Riello GAS 7 P/M Quick start guide

Installation, use and maintenance instructions
2915245 (5) - 05/2018
Forced draught gas burner
Progressive two-stage or modulating operation
CODE MODEL TYPE
3753781 GAS 7 P/M 537 T80
GB

Declaration of conformity in accordance with ISO / IEC 17050-1
Manufacturer: RIELLO S.p.A.
Address: Via Pilade Riello, 7
37045 Legnago (VR)
Product: Forced draught gas burner
Model: GAS 7 P/M
These products are in compliance with the following Technical Standards:
EN 676
EN 12100
and according to the European Directives:
MD 2006/42/EC Machine Directive
LVD 2014/35/UE Low Voltage Directive
EMC 2014/30/UE Electromagnetic Compatibility
The quality is guaranteed by a quality and management system certified in accordance with UNI EN ISO 9001.
Mr. U. Ferretti Mr. F. Comencini

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TECHNICAL DATA
ELECTRICAL DATA
BURNER DESCRIPTION
BURNER EQUIPMENT
Thermal power 400 - 1760 kW - 344.000 - 1.513.600 kcal/h
Operation • Two stages progressive
• Modulating (kit with controller available upon request)
Fuel Natural gas Pci 8 - 10 kWh/m3= 7000 - 8600 kcal/m3
Minimum gas pressure For maximum output 14.5 mbar are needed measured at the coupling with nil pressure in the combustion chamber and gas with calorific value of 8600 kcal/
m3
Maximum gas pressure 150 mbar
Electrical supply Three-phase 220V +10% -10% ~ 60Hz without neutral
380V +10% -10% ~ 60Hz with neutral
Motor 10A / 230V - 5.8A / 400V
Ignition transformer Primary: 1.8A / 220V - Secondary: 1 x 8 kV - 30 mA
Absorbed electrical power 4.1 kW
Quantity Burner accessories
1 Flange
1Gasket
8Screws
1 Flange gasket
1 Servomotor controlling air and gas
2 Adjustment cam
3 Power controller (for modulating to be required
separately)
4 Control box re-set button
5 Servomotor connection
6 Fair leads
7 Wiring terminal block
8 Re-set push-button of the motor overload relay
9 Air pressure switch
10 Gas pressure test-point
Fig. 1
D2206

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MAXIMUM DIMENSIONS
COMBUSTION CHAMBER PRESSURE - MAXIMUM OUTPUT
(in compliance with DIN 4788)
Min. output: 400 kW - 344.000 kcal/h.
Boiler front-plate
drilling
*Length available with special blast tube to be separately required.
Burner
230
230
230 M12
D1785
D2201
D2202

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MINIMUM GAS PRESSURE - OUTPUT
Pressure: detected at the pressure test-point 10) (fig. 1) with nil mbar into the combustion chamber.
Should the combustion chamber be pressurized, the pressure necessary will be that of the graph plus
the pressurization value.
Example: to obtain 1250 kW it is necessary a gas pressure of 12 mbar and the combustion head set as indicated
at page 8.
If the combustion chamber is pressurized at 2 mbar, the pressure detected at the test-point 9) is: 12 +
2 = 14 mbar.
If this value is too high, for very low gas pipework pressures, the gas gear 6) (page 8) could be more
open.
Do not decrease the pressure at the coupling under the values shown in the diagram.
Output: the maximum value is obtainable with gas Pci 8600 kcal/m3.
CORRELATION BETWEEN GAS PRESSURE AND BURNER OUTPUT
D2203

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FIXING TO THE BOILER
GAS SUPPLY
1 - Gas pipe line
2 - Cock valve
3 - Filter
4 - Pressure stabilizer
5 - Pressure test-point
6 - Minimal gas pressure switch
7 - Safety valve
8 - Adjustment valve
9 - Adjusting throttle valve
10 - Burner
11 - Gas leak control device
Separate the blast tube from the burner body
by loosening the screws 7) and 3), fix the
blast tube to the boiler front plate 5) using the
gasket 6) provided.
Insert the burner on the holding bars 4) and
fasten the screws 7) and 3).
The combustion head adjustment should be
carried out as follows:
Loosen the screws 2) unhook the tension
rod of the air damper 1) remove the
connecting lead of the servomotor, withdraw
the group A) from the group B).
After the setting, re-assemble and verify that
the tension rod of the air damper was locked.
D2178
D2179
Supplied
upon request To be carried out by the installer

5 2915245
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BURNER ELECTRICAL WIRING
(carried out y the factory)
Key to layout
CMV Motor contactor
LFL... Control box
MB Burner terminal strip
MV Fan motor
PA Air pressure switch
RT Thermal cut-out
SM Servomotor
SO Ionisation probe
SP Plug-socket
TA Ignition transformer
TB Burner ground
20152071

