Riello 826 T2 Quick start guide

Installation, use and maintenance instructions
20068417 (7) - 02/2023
Forced draught gas burners
Progressive two-stage or modulating operation
CODE MODEL TYPE
3781632 - 3781633 RS 50/E MZ 826 T2
GB

Translation of the original instructions

1 20068417
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Contents
1 Information and general warnings............................................................................................................................................ 3
1.1 Information about the instruction manual .................................................................................................................... 3
1.1.1 Introduction.................................................................................................................................................................. 3
1.1.2 General dangers.......................................................................................................................................................... 3
1.1.3 Other symbols ............................................................................................................................................................. 3
1.1.4 Delivery of the system and the instruction manual...................................................................................................... 4
1.2 Guarantee and responsibility....................................................................................................................................... 4
2 Safety and prevention................................................................................................................................................................ 5
2.1 Introduction.................................................................................................................................................................. 5
2.2 Personnel training ....................................................................................................................................................... 5
3 Technical description of the burner ......................................................................................................................................... 6
3.1 Burner designation ...................................................................................................................................................... 6
3.2 Models available.......................................................................................................................................................... 6
3.3 Burner categories........................................................................................................................................................ 7
3.4 Technical data............................................................................................................................................................. 7
3.5 Electrical data.............................................................................................................................................................. 7
3.6 Maximum dimensions.................................................................................................................................................. 8
3.7 Firing rate .................................................................................................................................................................... 8
3.7.1 Firing rate on basis of air density ................................................................................................................................ 9
3.8 Test boiler.................................................................................................................................................................. 10
3.9 Burner equipment...................................................................................................................................................... 10
3.10 Burner description ..................................................................................................................................................... 11
3.11 Control box for the air/fuel ratio (REC 27.100A2)...................................................................................................... 12
3.12 Operation sequence of the burner............................................................................................................................. 15
3.12.1 List of phases ............................................................................................................................................................ 16
3.13 Operator panel operation .......................................................................................................................................... 16
3.13.1 Symbols description on the display........................................................................................................................... 16
3.13.2 Buttons description.................................................................................................................................................... 17
3.14 Servomotors (SQN13...)............................................................................................................................................ 18
4 Installation ................................................................................................................................................................................ 19
4.1 Notes on safety for the installation ............................................................................................................................ 19
4.2 Handling .................................................................................................................................................................... 19
4.3 Preliminary checks .................................................................................................................................................... 19
4.4 Operating position ..................................................................................................................................................... 20
4.5 Preparing the boiler................................................................................................................................................... 20
4.5.1 Boring the boiler plate ............................................................................................................................................... 20
4.5.2 Blast tube length........................................................................................................................................................ 20
4.6 Positioning probe - electrode..................................................................................................................................... 21
4.7 Securing the burner to the boiler............................................................................................................................... 22
4.8 Combustion head adjustment.................................................................................................................................... 22
4.9 Burner closing ........................................................................................................................................................... 23
4.10 Gas feeding............................................................................................................................................................... 24
4.10.1 Gas feeding line ........................................................................................................................................................ 24
4.10.2 Gas train.................................................................................................................................................................... 25
4.10.3 Gas train installation.................................................................................................................................................. 25
4.10.4 Gas pressure............................................................................................................................................................. 25
4.11 Electrical wiring ......................................................................................................................................................... 27
4.11.1 Supply cables and external connections passage .................................................................................................... 27
4.12 Calibration of the thermal relay ................................................................................................................................. 28
5 Start-up, calibration and operation of the burner ................................................................................................................. 29
5.1 Notes on safety for the first start-up .......................................................................................................................... 29
5.2 Adjustments prior to ignition ...................................................................................................................................... 29
5.3 Burner start-up .......................................................................................................................................................... 29
5.4 Burner adjustment..................................................................................................................................................... 30
5.4.1 Firing output .............................................................................................................................................................. 30
5.4.2 Maximum output........................................................................................................................................................ 30
5.4.3 Minimum output......................................................................................................................................................... 30

