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4.11 Control box for the air/fuel ratio (REC 27.100A2)
Important notes
To avoid accidents, material or environmental
damage, observe the following instructions!
The control box is a safety device! Avoid opening
WARNING
or modifying it, or forcing its operation. Riello
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 display and operating unit and incor-
rect settings of the fuel and / or air actuator posi-
tions can lead to dangerous burner operating
conditions.
All interventions (assembly and installation operations,
assistance, 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 opera-
tions, 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 func-
tions. In this case, the control box must not be operated,
even if it displays no evident damage.
During the programming of the control curves of the air-fuel
ratio, the technician should constantly observe the quality of
the combustion process (for example, using a gas analyser)
and, if the combustion values are too low or if there are dan-
gerous conditions, take the appropriate action, for example
by manually switching off the system.
The plugs of the connection cables or other accessories can
be removed or changed when the system is off.
The connections to the actuators do not provide a safe sepa-
ration of the mains voltage. Before connecting or changing
the actuators, the system should be switched off.
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
control box's electronic components when touched.
Technical description of the burner
17
GB
Installation notes
Arrange the HV ignition cables separately, as far as possible
from the control box and the other cables.
Check the electric wiring inside the boiler complies with the
national and local safety regulations.
Phase and neutral should not be exchanged (cause of dan-
gerous malfunctions, loss of protection against electric
shocks, etc..).
Make certain that strain relief of the connected cables is in
compliance with the relevant standards (e.g. as per
EN60730 e EN60 335).
Ensure that spliced wires cannot get into contact with neigh-
bouring terminals. Use adequate ferrules.
The mechanical connection between the actuators and the
elements for controlling the fuel and air, or other control ele-
ments, should be rigid.
When wiring the unit, make sure that AC 230V mains volt-
age cables are run strictly separate from extra low-voltage
cables to avoid risks of electrical shock hazard.
Mechanical structure
The control box is a system to check the burners, based on a mi-
croprocessor and equipped with components to adjust and mon-
itor medium and large capacity forced draught burners.
The base control box of the control box incorporates the following
components:
–
burner adjustment device with system for checking the seal
of the gas valves;
–
electronic fuel/air ratio monitoring device with a maximum of
2 actuators;
–
Modbus interface.
D8266
Fig. 6
20068435
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