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ELECTRICAL CONNECTIONS TO THE WIRING TERMINAL BLOCK
(to be carried out by the installer)
NOTICE
- The electric wiring carried out by the installer must be in compliance with the rules in force in the Country.
- Leads minimal section 1 mm2.
- Adjustment for the motor thermal relay:
• at the beginning of the scale for 380 V;
• at the end of the scale for 220 V.
- Burners with non-stop operation.
For safety reasons, this type of burner must be stopped every 24 hours of operation, by means of an hours-
counter to be connected in series with the adjustment devices.
Key to layout
BP - Pressure probe
BT - Temperature probe
MB - Burner terminal strip
PC - Check pressure switch
PG - Min. gas pressure switch
RWF50 - Power controller
TR - High-low mode load remote control sys-
tem: controls operating stages 1 and 2
TL - Load limit remote control system: shuts
down the burner when the boiler temper-
ature or pressure reaches the preset
value.
TS - Safety load control system: operates
when TL is faulty
VR - Adjustment valve
VS - Safety valve
20152143

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FIXING OF THE ELECTRICAL WIRES
All the electrical wires, which are to be connected to the terminal block 7) (fig. 1) shall pass through the fair
leads 6) (fig. 1) as per this scheme.
1- Three phase supply : fair lead Pg 21
2- Single phase supply : fair lead Pg 13.5
3- Adjustment thermostat : fair lead Pg 13.5
4- Safety thermostat : fair lead Pg 13.5
5- Gas train : fair lead Pg 13.5, sheath ø 13
6-2nd stage thermostat : fair lead Pg 13.5 (probe for modulating version)
7- Pre-sheared holes : fair lead Pg 13.5 (for power controller - modulating version)
8- Pre-sheared holes
Further prospective signals or controls can be connected to the burner wiring terminal board by removing the metal
weldnuts from the pre-sheared holes and inserting a commun fair lead for the passage and the clamping of the
leads.
NOTES
- Do not exchange the neutral wire with the phase (avoid the plug-pin connection).
- Carry out a safe earth connection.
- Check the stop of the burner, by opening the boiler thermostat and the burner lock-out, by disconnecting the lead
from the flame probe.
WARNING
When closing the burner on its slide-bars, pull towards the outside the high voltage cable and the cable of the
flame detection probe, till to little tension.
D2184

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BURNER START-UP CYCLE
Air-purge: loosen the screw placed on the minimal gas pressure switch mounted on the gas train.
AIR PRESSURE SWITCH
The air pressure switch setting shall be carried out after having set all other
adjustments of the burner and the air pressure switch shall be at its lowest
set-point.
When the burner is operating, increase the adjustment pressure by turning
- slowly - clockwise the knob till reaching the burner lock-out.
Thereafter, turn the knob anticlockwise for 1 mbar and repeat the burner
start-up for checking the regularity: if lock-out intervenes turn the knob an-
ticlockwise for 0.5 mbar.
CAUTION:
do not turn the ionization probe, maintain the drawing position; should it be close to the ignition electrode, damage
may occur to the control box amplifier.
Screw
Plug for pressure measure
Pressure switch
S7506
1 ÷ 10
mbar
Adjustment knob
S7507
D2206

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COMBUSTION HEAD ADJUSTMENT
Two separate adjustments have to be made: air and gas.
These adjustments can be carried out when the burner is still open, during the installation (see page 2 - Fixing to
the boiler).
Air setting
Loosen the two screws 1) and move the internal part of
the combustion head 2) so that its rear edge 3) is coin-
cident with the desired set-point on the plate 4). Tighten
the screws 1).
Gas setting
Loosen the screw 5), move the ring 6) so that the point-
er 7) is coincident with the desired set-point 8). Tighten
the screw 5).
Attention:
the set-point number is the same for air and gas setting
and is given by the following diagram.
Example:
the burner is installed on a boiler of 500 kW, assuming
an efficiency of 90% the burner output should be 560 kW.
From the diagram it can be seen that the air and gas settings for this rating should be no. 5.
D2204
D2205

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ADJUSTMENT OF THE SERVOMOTOR
The servomotor controls the air damper and the gas
throttle valve.
It is provided with three adjustable cams controlling
the related change-over switches.
1) Red cam
2) Blue cam
3) Orange cam
4) Pointer
5) Servomotor releasing lever
Red cam: it controls the max. stroke, generally it is
positioned on 130°.
Blue cam: it controls the min. stroke and remains
always positioned on 0°, in this way,
when the burner is off the air damper is
totally closed.
Orange cam:it controls the minimal modulating pow-
er. It is set by the factory on 30°: normal-
ly this position is the most suitable for the
first ignition.
Thereafterthe installermay vary this set-
ting accordingly with the installation re-
quirements.
6) Cam with adjustable profile
7) Adjustable profile
8) Fastening screws
9) Adjusting screws
10) Throttle valve control sector
11) Tension rod
12) Gas adjustment shutter
54
1
23