20068417 2
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Contents
5.5 Final calibration of the pressure switches ..................................................................................................................31
5.5.1 Air pressure switch.....................................................................................................................................................31
5.5.2 Maximum gas pressure switch...................................................................................................................................31
5.5.3 Minimum gas pressure switch....................................................................................................................................32
5.5.4 PVP pressure switch kit .............................................................................................................................................32
5.6 Visualisation and programming mode........................................................................................................................33
5.6.1 Normal mode .............................................................................................................................................................33
5.6.2 Info mode ...................................................................................................................................................................34
5.6.3 Service mode .............................................................................................................................................................35
5.6.4 Parameter mode ........................................................................................................................................................35
5.7 Parameter modification procedure.............................................................................................................................36
5.8 Start-up procedure .....................................................................................................................................................38
5.9 Backup / Restore procedure ......................................................................................................................................40
5.9.1 Backup .......................................................................................................................................................................40
5.9.2 Restore ......................................................................................................................................................................41
5.9.3 Parameter list.............................................................................................................................................................43
5.10 Steady-state operation...............................................................................................................................................47
5.11 Ignition failure.............................................................................................................................................................47
5.12 Burner flame goes out during operation.....................................................................................................................47
5.13 Stopping of the burner ...............................................................................................................................................47
5.14 Final checks (with burner operating)..........................................................................................................................48
6 Maintenance ..............................................................................................................................................................................49
6.1 Notes on safety for the maintenance .........................................................................................................................49
6.2 Maintenance programme ...........................................................................................................................................49
6.2.1 Maintenance frequency..............................................................................................................................................49
6.2.2 Safety test - with gas ball valve closed ......................................................................................................................49
6.2.3 Checking and cleaning...............................................................................................................................................49
6.2.4 Safety components ....................................................................................................................................................50
6.2.5 Measuring the ionisation current................................................................................................................................51
6.2.6 Checking the air and gas pressure on the combustion head.....................................................................................51
6.3 Opening the burner ....................................................................................................................................................52
6.4 Closing the burner......................................................................................................................................................52
7 Faults - Probable causes - Solutions ......................................................................................................................................53
7.1 Error codes list ...........................................................................................................................................................53
A Appendix - Accessories ...........................................................................................................................................................60
B Appendix - Electrical panel layout...........................................................................................................................................62

3 20068417
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Information and general warnings
1.1 Information about the instruction manual
1.1.1 Introduction
The instruction manual supplied with the burner:
is an integral and essential part of the product and must not
be separated from it; it must therefore be kept carefully for
any necessary consultation and must accompany the burner
even if it is transferred to another owner or user, or to
another system. If the manual is lost or damaged, another
copy must be requested from the Technical Assistance Ser-
vice of the area;
is designed for use by qualified personnel;
offers important indications and instructions relating to the
installation safety, start-up, use and maintenance of the
burner.
Symbols used in the manual
In some parts of the manual you will see triangular DANGER
signs. Pay great attention to these, as they indicate a situation of
potential danger.
1.1.2 General dangers
The dangers can be of 3 levels, as indicated below.
1.1.3 Other symbols
Abbreviations used
Ch. Chapter
Fig. Figure
Page Page
Sec. Section
Tab. Table
1 Information and general warnings
DANGER
Maximum danger level!
This symbol indicates operations which, if not car-
ried out correctly, cause serious injury, death or
long-term health risks.
WARNING
This symbol indicates operations which, if not car-
ried out correctly, may cause serious injury, death
or long-term health risks.
CAUTION
This symbol indicates operations which, if not car-
ried out correctly, may cause damage to the ma-
chine and/or injury to people.
DANGER
DANGER: LIVE COMPONENTS
This symbol indicates operations which, if not car-
ried out correctly, lead to electric shocks with le-
thal consequences.
DANGER: FLAMMABLE MATERIAL
This symbol indicates the presence of flammable
materials.
DANGER: BURNING
This symbol indicates the risks of burns due to
high temperatures.
DANGER: CRUSHING OF LIMBS
This symbol indicates the presence of moving
parts: danger of crushing of limbs.
WARNING: MOVING PARTS
This symbol indicates that you must keep limbs
away from moving mechanical parts; danger of
crushing.
DANGER: EXPLOSION
This symbol signals places where an explosive at-
mosphere may be present. An explosive atmos-
phere is defined as a mixture - under atmospheric
conditions - of air and flammable substances in
the form of gases, vapours, mist or dust in which,
after ignition has occurred, combustion spreads to
the entire unburned mixture.
PERSONAL PROTECTION EQUIPMENT
These symbols indicate the equipment that must
be worn and kept by the operator for protection
against threats against safety and/or health while
at work.
OBLIGATION TO ASSEMBLE THE HOOD AND
ALL THE SAFETY AND PROTECTION DEVIC-
ES
This symbol signals the obligation to reassemble
the hood and all the safety and protection devices
of the burner after any maintenance, cleaning or
checking operations.
ENVIRONMENTAL PROTECTION
This symbol gives indications for the use of the
machine with respect for the environment.
IMPORTANT INFORMATION
This symbol indicates important information that
you must bear in mind.
This symbol indicates a list.

