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3.12 Control box for the air/fuel ratio (LMV52...)
Warnings
To avoid accidents, material or environmental dam-
age, observe the following instructions!
The control box is a safety device! Avoid opening or
WARNING
modifying it, or forcing its operation. Riello S.p.A.
cannot assume any responsibility for damage re-
sulting 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 actuator po-
sitions can lead to dangerous burner operating con-
ditions.
All interventions (assembly and installation operations, assis-
tance, etc.) must be carried out by qualified personnel.
Before modifying the wiring in the control box connection 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 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 posi-
tion is actually 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 absolutely important to set the fuel / air ratio control
system. During the time the fuel / air ratio curves are being
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 analyser).
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 follow-
ing 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 con-
trol box's electronic components when touched.
20146383
Technical description of the burner
Mechanical structure
The control box is a system to check the burners, based on a mi-
croprocessor and equipped with components to adjust and monitor
medium and large capacity forced draught burners.
The base control box incorporates the following components:
• Burner control with gas valve proving system
• Electronic fuel / air ratio control with a maximum of 6 actuators
• Optional PID temperature / pressure controller (load controller)
• Optional VSD module Mechanical design
14
GB
D9301
Fig. 8
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