Riello GAS 3 Quick start guide

Installation, use and maintenance instructions
2915858 (3) - 03/2014
Forced draught gas burners
Code Model Type
3751960 GAS 3 519T55
3751961 GAS 3 519T55

5858
1
DECLARATION
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 3
These products are in compliance with the following Technical Standards:
EN 676
EN 292
and according to the European Directives:
MD 2006/42/EC Machine Directive
LVD 2006/95/EC Low Voltage Directive
EMC 2004/108/EC Electromagnetic Compatibility
The quality is guaranteed by a quality and management system certified in accordance with UNI EN ISO
9001.
Legnago, 10.10.2013 Executive Director
RIELLO S.p.A. - Burner Department
Mr. G. Conticini
Research & Development Director
RIELLO S.p.A. - Burner Department
Mr. R. Cattaneo

5858 2
TECHNICAL DATA
BURNER DESCRIPTION
STANDARD EQUIPMENT
OVERALL DIMENSIONS
Thermal output 150 ÷ 350 kW - 130,000 ÷ 300,000 kcal/h
Fuel Natural gas Pci 8 - 10 kWh/m3= 7000 - 8600 kcal/m3
Minimum gas pressure For maximum output 11.1 mbar are needed measured at the coupling with nil pressure in the combustion chamber and gas with calorific val-
ue of 8600 kcal/m3
Maximum gas pressure 35 mbar
Electrical supply Single phase 230 V ±10% ~ 50Hz
Motor 2 A / 230 V
Capacitor 450V - 6.3µF
Ignition transformer Primary: 2A/230V - Secondary: 1 x 9 kV - 33 mA
Absorbed electrical power 0.4 kW
Quantity Description
1 Flange
1 Gasket
8Screws
1 Flange gasket
Fig. 1
1- Air shutter control
2- Air shutter lock-out
3- Control box reset button
4- Fair leads
5- Wiring terminal block
6- Over pressure switch (2)
7- Air pressure switch (1)
8- Gas pressure test-point
* Long combustion head.

5858
3
COMBUSTION CHAMBER PRESSURE - OUTPUT
MINIMUM GAS PRESSURE - OUTPUT
Pressure: Detected at the pressure test-point 8) (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 270 kW it is necessary a gas pressure of 8 mbar and the combustion head set as
indicated at page 9. If the combustion chamber is pressurized at 2 mbar, the pressure detected at
the test-point 8) is: 8 + 2 = 10 mbar.
If this value is too high, for very low gas pipework pressures, the gas gear 6) (page 9) 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.

5858 4
FIXING TO THE BOILER
Separate the combustion head from the
burner body by loosening the screws 1)
and 2) and withdrawing the group A) from
the holding bars 3). Fix the group B) to the
boiler front plate 4) using the gasket 5) pro-
vided as accessory.
GAS DISTRIBUTORS
GAS SUPPLY
Please refer to Appliance Technical Instruction for Gas train details.
LPG DISTRIBUTOR
NATURAL GAS DISTRIBUTOR

5858
5
BURNER ELECTRICAL WIRING
(carried out by the factory)
KEY TO LAYOUT
P1 Air pressure switch
P2 Over pressure switch
CCapacitor
F1 RFI Suppressor
K1 Relay
MB Burner terminal strip
MV Fan motor
RMG Control box
SO Ionisation probe
TA Ignition transformer
TB Burner earth
ATTENTION
In the case of phase-phase feed, a bridge must be fitted on the control box terminal board between terminal 6
and the earth terminal.
WIRING TERMINAL STRIP (SEE PAG. 6)
2565

5858 6
ELECTRICAL CONNECTIONS TO THE WIRING TERMINAL STRIP
(to be carried out by the installer)
Warning
Connect gas valves to terminals 10-11-12 only, exactly as shown on the diagram.
KEY TO LAYOUT
MB Terminal strip
CPI Valve position switch
HRemote lock out signal
TB Burner earth
TL Limit load control system
TS Safety load control system
VA Ignition valve
VR Adjusment valve
VS Safety valve
2566

5858
7
FIXING OF THE ELECTRICAL WIRES
All the electrical wires, which are to be connected to the terminal block 5) (fig. 1) shall pass through the fair
leads 4) (fig. 1) as for this scheme.
1- Single phase supply: fair lead Pg 13.5
2- Adjustment thermostat: fair lead Pg 13.5
3- Safety thermostat: fair lead Pg 13.5
4 - 5 - 6 - 7 - 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.