20068417 4
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Information and general warnings
1.1.4 Delivery of the system and the instruction
manual
When the system is delivered, it is important that:
the instruction manual is delivered to the user by the system
manufacturer, with the recommendation to keep it in the
room where the heat generator is to be installed.
The instruction manual shows:
– the serial number of the burner;
– the address and telephone number of the nearest Assis-
tance Centre.
The system supplier must carefully inform the user about:
– the use of the system;
– any further tests that may be required before activating the
system;
– maintenance, and the need to have the system checked at
least once a year by a representative of the manufacturer
or another specialised technician.
To ensure a periodic check, the manufacturer recom-
mends the drawing up of a Maintenance Contract.
1.2 Guarantee and responsibility
The manufacturer guarantees its new products from the installa-
tion date, in accordance with the regulations in force and/or the
sales contract. At the moment of the first start-up, check that the
burner is integral and complete.
In particular, the rights to the guarantee and the responsibility will
no longer be valid, in the event of damage to things or injury to
people, if such damage/injury was due to any of the following
causes:
incorrect installation, start-up, use and maintenance of the
burner;
improper, incorrect or unreasonable use of the burner;
intervention of unqualified personnel;
carrying out of unauthorised modifications on the equipment;
use of the burner with safety devices that are faulty, incor-
rectly applied and/or not working;
installation of untested supplementary components on the
burner;
powering of the burner with unsuitable fuels;
faults in the fuel supply system;
use of the burner even following an error and/or an irregular-
ity;
repairs and/or overhauls incorrectly carried out;
modification of the combustion chamber with inserts that
prevent the regular development of the structurally estab-
lished flame;
insufficient and inappropriate surveillance and care of those
burner components most likely to be subject to wear and
tear;
the use of non-original components, including spare parts,
kits, accessories and optional;
force majeure.
The manufacturer furthermore declines any and every re-
sponsibility for the failure to observe the contents of this
manual.
.........................................................................................
.........................................................................................
.........................................................................................
.........................................................................................
WARNING
Failure to observe the information given in this
manual, operating negligence, incorrect installa-
tion and carrying out of non authorised modifica-
tions will result in the annulment by the
manufacturer of the guarantee that it supplies with
the burner.

5 20068417
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Safety and prevention
2.1 Introduction
The burners have been designed and built in compliance with
current regulations and directives, applying the known technical
rules of safety and envisaging all the potential danger situations.
It is necessary, however, to bear in mind that the imprudent and
clumsy use of the equipment may lead to situations of death risk
for the user or third parties, as well as the damaging of the burner
or other items. Inattention, thoughtlessness and excessive confi-
dence often cause accidents; the same applies to tiredness and
sleepiness.
It is a good idea to remember the following:
The burner must only be used as expressly described. Any
other use should be considered improper and therefore dan-
gerous.
In particular:
it can be applied to boilers operating with water, steam, diather-
mic oil, and to other users expressly named by the manufacturer;
the type and pressure of the fuel, the voltage and frequency of the
electrical power supply, the minimum and maximum deliveries for
which the burner has been regulated, the pressurisation of the
combustion chamber, the dimensions of the combustion chamber
and the room temperature must all be within the values indicated
in the instruction manual.
Modification of the burner to alter its performance and desti-
nations is not allowed.
The burner must be used in exemplary technical safety con-
ditions. Any disturbances that could compromise safety must
be quickly eliminated.
Opening or tampering with the burner components is not
allowed, apart from the parts requiring maintenance.
Only those parts envisaged by the manufacturer can be
replaced.
2.2 Personnel training
The user is the person, body or company that has acquired the
machine and intends to use it for the specific purpose. He is re-
sponsible for the machine and for the training of the people work-
ing around it.
The user:
undertakes to entrust the machine exclusively to suitably
trained and qualified personnel;
undertakes to inform his personnel in a suitable way about
the application and observance of the safety instructions.
With that aim, he undertakes to ensure that everyone knows
the use and safety instructions for his own duties;
Personnel must observe all the danger and caution indica-
tions shown on the machine.
Personnel must not carry out, on their own initiative, opera-
tions or interventions that are not within their province.
Personnel must inform their superiors of every problem or
dangerous situation that may arise.
The assembly of parts of other makes, or any modifications,
can alter the characteristics of the machine and hence com-
promise operating safety. The manufacturer therefore
declines any and every responsibility for any damage that
may be caused by the use of non-original parts.
In addition:
2 Safety and prevention
WARNING
The manufacturer guarantees safety and proper
functioning only if all burner components are intact
and positioned correctly.
the user must take all the measures neces-
sary to prevent unauthorised people gaining
access to the machine
the user must inform the manufacturer if
faults or malfunctioning of the accident pre-
vention systems are noticed, along with any
presumed danger situation
personnel must always use the personal pro-
tective equipment envisaged by legislation
and follow the indications given in this man-
ual

