Danfoss 057H8710 Handmatig - Pagina 9

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OBC 80 series

Application

The oil burner controls in the OBC 80 series are used to

control and monitor one or two-stage oil burners with

or without a preheater. The OBC 84.10 is used for burn-

ers with oil firing rates of 30 kg/h or above, and for hot

air devices. Other OBC controls are used for oil burners

with oil firing rates below 30 kg/h.

Mounting

Push the control's contact plugs into the base with 12

connection terminals. The control and base are held to-

gether by a spring system and can be released by press-

ing a screwdriver into the slot; see fig. 1. A front plate

with knockouts or a front plate designed for PG 11

screwed connections can be used; see fig. 2.

See fig. 3 for electrical connections in the base for the

various types.

• If using an LD or LDS photo unit, the blue wire must

be connected to terminal 11 and the black wire to ter-

minal 12. If using a UV sensor, the blue wire must be

connected to terminal 11, the black wire to terminal

12, and the brown wire to terminal 1.

• If preheater is not used, short-circuit terminals 3 and 8.

• If the control is equipped with a remote reset switch

connected to terminal 9, this switch must only be acti-

vated manually.

• On some OBC 80 models, the ignition unit may be

freely connected to either terminal 6 (TT1) or terminal

7 (TT2).

Note: On the OBC 85 the boiler thermostat (TR) must always

be connected to terminal 7, and the high temperature cut-

out (TB) must always be connected to terminal 1.

Function

The OBC controls the cut-in and cut-out of the oil

burner's components and monitors that the combustion

cycle is performed safely. See function diagrams, fig. 3.

When the boiler thermostat (TR) cuts in, heating of the

oil in the oil preheater (OFV) will begin.

Once the release temperature is reached and the oil pre-

heater's thermostat (OTR) cuts in, the burner motor will

start the pre-purge and power will simultaneously be

applied to the ignition (TT1/TT2). Following the pre-ig-

nition and pre-purge time, the oil will be released by

valve V1 being opened. On two-stage burners V2 will

subsequently be opened.

On OBC controls without post-purge, power will be cut

off when the boiler thermostat opens after the heating

period and all relays at the outputs will open and be

ready for the next start-up cycle.

On the OBC 85 control the power is not cut off when

the boiler thermostat opens, as power is still needed for

the burner motor so that post-purge can occur. Instead,

a timer function ensures that the burner motor continues

to run until the end of the post-purge time. If the ther-

mostat cuts in before the end of the postpurge time, the

control will interrupt the postpurge and start a new cy-

cle with pre-heating.

Operating information

OBC 80 controls are equipped with a twocoloured LED

which displays both the operating status and can indi-

cate the causes of errors leading to lockout.

In the event of operating lockout, the cause of error can

be read out as a flash code by holding down the reset

button for at least 5 seconds and then releasing it.

Undervoltage will, however, be displayed automatically.

Reset can be performed directly in alarm mode (constant

red light) or in flash code mode by pressing the reset

button for at least 0.5 seconds but no more than 3 sec-

onds.

In flash code mode it is possible to return to alarm

mode by holding down the reset button again for at

least 5 seconds.

VI.AA.A4.57

Normal operation

When the boiler thermostat (TR) cuts in, the reset button

flashes green. As soon as the preheater thermostat

(OTR) cuts in, the reset button lights up constant green;

see fig. 4.

When the boiler thermostat cuts out, the green light

turns off. On the OBC 85, the light does not turn off until

the post-purge period ends.

Errors during operation (flash codes; see fig. 5):

• If the mains voltage falls below 185 V before start-up,

the control will be blocked from starting. If the mains

voltage falls below 170 V during operation, the oil

supply and burner will be stopped. In both cases, the

reset button will automatically flash 8 times. When the

mains voltages reaches 185 V, the control will re-

start as normal. Please note that the control cannot be

reset if the mains voltage is below 170 V.

• If the mains voltage exceeds 264 V, the control will

automatically enter alarm mode. The purpose of the

overvoltage cut out is not simply to protect the elec-

tronics in the control, but also the other components

in the burner.

• If light is registered in the final stage of the pre-purge

time, the control will not release oil and will enter

alarm mode.

• If no flame is established at the start, i.e. by the end of

the safety time, the control will enter alarm mode.

• In the event of a flame failure during operation, the oil

supply will be cut off after no more than 1 second and

the control will restart the burner. If flame failure oc-

curs more than three times in the same operating pe-

riod (TR connected), the control will enter alarm mode.

Only one restart is allowed in the same operating period

for OBC 84.10.

• If the release temperature in the preheater is not

reached within 10 minutes, the control will enter

alarm mode.

The OBC 80 series' processors also monitor the outputs

at TT1/TT2, V1 and V2. If errors like electrical noise (EMC)

are registered at the outputs, the control will enter

alarm mode.

Troubleshooting

The OBC 80 series is approved in accordance with the

latest EN 298:2012 norm, which sets more stringent re-

quirements for the monitoring of safety functions than

previous norms. It is therefore important to ensure

proper connection in accordance with the diagrams

shown in order to avoid alarms.

When replacing the control in connection with service,

please ensure that:

• LD/LDS photo unit is connected to terminals 11 and

12. Common 0 on terminal 2 or connected auxiliary

terminals must not be used. Replacing the photo unit

is always recommended when replacing the control.

• If a certain function is not used, e.g. remote reset on

terminal 9, the connection cannot be used as an auxil-

iary terminal. Instead, the extra auxiliary terminals in

the base must be used.

• The ignition is connected to terminal 6, though this

does not apply to controls with alternate outputs for

ignition on terminal 7 (TT2).

• If an inverter which converts 12/24 V DC to 230 V AC is

used, ensure that the inverter is capable of producing

sinusoidal AC voltage. If the voltage is not sinusoidal,

the electronics will be overloaded (burn out). There is

also a risk that the control will detect an undervoltage.

• The photo unit/UV sensor is positioned correctly in

the burner so that the correct flame signal is generated.

UV sensors are particularly sensitive, as they are very

directional to prevent the ignition spark from being

regarded as false light.

• The photo unit/UV sensor is not sooty.

• The insulation of the associated wiring is not degraded,

as this can cause leakage currents that the control will

• The boiler thermostat switch contacts are not worn or

coated, as this can cause periodic supply power cuts.

• The cables to and from the control are positioned so

that they cannot generate electrical noise. Please be

particularly aware that high voltage cables from the

electronic ignition must not be placed against or wound

around the other electrical or electronic components,

such as the control itself and the pump's solenoid

valve.

Note: Automatic controls in the OBC 80 series can only be

reset while the supply voltage is connected.

Approvals

The controls in the OBC 80 series are approved in ac-

cordance with EN 298:2012:

Technical data

Rated voltage

Voltage range

Frequency

Supply fuse

Enclosure

Ambient temperature

Transportation & storage temperature

Undervoltage protection

Protection class

Pollution degree

Terminal loads

Terminal

Max. operating current

6 / 7

Note: Total operating current max. 5 A.

Conversion / Service

BHO 60 series

BHO 70 series

BHO 71.10

BHO 71A.10

BHO 64

BHO 72.10

BHO 64.1

BHO 72.11

BHO 64 A

BHO 73.10

LOA 44

BHO 74.10

230 V~

195 - 253 V~

50 - 60 Hz

max. 10 A

IP 40

-20 - +60°C

-30 - +70°C

< 170 V

5 A

1 A

5 A

1 A

OBC 80 series

OBC 81.10

OBC 81A.10

OBC 82.10

OBC 82.11

OBC 82A.12

OBC 84.10