only detects this DC

signal.

When using UV sensors of Type UVS, the burner control

unit may be used for intermittent operation only. This

means that operation must be interrupted at least once

every 24 hours. This can be programmed using parameter 17.

For further information, see brochure UVS.

The burner control unit BCU.. U1 is prepared for UV sensor UVD 1. This enables continuous operation.

See Connection diagrams BCU 370/BCU 370..U1.

BCU 370 · Edition 11.08l 68

Accessories

8 Accessories

8.1 High-voltage cable

FZLSi 1/7 up to 180 °C (356 °F), Order No.: 04250410,

FZLK 1/7 up to 80 °C (176 °F), Order No.: 04250409.

8.2 BCSoft

Opto-adapter including BCSoft CD-ROM

Order No.: 74960437

The current software can be downloaded from our Internet site at

www.docuthek.com.

Log on to the Docuthek and then choose document

type “Software”.

8.3 Radio interference suppressed electrode

adapters

Plug cap, 4 mm, interference-suppressed,

Order No.: 04115308.

Straight adapter, 4 mm, interference-suppressed,

Order No.: 04115307.

Straight adapter, 6 mm, interference-suppressed,

Order No.: 04115306.

8.4 Connection kit BCU 370

2 M16 cables glands,

2 plug connectors for ignition cable,

2 seal inserts for M20 cable glands.

The connection kit is included in the scope of delivery

for the lower section.

Order No.: 74960479

8.5 Set of stickers BCU 370

Various stickers with information in the following languages: D, F, I, NL and E,

sticker: “Important, changed parameters”.

The set of stickers is included in the scope of delivery for

the upper section.

Order No.: 74960480

8.6 Device master data file for BCU 370..B1

The DMD file can be downloaded from our Internet site at

www.docuthek.com.

Log on to the Docuthek and then choose document

type “Software”.

Device master data file on diskette

Order No.: 74960460

BCU 370 · Edition 11.08l 69

Technical data

9 Technical data

Mains voltage:

BCU..W: 230 V AC, -15/+10%, 50/60 Hz, or

BCU..Q: 120 V AC, -15/+10%, 50/60 Hz,

for grounded or ungrounded mains.

Flame control with UV sensor or ionisation sensor.

Flame signal for:

Ionisation control: 1 – 28 μA,

UV control: 1 – 35 μA.

For intermittent or continuous operation.

Air pressure check during pre-purge and operation by

external air pressure switch DL.

Maximum length of ignition cable with integrated electronic ignition: 1 m.

Maximum length of ionisation/UV cable: 50 m (164 ft).

Max. number of operating cycles: 250,000.

Ambient temperature:

BCU 370: -20 – +60 °C (-4 – +140 °F),

BCU 370..I: -10 – +60 °C (14 – +140 °F),

no condensation permitted.

Enclosure: IP 54 pursuant to IEC 529.

Housing made of impact-resistant and heat-resistant

plastic. Plug-in upper section with operating and display elements.

Lower section with connection terminals, earthing strip

and pre-wired neutral bus with spacious wiring chamber.

1x M25 multiple screw connector, 4x 7 mm cable grommets,

2x M20 multiple screw connectors, 2x 7 mm cable

grommets, and loosely enclosed

1x or 2x M16 plastic screw connector(s) for the ignition

cable(s).

Voltage to inputs, valves, fan, controller enable, actuator

and ignition unit = mains voltage.

Power consumption: Approx. 9 VA plus approx. 50 VA for

integrated ignition.

Input voltage signal inputs:

Rated value 120 V AC 230 V AC

Signal “1” 80 – 126.5 V 160 – 253 V

Signal “0” 0 – 20 V 0 – 40 V

Input current signal “1”: Typ. 2 mA

Output to ignition transformer:

No-switch contacts via semi-conductor.