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COMBUSTION CHECKS
For the combustion adjustment we suggest to proceed in this way:
• Let the burner starts and after the flame ignites at the minimum output, disconnect the servomotor by opening
the connection 5)(page 1) placed on the panel.
• Thereafter proceed successively to the adjustment of the maximum, minimal outputs and to the intermediate
output.
MAXIMUM OUTPUT SETTING
Gas
• Disjoin the cam with adjustable profile 6) from the servomotor by re-setting the button 5).
• Turn manually clockwise the cam 6) till to reach the position of 130° (on the edge of the servomotor) in corris-
pondence of the pointer 4). In this way the gas throttle valve 12) is at the max. opening 90°.
• Join again the cam with adjustable profile 6) to the servomotor by pushing the button 5).
Now set the gas rate by acting on the gas setting valve.
Air
• Move the adjustable profile 7) of the cam by gradually acting on the screws 9).
MINIMAL OUTPUT SETTING
Gas
• Disjoin the cam with adjustable profile 6) by means of the button 5).
• Turn manually anticlockwise the cam till to reach the position of 30°.
• Lock it again and measure the gas rate.
If a different minimal output is desired, set free the cam with adjustable profile and turn it anticlockwise; for a
higher output turn it clockwise. When the minimal value is satisfying, set on the cam 3) the opening value signed
on the pointer 4).
Air
• Vary the profile of the cam 7) by gradually acting on the screws 9).
Be careful to not modify the part of profile controlling the air shutter at the maximum output, previously set.
INTERMEDIATE OUTPUTS SETTING
Gas
No setting is required.
Air
It is carry out by acting on the screws 9) of the cam profile, being careful to not move those for the minimum and
maximum outputs.
When the combustion setting is ended re-connect the electrical wiring of the servomotor by plugging the connector
5) (page 1); then lock the screws 9) by means of the cross-screws 8).

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RATIO BETWEEN THE MINIMUM AND MAXIMUM OUTPUT
For a better explanation we suppose to have a burner with an adjustable output between the range 25 - 100.
The ratio between the minimum and maximum output is generally included between 1 : 4 (25 - 100) and 1 : 3 (25
- 75); our burners leave the factory set for these ratio.
If the ratio should be reduced at 1 : 2 (25 - 50 or 50 - 100) it is advisable to re-adjust the tension rods for the air and
gas and the controlling sector of the gas throttle valve.
CONTROL OF THE GAS THROTTLE VALVE
The tension rod 11) moving the control sector of the throttle valve
is positioned - by the factory - on the hole marked 90° (90° is the
moving angle of the throttle valve when the cam with adjustable
profile 6) covers the complete angle of 130°).
When the ratio between the minimum and maximum output is
approximately 1 : 2, the tension rod shall be positioned on the hole
marked 60° (60° is the moving angle of the throttle valve when the
cam covers 130°).
If the ratio 1 : 2 is in the lower outputs range (25 - 50) the change
from 90° to 60° of the tension rod will be sufficient. Should this ratio
be in higher range (50 - 100) in this case, further to position the
tension rod on 60° it shall be shortened.
Proceed as follows:
- Disjoint the articulation from the control sector.
- Screw down the tension rod on the extension.
- Reassemble the articulation on the control sector.
In this way the gas throttle valve - servomotor at 0° - is partially
open.
The shortening of the tension rod shall permit the gas flow without
setting the 3rd cam of the servomotor too forward, because in this
way the turn of the cam with adjustable profile would be limited.
CONTROL OF THE AIR DAMPER
The lenght of the tension rod 13) adjusting the air damper can be
varied too.
If the air damper is moving, during the operation, into a reduced
angle (ratio 1 : 2 lower outputs range) it is necessary to extend the
tension rod.
In this way the cam profile is not too much bent.
When the burner is off proceed in this way:
- Disjoint the articulation 14) of the tension rod 13) from the lever
15).
- Extend the tension rod.
- Manually position the servomotor on 0°.
- Join the tension rod to the lever.
- Move the cam profile till the pointer placed on the air damper
shaft is at 0°.
The data of thermal output and combustion head gas
pressure are related to full open (90°) gas butterfly valve.
Throttle valve
control sector
D2188
D2189
WARNING
D2190

