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3.11 Control box for the air/fuel ratio (LMV51...)
Warning notes
To avoid injury to persons, damage to property or
the environment, the following warning notes must
be observed!
WARNING
The control box is a safety device! Do not open, in-
terfere with or modify the unit.
Riello S.p.A. will not assume responsibility for any
damage resulting from unauthorized interference!
Risk of explosion!
Incorrect configuration can lead to excessive fuel
supply which might cause an 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 actuator po-
sitions can lead to dangerous burner operating con-
ditions.
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 control box, completely isolate the plant from mains supply
(all-polar disconnection). Ensure that the plant cannot be inad-
vertently switched on again and that it is indeed dead. If not
observed, there is a risk of electric shock hazard.
Protection against electrical shock hazard on the control box
and on all connected electrical components must be ensured
through appropriate mounting.
Each time work has been carried out (mounting, installation
and service work, etc.), check to ensure that wiring is in an
orderly state, that the parameters have been correctly set and
make the safety checks.
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.
In programming mode, the position check of actuators and
VSD (checking electronic fuel / air ratio control) is different
from the check during automatic operation.
Like in automatic operation, the actuators are still jointly driven
to their required positions. If an actuator does not reach the
required position, corrections are made until that position is
reached. However, in contrast to automatic operation, there
are no time limits to these corrective actions.
The other actuators maintain their positions until all actuators
have reached the positions currently required.
This is essential for setting fuel /air ratio control.
This means that during the time the fuel / air ratio curves are
programmed, the person making the plant settings must con-
tinuously 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 danger-
ous situations, the commissioning engineer must take appro-
priate action (e.g. switching off manually).
To ensure the safety and reliability of the control box, the following
points must also be observed:
–
Condensation and ingress of humidity must be avoided.
Should such conditions occur, make sure that the unit will be
completely dry before switching on again!
–
Static charges must be avoided since they can damage the
unit's electronic components when touched.
20069791
Technical description of the burner
Mechanical design
The control box is a microprocessor-based burner management
system with matching system components for the control and su-
pervision of forced draft burners of medium to large capacity.
The following components are integrated in the control box:
•
•
•
•
Installation notes
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•
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•
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•
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12
GB
Burner control with gas valve proving system
Electronic fuel / air ratio control with a maximum of 4 actuators
Optional PID temperature / pressure controller (load controller)
Optional VSD moduleMechanical design
Ensure that the electrical wiring inside the boiler is in compli-
ance with national and local safety regulations.
Do not mix up live and neutral conductors.
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 neighbor-
ing terminals. Use adequate ferrules.
Always run high-voltage ignition cables separately while ob-
serving the greatest possible distance to the unit and to other
cables
The burner manufacturer must protect unused AC 230 V termi-
nals with dummy plugs (refer to sections Suppliers of other ac-
cessory items).
When wiring the unit, ensure that AC 230 V mains voltage ca-
bles are run strictly separate from extra low-voltage cables to
warrant protection against electrical shock hazard.
D9301
Fig. 7
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