20068417 6
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Technical description of the burner
3.1 Burner designation
3.2 Models available
Tab. A
3 Technical description of the burner
R S 50 E TC FS1 3/400/50 230/50/60
BASIC DESIGNATION
EXTENDED DESIGNATION
MZ
Range : R
Size
Fuel : Natural gas
Light oil
Light oil / Natural gas
Adjustment :
Flame control system :
FS1
FS2
Standard (1 stop every 24h)
Continuous operation (1 stop every 72h)
Electrical supply of the system :
3/400/50
3/230/50
Voltage of auxiliaries :
230/50/60
110/50/60
3N / 400V / 50Hz
3 / 230V / 50Hz
230V / 50-60Hz
110V / 50-60Hz
Heavy oil
E Electronic cam
EV Electronic cam and variable speed (with Inverter)
M Mechanical cam
P Proportional air/gas valve
S
L
LS
N
Head : TC Standard head
TL Long head
Emission : ...
MZ
BLU
MX
Class 1 EN676
Class 2 EN676
Class 3 EN676
Class 3 EN676
3/400-230/50 3N / 400V-230V / 50Hz
Designation Voltage Start-up Code
RS 50/E MZ TC 3 ~ 400 / 230V - 50Hz Direct 3781632
RS 50/E MZ TL 3 ~ 400 / 230V - 50Hz Direct 3781633

7 20068417
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Technical description of the burner
3.3 Burner categories
Tab. B
3.4 Technical data
Tab. C
(1) Reference conditions: Room temperature 20°C - Gas temperature 15°C - Barometric pressure 1013 mbar - Altitude 0 m above sea level.
(2) Gas pressure on the pipe coupling test point 20)(Fig. 5 at page 11) with zero pressure in the combustion chamber and at maximum burner output.
(3) Sound pressure measured in manufacturer's combustion laboratory, with burner operating on test boiler and at maximum rated output. The sound
power is measured with the “Free Field” method, as per EN 15036, and according to an “Accuracy: Category 3” measuring accuracy, as set out in
EN ISO 3746.
(4) Blast tube: short-long.
3.5 Electrical data
Tab. D
Country of destination Gas category
BE I2E(R)
LV I2H
CY, MT I3B/P
BE I3P
LU, PL II2E3B/P
DE II2ELL3B/P
FR II2Er3P
AT, CH, CZ, DK, EE, FI, GR, HU, IS, IT, LT, NO, SE, SI, SK II2H3B/P
ES, GB, IE, PT II2H3P
NL I2L - I2E - I2 (43.46 ÷ 45.3 MJ/m3(0°C))
Model RS 50/E MZ
Output (1) Max. kW
Mcal/h
285 ÷ 630
245 ÷ 542
Min. kW
Mcal/h
80
69
Fuel Natural gas: G20 (methane gas) - G21 - G22 - G23 - G25
Gas pressure at max. output (2) -
Gas: G20/G25
mbar 8.5 / 11.3
Operation – Intermittent (min. 1 stop in 24 hours)
– Two progressive or modulating stages with kit (see ACCESSORIES).
Standard applications Boilers: water, steam, diathermic oil
Ambient temperature °C 0 - 40
Combustion air temperature °C max 60
Noise levels (3) Sound pressure
Sound power dB(A) 72 83
Weight (4) kg 41 - 43
EC Nr. EC-0085AQ0709
Model RS 50/E MZ
Main electrical supply
Control circuit power supply
3 ~ 400 / 230V +/-10% 50 Hz
1N 230V ~ +/-10% 50/60Hz
Fan motor Hz
rpm
V
kW
A
50
2850
230/400
0.65
2.38/1.7
60
3450
260/460
0.65
2.4/1.4
Ignition transformer V1 - V2
I1 - I2
220/240V - 1x15 kV
45 VA - 25 mA
Absorbed electrical power kW max 1.09
Protection level IP 44

20068417 8
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Technical description of the burner
3.6 Maximum dimensions
The dimensions of the burner are shown in Fig. 1.
Bear in mind that inspection of the combustion head requires the
burner to be opened and the rear part drawn back on the guides.
The dimensions of the open burner are indicated by position H.
Tab. E
(1) Blast tube: short-long
3.7 Firing rate
The maximum output is chosen within area A (Fig. 2).
The minimum output must not be lower than the minimum limit
of the diagram.
Fig. 1
D495
mm A B C D(1) EF G H I LM
RS 50/E MZ 476 474 565 240 - 375 152 352 140 800 86 168 1”1/2
WARNING
The firing rate (Fig. 2) was obtained considering a
room temperature of 20°C and an atmospheric
pressure of 1013 mbar (approx. 0 m above sea
level), with the combustion head adjusted as
shown at page 22.
A
Fig. 2
Thermal power
D9090
Combustion chamber
pressure - mbar