5858 8
START-UP
For Gas train settings, please refer to Appliance Technical Instructions.
AIR PRESSURE SWITCH “1”
The air pressure switch is set after adjustment have been made. Begin with the switch at the lowest setting. With
the burner working at the minimum output, adjust the dial clockwise, increasing its value until the burner locks
out. Now reduce the value by one set point, turning the dial anti-clockwise.
Check for reliable burner operation. If the burner locks out, reduce the value by a further set point.
OVER PRESSURE SWITCH “2”
The over pressure switch must be set after all other adjustments have been made. its purpose is to cause the
burner to shut down if the combustion chamber pressure increases above normal operational values.
Begin with the switch at the highest setting, with the burner working at the maximum output, adjust the dial anti-
clockwise, decreasing its value until the burner shuts down. Now increase the value by one set point and re-start
the burner. If the burner shuts down due to the pressure surge in the combustion chamber caused by the ignition
gas, check that the start gas rate is less than 25% of the main gas rate. If it is, increase the value on the over
pressure switch by a further half a set point and repeat the test.
NOTE
To comply with the Appliance Standard PREN 1020, the CO value must not exceed 0.1% under normal opera-
tional conditions.
CAUTION
Do not turn the ionization probe, maintain the drawing position; should it be close to the ignition electrode, dam-
age may occur to the control box amplifier.
The right positions of the ionisation probe and of the ignition electrode (as shown in the drawing) is obtainable
by coinciding their insulators planes with sloping planes of the fastening support.
Probe position Ignition electrode position

5858
9
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 4 - 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 coincident 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 pointer 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 260 kW, assuming an efficiency of 90% the burner output should be 290
kW.
From the diagram it can be seen that the air and gas settings for this rating should be no. 5.
Burner output
Set-point number = for air and gas

5858 10
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 con-
sequently formation of CO.
CO
For safety reason the value of 93 p.p.m. must not be exceeded under normal operating conditions.
IONIZATION CURRENT
The minimum current necessary for the control box operation is 3 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.
BURNER START-UP
If during operation the flame shuts off, lock-out occurs within 1 sec.
Lead Probe
Normal Lock-out because no ignition
Thermostat
Motor
Ignition transformer
Ignition valve
Ignition flame
Safety + adjust. valve
2 s 40 s 10 s 2 s 40 s 3 s max.
Operation flame
Lock-out
D1799

5858
11
BURNER STARTING DIFFICULTIES AND THEIR CAUSES
1. The burner goes through the purge period normally, the flame ignites, but the burner goes to lock-out, within two
seconds after the ignition if:
- the ionization probe is earthed or not in contact with theflame, or its wiring to the control box is broken, or there
is a fault on its insulation to earth;
- the ionization current is weak (lower than 3 µA).
2. The burner goes to lock-out, after the purge period, because the flame does not ignite; the causes may be:
- the valve is passing too little gas (Low pressure in the gas pipework);
- the valve is defective;
- the pipe has not been purged from the air;
- the ignition arc is irregular or has failed.
3. The burner does not pass through the pre-purge period and the control box goes to lock-out:
- air pressure switch failure;
- flame simulation exists (or the flame really lights).
4. The burner does not start at the thermostat closing, because of:
- the fuse of the control box is broken.
OPERATING FAULTS
Lock-out may occur, because of: - Flame failure.
- Ionization probe earthed.
- Air pressure switch failure