▼

BCU 370 · Edition 11.08l 70

Technical data

Contact rating:

Valves: Max. 1 A, cos

j = 1,

Butterfly valves: Max. 1 A, cos

j = 1,

Ignition: Max. 1 A, cos

j = 0.3,

Controller enable signal: Max. 1 A, cos

j = 1,

the contacts may be loaded with a max. total of 2.5 A,

Fan: Max. 3 A, start-up current: Max. 6.5 A < 1 s.

The outputs may be loaded with a max. total of 4 A.

Operation and fault signalling contacts:

Dry Contact, max. 1 A, 253 V, not fused internally.

Reset/Information button: Max. number of operating

cycles: 1000.

Fuse in BCU, replaceable, F1: T 5A H, pursuant to

IEC 60127-2/5.

Permissible UV sensors:

Elster Kromschröder models UVS 1, 5, 6, 8 and UVD 1.

Weight: Approx. 1.8 kg. 9.1 PROFIBUS-DP

Manufacturer ID: 0x08EC.

ASIC type: SPC3.

SYNC- and FREEZE-capable.

Baud rate detection: Automatic.

Min. cycle time: 0.1 ms.

Diagnostic bytes: 6 (DP Standard).

Parameter bytes: 7 (DP Standard).

BCU 370 · Edition 11.08l 71

A

B

C

D

E

200

90

50

170

185

154

138

ø 5

A

B

C

D

E

200

90

50

170

185

154

138

ø 5

Technical data

9.2 Operating controls and dimensions

A: 2-digit 7-segment display

B: Off switch, deactivates the BCU, outputs are disconnected from the electrical power supply

C: Reset/Information button to reset the system after

a fault, to scan parameters on the display or to control manual operation

D: Optical interface

E: BCU label with the most important status messages

in English

Additional stickers in D, F, I, NL and E enclosed

BCU 370 · Edition 11.08l 72

Legend

10 Legend

88 Display

88 Blinking display

Ready

Safety interlock (Limits)

Start-up signal

Controlled air flow

Ignition transformer

Gas valve

Flame signal

Operating signal

Fault signal

Reset

Input signal

Output signal

Flame simulation check

p

Pressure switch

(DL for air, DG for gas)

Ignition/Ignition position

Three-point step controller

M

Actuator (in connection diagram)

BCU 370 · Edition 11.08l 73

Glossary

11 Glossary

11.1 Safety shut-down

After an installation fault (e.g. flame or air pressure

failure), the burner control unit performs a safety shutdown. This involves disconnecting the power from the

gas valves and the ignition transformer. The operation

signalling contact and the controller enable signal are

deactivated.

After a safety shut-down, the burner control unit can

either restart or perform a fault lock-out, depending on

the parameter settings.

11.2 Fault lock-out

In the event of a fault lock-out, the fault signalling contact closes, the display blinks and shows the current

program status (see table Fault messages). Gas valves

and ignition transformer are disconnected from the

electrical power supply.

After a fault lock-out, the burner control unit can be reset manually with the button on the front panel or using

an external button. Several BCUs can be reset at the

same time via an external button.

The BCU cannot be reset by mains failure (fault lock-out

which cannot be changed). The fault signalling contact

does, however, open as soon as the mains voltage fails.

11.3 Warning signal

The BCU 370 reacts to operating faults, e.g. in the case

of permanent remote resets, with a warning signal. The

display blinks and shows the corresponding warning

message. The warning signal ends once the cause has

been eliminated.

The program sequence continues. No fault signal is activated (terminals 19/20).

11.4 Timeout 25 s/250 s

For some process faults, a timeout phase elapses before the BCU 370 reacts to the fault. The phase begins

as soon as the BCU 370 detects a process fault and

ends after 25 s or 250 s. A safety shut-down or a fault

lock-out then occurs. If the process fault ends during

the timeout phase, the process continues as before.

BCU 370 · Edition 11.08l 74

Annex

12 Annex

12.1 Status and fault messages for PROFIBUS-DP

This table can be used to program the master.