9 20068417
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Technical description of the burner
3.7.1 Firing rate on basis of air density
The firing rate of the burner shown in the manual is valid for a
room temperature of 20°C and an altitude of 0m above sea level
(barometric pressure around 1013 mbar).
It may be that a burner has to operate with combustive air at a
higher temperature and/or higher altitudes.
The heating of the air and the increase in altitude produce the
same effect: the expansion of the air volume (i.e. the reduction of
its density).
The delivery of the burner fan remains essentially the same, but
the oxygen per m3of air, and the thrust (discharge head) of the
fan are reduced.
It is therefore important to know if the maximum output requested
from the burner at a determinate combustion chamber pressure
remains within the firing rate of the burner even with the changed
temperature and altitude conditions.
To check it, proceed as follows:
1 find the corrective factor F (relating to the air temperature
and altitude of the system) in the Tab. F.
2 Divide the output Q required from the burner by F to obtain
the equivalent output Qe:
3 In the firing rate of the burner, mark the work point identified
by:
Qe = equivalent output
H1 = pressure in combustion chamber
point A that must remain within the firing rate.
4 Trace a vertical line from point A)(Fig. 3), and find the maxi-
mum pressure H2 of the firing rate.
5 Multiply H2 by F to obtain the maximum lowered pressure
H3 of the firing rate:
If H3 is greater than H1)(Fig. 3), the burner can produce the de-
livery requested.
If H3 is less than H1, it is necessary to reduce the output of the
burner. The reduction in output is accompanied by a reduction in
the combustion chamber pressure:
Qr = reduced output
H1r = reduced pressure
Example, 5% reduction in output:
Qr = Q x 0,95
H1r = H1 x (0,95)2
With the new values - Qr and H1r - repeat steps 2 - 5.
Tab. F
Qe = Q : F (kW)
H3 = H2 x F (mbar)
WARNING
The combustion head should be adjusted in rela-
tion to the equivalent output Qe.
H1r = H1 x ()
Qr
Q
2
Qe kg/h
mbar
Qe kW
mbar
A
H1
H2
H3
D388
Fig. 3
Altitude Average baro-
metric pressure
F
Air temperature °C
m a.s.l. mbar 0 5 10 15 20 25 30 40
0
100
200
300
400
500
600
700
800
900
1000
1200
1400
1600
1800
2000
2400
2800
3200
3600
4000
1013
1000
989
978
966
955
944
932
921
910
898
878
856
836
815
794
755
714
675
635
616
1.087
1.073
1.061
1.050
1.037
1.025
1.013
1.000
0.988
0.977
0.964
0.942
0.919
0.897
0.875
0.852
0.810
0.766
0.724
0.682
0.661
1.068
1.054
1.042
1.031
1.018
1.007
0.995
0.982
0.971
0.959
0.946
0.925
0.902
0.881
0.859
0.837
0.796
0.753
0.711
0.669
0.649
1.049
1.035
1.024
1.013
1.000
0.989
0.977
0.965
0.954
0.942
0.930
0.909
0.886
0.866
0.844
0.822
0.782
0.739
0.699
0.657
0.638
1.031
1.017
1.006
0.995
0.983
0.972
0.960
0.948
0.937
0.926
0.914
0.893
0.871
0.851
0.829
0.808
0.768
0.726
0.687
0.646
0.627
1.013
1.000
0.989
0.978
0.966
0.955
0.944
0.932
0.921
0.910
0.898
0.878
0.856
0.836
0.815
0.794
0.755
0.714
0.675
0.635
0.616
0.996
0.983
0.972
0.962
0.950
0.939
0.928
0.916
0.906
0.895
0.883
0.863
0.842
0.822
0.801
0.781
0.742
0.702
0.664
0.624
0.606
0.980
0.967
0.956
0.946
0.934
0.923
0.913
0.901
0.891
0.880
0.868
0.849
0.828
0.808
0.788
0.768
0.730
0.690
0.653
0.614
0.596
0.948
0.936
0.926
0.916
0.904
0.894
0.884
0.872
0.862
0.852
0.841
0.822
0.801
0.783
0.763
0.743
0.707
0.668
0.632
0.594
0.577