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COMBUSTION CHECKS
CO2
It is advisable to not exceed 10% of CO2(gas with calorific value of 8600 kcal/m3), in order to avoid the risk that
small changes of the adjustments due, for instance, at draught variation, may cause combustion with insufficient
air and consequently formation of CO.
CO
For safety reason the value of 0.1% (one thousand p.p.m.) must not be exceeded.
IONIZATION CURRENT
The minimum current necessary for the control box operation is 6 µA.
The burner normally supplies a higher current value, so that no check is needed.
However, if a measurement of the ionization current is required, it is necessary to disconnect the probe lead and
insert a d.c. microamperometer.
MOTOR LOCK-OUT
This is caused by the terminal protector relay, in case of overloading, or by the lacking of the phase.
To clear, pushdown the appropriate knob, after having removed the protective cover.
BURNER START-UP
If during operation the flame shuts off, lock-out occurs within 1 sec.
+-
Lead Probe
S7511
D2191

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BURNER STARTING DIFFICULTIES AND
THEIR CAUSES
The symbol, visible on the reading disc of the pointer,
shows the kind of problem.
The control box does not start at the thermostats
closing, because of:
- lack of gas;
- the gas pressure switch does not close the contact:
bad set;
- the air pressure switch changed over in operation
position;
- the control box fuse is broken;
- the servomotor does not totally change over the
closing circuit in being between the terminals 11 and
8 of the control box.
Stop at the start-up, because of:
- the servomotor does not change over the max.
opening circuit in being between the terminals 9 and
8 of the control box.
 Lock-out
The air pressure switch does not change over, because
of:
- defective contact;
- insufficient pressure of the air.
 Lock-out
Unperfect operation of the flame detecting circuit,
because of:
- probe to earth;
- defective internal amplifier.
 Stop during pre-purge phase, because of:
The servomotor does not change over the minimal
opening circuit in being between the terminals 10 and 8
of the control box.
 Lock-out due to flame signal lack; if:
- the ionisation probe is not inside of the flame;
- the probe connection to the control box is
disconnected;
- the ionization current is insufficient (min. 6 µA).
Lock-out during operation due to:
- flame signal lack;
- no air pressure.
NOTICE
- If lock-out occurs between the start-up and the pre-
ignition phase without that a symbol comes out, the
cause is the flame simulation.
- If the burner repeats continuously the start-up cycle
without lock-out occurring, this is due to the
“oscillation” of the gas pressure switch caused by a
setting very near to the gas network pressure,
therefore the pressure decreasing at the burner start-
up is sufficient to actuate the gas pressure switch
causing a new start-up.
SAFETY TEST - WITH GAS BALL VALVE CLOSED
It is fundamental to ensure the correct execution of the
electrical connections between the gas solenoid valves
and the burner to perform safely the commissioning.
For this purpose, after checking that the connections
have been carried out in accordance with the burner's
electrical diagrams, an ignition cycle with closed gas
ball valve -dry test- must be performed.
1 The manual ball gas valve must be closed
2 The electrical contacts of the burner limit switch
need to be closed
3 Ensures closed the contact of the low gas pressure
switch
4 Make a trial for burner ignition
The start-up cycle must be as follows:
– Starting the fan for pre-ventilation
– Performing the gas valve seal control, if provided
– Completion of pre-ventilation
– Arrival of the ignition point
– Power supply of the ignition transformer
– Electrical Supply of solenoid gas valves
Since the manual gas ball valve is closed, the burner
will not light up and its control box will go to a safety
lockout condition.
The actual electrical supply of the solenoid gas valves
can be verified by inserting a tester. Some valves are
equipped with light signals (or close/open position
indicator) that turn on at the same time as their power
supply.
SAFETY COMPONENTS
The safety components must be replaced at the end of
their life cycle indicated in the table. The specified life
cycles do not refer to the warranty terms indicated in the
delivery or payment conditions.
IF THE ELECTRICAL SUPPLY OF THE GAS
VALVES OCCURS AT UNEXPECTED TIMES, DO
NOT OPEN MANUAL GAS BALL VALVE, SWITCH
OFF POWER LINE; CHECK THE WIRES;
CORRECT THE ERRORS AND REPEAT THE
COMPLETE TEST.
Safety component Life cycle
Flame control 10 years or 250,000
operation cycles
Flame sensor 10 years or 250,000
operation cycles
Gas valves (solenoid) 10 years or 250,000
operation cycles
Pressure switches 10 years or 250,000
operation cycles
Pressure adjuster 15 years
Servomotor (electronic
cam) (if present) 10 years or 250,000 operation cycles
Oil valve (solenoid) (if
present) 10 years or 250,000 operation cycles
Oil regulator (if present) 10 years or 250,000
operation cycles
Oil pipes/ couplings
(metallic) (if present) 10 years
Flexible hoses (if
present) 5 years or 30,000 pressurised cycles
Fan impeller 10 years or 500,000 start-ups
WARNING

Subject to modifications
RIELLO S.p.A.
I-37045 Legnago (VR)
Tel.: [phone]
http:// www.riello.it
http:// www.riello.com