Input bytes (BCU ➔ master)

Byte 2 Byte 0, Bit 2 = 0 (Status message) Byte 0, Bit 2 = 1 (Fault message)

0 0 Start-up position/standby

1 A0 Valve moves to Closed position 01 Flame simulation

2 01 Fan run up time

3 A1 Butterfly valve moves to Open position

4 P1 Pre-purge time 04 Start-up without flame signal

5 A2 Butterfly valve moves to Ignition position 05 Flame failure during 1st flame proving period

6 03 Pre-ignition time 06 Flame failure during 2nd safety time

7 04 1st safety time on start-up 07 Flame failure during 2nd flame proving period

8 05 1st flame proving period 08 Flame failure during operation

9 06 2nd safety time on start-up

10 07 2nd flame proving period d0 Fault Air monitor break contact check

11 08 Controller enable signal d1 Fault Air monitor make contact check

12 P9 Post-purge time d2 Fault Air supply while butterfly valve moves to Ignition position

13 d3 Fault Air supply during pre-ignition time

14 d4 Fault Air supply during 1st safety time on start-up

15 d5 Fault Air supply during 1st flame proving period

16 d6 Fault Air supply during 2nd safety time on start-up

17 d7 Fault Air supply during 2nd flame proving period

18 d8 Fault Air supply during operation

19 dP Fault Air supply during pre-purge time

▼

BCU 370 · Edition 11.08l 75

Annex

Input bytes (BCU ➔ master)

Byte 2 Byte 0, Bit 2 = 0 (Status message) Byte 0, Bit 2 = 1 (Fault message)

20 u0 Fault DGmin during standby

21 u1 Fault Dgmin while butterfly valve moves to Open

position

22 u2 Fault DGmin while butterfly valve moves to Closed

position

23 u3 Fault DGmin during pre-ignition time

24 u4 Fault DGmin during 1st safety time on start-up

25 u5 Fault DGmin during 1st flame proving period

26 u6 Fault DGmin during 2nd safety time

27 u7 Fault DGmin during 2nd flame

proving period

28 u8 Fault DGmin during operation

29 u9 Fault DGmin during post-purge time

30 o0 Fault DGmax in start-up position/standby

31 o1 Fault DGmax while butterfly valve moves to Open position

32 o2 Fault DGmax while butterfly valve moves to Closed position

33 o3 Fault DGmax during pre-ignition time

34 o4 Fault DGmax during 1st safety time during operation

35 o5 Fault DGmax during 1st flame proving period

36 o6 Fault DGmax during 2nd safety time during operation

37 o7 Fault DGmax during 2nd flame proving period

38 o8 Fault DGmax during operation

▼

BCU 370 · Edition 11.08l 76

Annex

Input bytes (BCU ➔ master)

Byte 2 Byte 0, Bit 2 = 0 (Status message) Byte 0, Bit 2 = 1 (Fault message)

39 o9 Fault DGmax during post-purge time

40 A0 Butterfly valve closed position not reached

41 A1 Butterfly valve open position not reached

42 A2 Butterfly valve ignition position not reached

50 10 Too many remote resets

58 bE Bus module error

61 31 CRC error parameter

62 32 Undervoltage

63 33 EEprom parameter exceeds limit valvue

65 35 Fault Valve feedback

66 36 Tightness control: V1 leaking

67 37 Tightness control: V2/V3 leaking

80 50 Safety interlock failure

82 52 Permanent remote reset

83 53 Timing cycle too short

85 55 DGmin oscillating

86 56 Open + Close set simultaneously

99 99 Internal error

100 H0 Switch-on delay time/pause time

104 C1 Controlled air flow

108 H8 Controller enable signal delay time

BCU 370 · Edition 11.08l

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Remarks

Elster GmbH

Postfach 2809 · 49018 Osnabrück

Strotheweg 1 · 49504 Lotte (Büren)

Germany

Tel +49 541 1214-0

Fax +49 541 1214-370

info@kromschroeder.com

www.kromschroeder.com

Contact

The current addresses of our international agents

are available on the Internet:

www.kromschroeder.de/Weltweit.20.0.html?&L=1

We reserve the right to make technical

modifications in the interests of progress.

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