20068417 10
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Technical description of the burner
3.8 Test boiler
The firing rates were obtained in special test boilers, according to
EN 676 regulations.
Fig. 4 indicates the diameter and length of the test combustion
chamber.
Example:
Output 407 kW (350 Mcal/h) - diameter 50 cm, length 1.5 m.
The coupling is ensured when the boiler is EC type-approved; for
boilers or ovens with combustion chambers of very different di-
mensions compared to those shown in the diagram of Fig. 4, pre-
liminary checks are recommended.
3.9 Burner equipment
The burner is supplied complete with:
Gas train flange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . No. 1
Gasket for gas train flange. . . . . . . . . . . . . . . . . . . . . . . . . No. 1
Thermal insulation screen . . . . . . . . . . . . . . . . . . . . . . . . . No. 1
Screws M8 x 25 to fix the flange . . . . . . . . . . . . . . . . . . . . No. 4
Screws M8 x 25 to fix the burner flange to the boiler. . . . . No. 4
Plugs for electrical wiring . . . . . . . . . . . . . . . . . . . . . . . . . No. 4
Instruction manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . No. 1
Spare parts list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . No. 1
Fig. 4
Combustion chamber
m
D497

11 20068417
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Technical description of the burner
3.10 Burner description
1 Combustion head
2 Ignition electrode
3 Screw for combustion head adjustment
4 Pipe coupling
5 Gas servomotor
6 Plug-socket on ionisation probe cable
7 Motor relay
8 1-0 Operation on/off switch
9 Terminal board for electrical wiring
10 Operator panel with LCD display
11 Control box for checking flame and air/fuel ratio
12 Clean contacts relay
13 Filter to protect against radio disturbance
14 Flame inspection window
15 Ignition transformer
16 Cable grommets for electrical wiring (to be carried out by the
installer)
17 Air servomotor
18 Air pressure switch (differential operating type)
19 Slide bars for opening the burner and inspecting the com-
bustion head
20 Gas pressure test point and head fixing screw
21 Air pressure socket
22 Flame sensor probe
23 Air damper
24 Fan air inlet
25 Screw securing fan to pipe coupling
26 Gas input pipe
27 Gas regulator
28 Boiler fixing flange
29 Flame stability disc
30 Bracket for application of output power regulator RWF
19 203 1256
10
9
8
12
7
14 23 17
22
29
28
16
21
24
15
4
2
18
11
30
13
5
27
26
Fig. 5
D8741
A
View from A

20068417 12
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Technical description of the burner
3.11 Control box for the air/fuel ratio (REC 27.100A2)
Important notes
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.
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.
WARNING
To avoid accidents, material or environmental
damage, observe the following instructions!
The control box is a safety device! Avoid opening
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.
Fig. 6
D8266

13 20068417
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Technical description of the burner
Electrical connection of 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 sig-
nal.
– Use a separate cable.
Respect the allowed cable lengths.
The ionisation probe is not protected against the risk of elec-
trocution; it must be protected against any accidental con-
tact.
The grounding of the burner must be in compliance with the
rules in force; the grounding of the boiler alone is not
enough.
Position the ignition electrode and the ionisation probe so
that the ignition spark cannot form an arc on the probe (risk
of electric overcharge).
Technical data
Control box Mains voltage AC 230 V -15 % / +10 %
Mains frequency 50 / 60 Hz ±6 %
Power absorption < 30 W (normal)
Safety class I, with components in compliance with II and III, ac-
cording to DIN EN 60730-1
Load on ‘input’
terminals
F1 unit fuse (internal) 6,3 AT
Main fuse of perm. network (external) Max. 16 AT
Undervoltage
– Safety switch-off from operating position to mains
voltage
– Restart when mains voltage picks up
< AC 186 V
> AC 195 V
Input currents and input voltages
– UeMax
–UeMin
– Iemax
–IeMin
UN +10%
UN -15%
1.5 mA peak
0.7 mA peak
Voltage detection
–On
–Off
AC 180...253 V
< AC 80 V
Load on ‘output’
terminals
Total load on the contacts
– Mains voltage
– Total unit input current (safety circuit)
- Fan motor contactor
- Ignition transformer
- Valve
AC 230 V, 50 / 60 Hz
Max. 5 A
Single contact loading
Fan motor contactor
– Rated voltage
– Nominal current
– Power factor
AC 230 V, 50 / 60 Hz
2A
cos> 0.4
Alarm output
– Rated voltage
– Nominal current
– Power factor
AC 230 V, 50 / 60 Hz
1A
cos> 0.4
Ignition transformer
– Rated voltage
– Nominal current
– Power factor
AC 230 V, 50 / 60 Hz
2A
cos> 0.2
Fuel valve
– Rated voltage
– Nominal current
– Power factor
AC 230 V, 50 / 60 Hz
2A
cos> 0.4
Display operation
– Rated voltage
– Nominal current
– Power factor
AC 230 V, 50 / 60 Hz
0,5A
cos> 0.4

