Siemens Oil Burner Control Service Manual
118
7
LOA2... LOA3...
Oil Burner Controls LOA2...
LOA3...
Oil burner controls for the supervision, startup and control of 1- or 2-stage forced
draft oil burners in intermittent operation.
Oil throughput up to 30 kg/h.
The LOA2... / LOA3... and this Data Sheet are intended for use by OEMs which
integrate the oil burner controls in their products.
Use, features
Use
General features
Specific features
The LOA... are used for the startup, supervision and control of 1- or 2-stage forced draft
oil burners in intermittent operation.
Yellow-burning flames are supervised with photoresistive detectors QRB..., blueburning flames with blue-flame detectors QRC...
- Forced draft oil burners conforming to EN 267
- Oil atomization burners in monoblock design conforming to EN 230
- Undervoltage detection
- Bridging contact for oil preheater (not with LOA28.173A27)
- Special versions including models for incinerator plant and flash-steam generators
- LOA36... with color LED for indicating flame strength and operation
CC1N7118en
16.12.2005
Building Technologies
HVAC Products
Warning notes
Mounting notes
Installation notes
To avoid injury to persons, damage to property or the environment, the following
warning notes should be observed!
Do not open, interfere with or modify the unit!
• All activities (mounting, installation and service work, etc.) must be performed by
qualified staff
• Before making any wiring changes in the connection area of the LOA..., completely
isolate the unit 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 indicated in «Commissioning notes» above
• Press the lockout reset button / operating button only manually (applying a force of
no more than 60 N), without using any tools or pointed objects
• Fall or shock can adversely affect the safety functions. Such units must not be put
into operation, even if they do not exhibit any damage
• Ensure that the relevant national safety regulations are complied with
• Do not mix up live and neutral conductors
• Always run high-voltage ignition cables separately while observing the greatest
possible distance to the unit and to other cables
• Install switches, fuses, earthing, etc., in compliance with local regulations
• Ensure that the maximum permissible amperages will not be exceeded (refer to
«Technical data»)
Electrical connection of flame detectors
It is important to achieve practically disturbance- and loss-free signal transmission:
• Never run the detector cable together with other cables
– Line capacitance reduces the magnitude of the flame signal
– Use a separate cable
• Observe the permissible lengths of the flame detector cables (refer to Data Sheets
N7714 (QRB...) and N7716 (QRC...))
Commissioning notes
• When commissioning the plant, when carrying out maintenance work, or after
longer off periods, make the following safety checks:
Safety check Anticipated response
a) Burner startup with flame detector
darkened
b) Burner startup with flame detector
exposed to extraneous light
c) Simulation of flame failure during
operation. For that purpose, darken
the flame detector during operation
and maintain this state
Lockout at the end of «TSA»
Lockout after approx. 40 seconds
Repetition followed by lockout at the
end of «TSA»
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Standards and certificates
Service notes
Conformity to EEC directives
- Electromagnetic compatibility EMC (immunity)
- Low-voltage directive
ISO 9001: 2000
Cert. 00739
ISO 14001: 2004
Cert. 38233
Type reference
LOA24.171B17 x
LOA24.171B27 x
LOA24.173A27 x
LOA24.571C27 x
LOA25.173C17 --LOA25.173C27 --LOA26.171B27 x
LOA28.173A27 x
LOA36.171A27 x
• Use the KF... test adapters for short periods of time only
89 / 336 / EEC
73 / 23 / EEC
Disposal notes
Mechanical design
The unit contains electrical and electronic components and must not be disposed of
together with domestic waste.
Local and currently valid legislation must be observed.
The housing is made of impact-proof, heat-resistant and flame-retarding plastic.
The oil burner control is of plug-in design and engages audibly in its base.
The housing accommodates the
- thermal-electric sequence switch
- flame signal amplifier with the flame relay
- lockout reset button with its integrated fault indication lamp
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Type summary
The type references given below apply to burner controls without base and without flame detector.
Version Type reference Voltage Under-
voltage
detection
Standard version
For flash-steam generators LOA24.571C27 AC 220 V X X 5 s 6 10 s 20 s --- 20 s
For incinerator plant
LOA24.171B27 ²) AC 220 V X X 13 s 13 s 10 s 20 s --- 20 s
LOA24.171B17 ²) AC 110 V X X 13 s 13 s 10 s 20 s --- 20 s
LOA24.173A27 AC 220 V X X 13 s 13 s 10 s 20 s 2 s 20 s
LOA26.171B27 ²) AC 220 V X X 13 s 13 s 10 s 20 s --- 20 s With remote reset facility
LOA36.171A27 AC 220 V X X 13 s 13 s 10 s 20 s --- 20 s
LOA25.173C27 ¹) AC 220 V X --- 13 s 13 s 10 s --- 2 s 20 s
LOA25.173C17 ¹) AC 110 V X --- 18 s 13 s 10 s --- 2 s 20 s
LOA28.173A27 ¹) AC 220 V X --- 13 s 13 s 10 s --- 2 s 20 s
CE t1 t3 TSAmax. t3n t3n´ t4
Legend
¹)
²)
t1 Prepurge time
t3 Preignition time
t3n Long postignition time
t3n´ Short postignition time
t4
TSAmax. Ignition safety time
LOA25... and LOA28... are designed for use on incinerator plant where lockout by extraneous light is not desired.
These types of oil burner controls are not covered by EN 230
IRD1010 infrared flicker detectors can also be used
Interval from establishment of flame to the release of «BV2»
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Building Technologies CC1N7118en
HVAC Products 16.12.2005
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