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13
20040170
GB
Technical description of the burner
4.13 Control box for the air/fuel ratio (LMV52...)
Warnings

All interventions (assembly and installation operations,
assistance, etc.) must be carried out by qualified personnel.

Before modifying the wiring in the LMV52 control box con-
nection area, fully disconnect the system from the power
supply (omnipolar separation). Check the system is not
powered and cannot be accidentally reconnected. Failure to
do this will lead to the risk of electrocution.

Protection against electrocution from the LMV5... control
box and all connected electric components is obtained with
correct assembly.

Before any intervention (assembly and installation operations,
assistance, etc.), ensure the wiring is in order and that the
parameters are correctly set, then make the safety checks.

Falls and collisions can negatively affect the safety functions.
In this case, the control box must not be operated, even if it
displays no evident damage.

In programming mode, the position check of actuators and
VSD (checking electronic fuel / air ratio control) is different
from the check during automatic operation.
As for automatic operation, the actuators are guided
together to the positions requested and, if an actuator does
not reach the position requested, adjustments are made
until the position is actually reached. However, in contrast to
automatic operation, there are no time limits to these cor-
rective actions.
The other actuators maintain their positions until all actua-
tors have reached the positions currently required.
This is absolutely important to set the fuel / air ratio control
system.
During the time the fuel / air ratio curves are being pro-
grammed, the person making the plant settings must contin-
uously monitor the quality of the combustion process (e.g. by
means of a flue gas analyzer).
Also, if combustion levels are poor, or in the event of dan-
gerous situations, the commissioning engineer must take
appropriate action (e.g. switching off manually).
To ensure the safety and reliability of the LMV5... system, the
following instructions must also be followed:
–
Avoid conditions that can favour the development of conden-
sate and humidity. Otherwise, before switching on again,
make sure that the entire control box is perfectly dry!
– Static charges must be avoided since they can damage the
control box’s electronic components when touched.
Mechanical structure
The LMV5... control box is a system to check the burners, based
on a microprocessor and equipped with components to adjust
and monitor medium and large capacity forced draught burners.
The base control box of the LMV5... system incorporates the fol-
lowing components:
• Burner control with gas valve proving system
• Electronic fuel / air ratio control with a maximum of 4 (LMV51…)
or 6 (LMV52…) actuators
• Optional PID temperature / pressure controller (load controller)
• Optional VSD module Mechanical design
Installation notes
• Check the electric wiring inside the boiler complies with the na-
tional and local safety regulations.
• Do not confuse the powered conductors with the neutral ones.
• Make certain that strain relief of the connected cables is in
compliance with the relevant standards (e.g. as per DIN EN
60730 and DIN EN 60 335).
• Ensure that spliced wires cannot get into contact with neigh-
boring terminals. Use adequate ferrules.
• Arrange the HV ignition cables separately, as far as possible
from the control box and the other cables.
• The burner manufacturer must protect unused AC 230 V ter-
minals with dummy plugs (refer to sections Suppliers of other
accessory items).
• When wiring the unit, make sure that AC 230 V mains voltage
cables are run strictly separate from extra low-voltage cables
to avoid risks of electrical shock hazard.
Electrical connection of ionization probe and flame detector
It is important for signal transmission to be almost totally free
of any disturbances or loss:
• always separate the detector cables from the other cables:
– Line capacitance reduces the magnitude of the flame signal.
– Use a separate cable.
• Respect the allowed cable lengths.
• The ionisation probe is not protected against the risk of elec-
trocution. When connected to the electricity supply, the ionisa-
tion probe must be protected against any accidental contact.
WARNING
To avoid accidents, material or environmental
damage, observe the following instructions!
The LMV52 control box... is a safety device! Avoid
opening or modifying it, or forcing its operation. Riel-
lo S.p.A. cannot assume any responsibility for dam-
age resulting from unauthorised interventions!
Risk of explosion!
An incorrect configuration can provoke fuel over-
charging, with the consequential risk of explosion!
Operators must be aware that incorrect settings
made on the AZL5… display and operating unit
and incorrect settings of the fuel and / or air actu-
ator positions can lead to dangerous burner oper-
ating conditions.
Fig. 7
D9301