20068417 14
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Technical description of the burner
Tab. G
Cable lengths – Main line AC 230 V
– Display, BCI
– Load control (LR) X5-03
– External reset button
– Safety valve (SV)
– Load output
– Fuel valve
– Pilot valve
– Ignition transformer
– Other lines
Max. 100 m (100 pF / m)
For installation under the casing of the burner or in
the control panel max. 3 m (100 pF / m)
Max. 20 m (100 pF/m)
Max 20 m (100 pF/m)
Max 20 m (100 pF/m)
Max. 10 m (100 pF/m)
Max. 3 m (100 pF/m)
Max. 3 m (100 pF/m)
Max. 3 m (100 pF/m)
Max. 3 m (100 pF/m)
Cross-sections of
the power supply
lines
They should be sized for rated currents as per the pri-
mary external fuse and the fuse of the internal unit.
– Min. cross-section
– Fuses used inside the control box F1
(max. 6,3 AT)
0,75 mm²
6,3 AT DIN EN 60127 2 / 5
Environmental
conditions
Storage
– Climatic conditions
– Mechanical conditions
– Temperature range
– Humidity
DIN EN 60721-3-1
Class 1K3
Class 1M2
-20 ... +60 °C
< 95% RH
Transport
– Climatic conditions
– Mechanical conditions
– Temperature range
– Humidity
DIN EN 60721-3-2
Class 2K2
Class 2M2
-30 ... +60 °C
< 95% RH
Operation
– Climatic conditions
– Mechanical conditions
– Temperature range
– Humidity
DIN EN 60721-3-3
Class 3K3
Class 3M3
-20 ... +60 °C
< 95% RH
WARNING
Condensation, formation of ice and the entrance
of water are not permitted!

15 20068417
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Technical description of the burner
3.12 Operation sequence of the burner
t1 TSA1
5) 6)
27s 5s
13)
30s 0.6s
Pa
P
P
P
P
Phase number
INPUT SIGNALS
Thermostat/pressure switch
OUTPUT SIGNALS
Thermostat/pressure switch
Ionisation probe ION
Air pressure switch PA
Min. gas pressure switch.
Min. gas pressure switch.
Gas pressure switch for
PGVP leak detection
Alternative to the FS
safety control
Fan motor MV
Transformer of the
VS safety valve
Fuel valve V1
Fuel valve V2
Pilot valve VP
Lock-out signal
indicator TL
SERVOMOTORS
Air Fuel
90°
Nominal load
Post-purging pos.
Ignition load
Low flame
Pos. without load
0°
S8870 Fig. 7
Checking of
sealShutdown
Operation
Start up
Timer - Resolution - Ratio
Timer 1 (parameters)
Timer 2 (parameters)
Timer 3 = max. phase time
Input signals
PGmin
PGMin
Max. gas pressure switch
PGMax
CPI seal
TA ignition
90°
Nominal load
Post-purging pos.
Ignition load
Low flame
Pos. without load
0°
RAST plug
X3-04 Pin 1/2
PIN number
X5-03 Pin 1/4
X10-05 Pin 2 Pin 3/4
X10-06 Pin 1/2
X3-02 Pin 1/2
X5-01 Pin 2/3
X5-01 Pin 2/3
X5-02 Pin 2/3
X9-04 Pin 2/3
X5-02 Pin 2/3
X3-05 Pin 1
X4-02 Pin 2/3
X6-03 Pin 2/3
X8-02 Pin 1/3
X7-01 Pin 2/3
X7-02 Pin 2/3
X3-05 Pin 2
RAST plug
PIN number
X54
X53
ON Signal
OFF Signal
Any signal is allowed

20068417 16
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Technical description of the burner
3.12.1 List of phases
3.13 Operator panel operation
The control box REC 27.100A2 is directly connected to the oper-
ator panel (Fig. 8).
The buttons allow you to programme the operation and diagnos-
tics menus.
The burner management system is visualised on the LCD display
(Fig. 9). To simplify the diagnostics, the display shows the oper-
ating status, type of problem, and when the problem arose.
3.13.1 Symbols description on the display
The display brightness can be regulated from 0 ... 100% with pa-
rameter 126.
Phase Description
Ph00 Lockout phase
Ph02 Safety phase
Ph10 Closing paused
Ph12 Standby
Ph22 Fan motor (MV) = ON
Safety valve (VS) = ON
Ph24 The burner moves to the pre-purging position
Ph30 Pre-purging time
Ph36 The burner moves to the ignition position
Ph38 Ignition phase (TA) = ON
Ph39 Min. gas pressure switch test (PGmin.)
Ph40 Fuel valve (V) = ON
Ph42 Ignition (TA) = OFF
Ph44 t44 = interval time 1
Ph60 Operation
Ph62 The burner moves to the switching off position
Ph70 t13 = post-combustion time
Ph72 The burner moves to the post-purging position
Ph74 t8 = post-purging time
Ph78 t3 = post-purging time
Ph80 Emptying time (valve leak detection)
Ph81 Atmospheric test time (valve leak detection)
Ph82 Filling time (valve leak detection)
Ph83 Pressure test time (valve leak detection)
Ph90 Standby time due to lack of gas
Phase Description
WARNING
Observe the procedures and adjustments
shown below.
All interventions (assembly and installation
operations, assistance, etc.) must be carried
out by qualified personnel.
If the display and operator panel are dirty,
clean them with a dry cloth.
Protect the panel from excessive tempera-
tures and liquids.
D9001 Fig. 8
Lock-out lamp
Flame presence
Valve powered
Ignition transformer
Fan motor powered
Pre-heater active
Heat request
Info Mode active
Service Mode active
Closure of servomotors
Opening of servomotors
Measurement unit
Lockout
Parameters Mode active
only for light oil burners
Vhmin s
D9000
powered
Fig. 9

17 20068417
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Technical description of the burner
3.13.2 Buttons description
Tab. H
Button Button Function
Button F
To regulate the fuel servomotor
(keep pressed and adjust the value by pressing or )
Button A
To regulate the servomotor air
(keep pressed and adjust the value by pressing or )
Button A and F
VSD Function
To modify the parameter for setting the P mode
(simultaneously press and plus or
Button Info and
Enter
•Enter in Parameters Mode
•Reset in the event of a lockout
• Access to a lower level of the menu
• To navigate in Service or Info Mode and allows:
– the selection of the parameter (flashing symbol) (press for <1 s)
– access to a lower level of the menu (press from 1...3 s)
– access to a higher level of the menu (press from 3...8 s)
– access to another Mode (press for > 8 s)
Button -
Reduction of the value
– Access to a lower point of the modulation curve
– Scrolling of the parameter list
Button +
Increase of the value
– Access to a higher point of the modulation curve
– Scrolling of the parameter list
Buttons - and +
Quit function (ESC)
(press and simultaneously)
– Does not confirm the value
– Access to a higher level of the menu
F
F
A
A
VSD
AF
F
A
/reset
ESC

20068417 18
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Technical description of the burner
3.14 Servomotors (SQN13...)
Introduction
The servomotors that equip the burners of the RS range work di-
rectly on the air damper and the gas butterfly valve, without me-
chanical leverages but via the interposition of an elastic coupling.
They are commanded by the control box, which constantly
checks their position by means of a return signal from the optic
sensor inside the servomotor.
Important notes
All interventions (assembly and installation operations,
assistance, etc.) must be carried out by qualified personnel.
Before modifying the wiring in the servomotor connection
area, fully disconnect the burner control device from the
power supply (omnipolar separation)..
To avoid the risk of electrocution, protect the connection ter-
minals in a suitable manner and correctly fix the cover.
In the event of assembly, installation, maintenance, etc... it is
necessary to check that the wiring and the parameterisation
are in order.
Falls and collisions can negatively affect the safety func-
tions. In this case, the unit must not be operated, even if it
displays no evident damage.
Installation notes
Check the relevant national safety standards are respected.
The connection between the actuator command shaft and
the control element must be rigid, without any mechanical
play.
The tightening torque for the fixing screws should be 1.5
Nm. It is recommended that this value is not exceeded to
prevent damaging the servomotor.
To avoid an excessive load on the bearings due to rigid
hubs, the use of compensation clutches without any
mechanical play is recommended (e.g. metal bellows-type
clutches).
It is advisable to oversize the drive shaft in relation to the
rated torque of the actuator.
The static torque is reduced when the electrical supply of the
actuator is switched off.
Arrange the H.V. ignition cables separately, as far as possi-
ble from the control box and the other cables.
Technical data
Tab. I
WARNING
To avoid accidents, material or environmental
damage, observe the following instructions!
Avoid opening, modifying or forcing the servo-
motor. The servomotor is equipped with a system
of optical feedback.
Power supply AC / DC 24 V ± 20% (load inter-
face)
Safety class EN 60730 part 1-14
Power absorption Max. 7.5 W
Angle adjustment, usable
range Max. 90°
Degree of protection IP40
Work of field 0-90°
Opening time 0-90° 5 sec.
Direction of rotation Anticlockwise
Torque operating 0.7 Nm
Torque off 0.4 Nm
Cable length 1.2 m
Radial load on the bearing 30 N
Axial load on the bearings Max. 5 N
Weight About 0.3 kg
Connecting cable RAST2.5
Environmental conditions:
Operation
Climatic conditions
Mechanical conditions
Temperature range
Humidity
DIN EN 60721-3-3
Class 3K3
Class 3M3
-10 ... +60 °C
< 95% RH
WARNING
Condensation, formation of ice and the entrance
of water are not permitted!
Fig. 10
D8083