5858 12
BURNER STARTING DIFFICULTIES AND THEIR CAUSES
Signal Problem Possible cause Recommended remedy
2 blinks Once the pre-purg-
ingphaseandsafety
time have passed,
the burner goes into
lockout without the
appearance of the
flame
1 - The operation solenoid lets little gas.
through Increase
2 - One of the two solenoid valves does
not open. Replace
3 - Gas pressure too low. . . . . . . . . . . . . Increase pressure at governor
4 - Ignition electrode incorrectly adjusted Adjust
5 - Electrode grounded due to broken . .
insulation Replace
6 - High voltage cable defective . . . . . . . Replace
7 - High voltage cable deformed by high
temperature Replace and protect
8 - Ignition transformer defective . . . . . . Replace
9 - Incorrect valve or transformer . . . . . .
electrical wiring Check
10 - Defective control box. . . . . . . . . . . . . Replace
11 - A closed valve upline the gas train . . Open
12 - Air in pipework. . . . . . . . . . . . . . . . . . Bleed air
13 - Gas valves unconnected or with . . . .
interrupted coil Check connections or replace coil
3 blinks The burner does not
switch on, and the
lockout appears
14 - Air pressure switch in operating posi-
tion Adjust or replace
The burner switches
on, but then stops in
lockout
- Air pressure switch inoperative due to
insufficient air pressure:
15 - Air pressure switch incorrectly
adjusted. Adjust or replace
16 - Pressure switch pressure test point .
pipe blocked Clean
17 - Poorly adjusted head. . . . . . . . . . . . . Adjust
18 - High pressure in the furnace . . . . . . . Connect air pressure switch to
fan suction line
Lockout during pre-
purging phase 19 - Defective motor control contactor . . . (only three-phase version) Replace
20 - Defective electrical motor . . . . . . . . . Replace
21 - Motor lockout (defective electrical
motor) Replace
4 pulses The burner switches
on, but then stops in
lockout
22 - Flame simulation . . . . . . . . . . . . . . . . Replace the control box
Lockout when
burner stops 23 - Permanent flame in the combustion . head or flame simulation Eliminate persistence of flame or replace control box
7 blinks Theburnergoesinto
lockout immediately
following the
appearance of the
flame
24 - The operation solenoid lets little gas.
through Increase
25 - Ionisation probe incorrectly adjusted. Adjust
26 - Insufficient ionisation (less than 5 A). Check probe position
27 - Earth probe . . . . . . . . . . . . . . . . . . . . Withdraw or replace cable
28 - Burner poorly grounded. . . . . . . . . . . Check grounding
29 - Phase and neutral connections
inverted Invert them
30 - Defective flame detection circuit . . . . Replace the control box
Burner goes into
lockout during oper-
ation
31 - Probe or ionisation cable grounded. . Replace worn parts

5858
13
10 blinks The burner does not
switch on, and the
lockout appears
32 - Incorrect electrical wiring. . . . . . . . . . Check
Theburnergoesinto
lockout 33 - Defective control box. . . . . . . . . . . . . Replace
34 - Presence of electromagnetic . . . . . .
disturbances in the thermostat lines
35 - Presence of electromagnetic. . . . . . .
disturbance
Filter or eliminate
Use the radio disturbance pro-
tection kit
No blink The burner does not
start 36 - No electrical power supply . . . . . . . . Close all switches - Check con- nections
37 - A limiter or safety control device is
open Adjust or replace
38 - Line fuse blocked . . . . . . . . . . . . . . . Replace
39 - Defective control box. . . . . . . . . . . . . Replace
40 - No gas supply . . . . . . . . . . . . . . . . . . Open the manual valves
between contactor and train
41 - Mains gas pressure insufficient. . . . . Contact your GAS COMPANY
42 - Minimum gas pressure switch fails to
close Adjust or replace
The burner contin-
ues to repeat the
start-up cycle, with-
out lockout
43 - The gas pressure in the gas mains
lies very close to the value to which
the minimum gas pressure switch has
been set. The sudden drop in pres-
sure after valve opening causes tem-
porary opening of the pressure switch
itself, the valve immediately closes
and the burner comes to a halt. Pres-
sure increases again, the pressure
switch closes again and the ignition
cycle is repeated. And so on
Reduce the minimum gas pres-
sure switch intervention pres-
sure. Replace the gas filter
cartridge.
Ignition with pulsa-
tions 44 - Poorly adjusted head. . . . . . . . . . . . . Adjust
45 - Ignition electrode incorrectly adjusted Adjust
46 - Incorrectly adjusted fan air damper:
too much air Adjust
47 - Output during ignition phase is too
high Reduce
Signal Problem Possible cause Recommended remedy

5858 14
NORMAL OPERATION / FLAME DETECTION TIME
The control box has a further function to guarantee the correct burner operation (signal: GREEN LED perma-
nently on).
To use this function, wait at least ten seconds from the burner ignition and then press the control box button for
a minimum of 3 seconds.
After releasing the button, the GREEN LED starts flashing as shown in the figure below.
The pulses of the LED constitute a signal spaced by approximately 3 seconds.
The number of pulses will measure the probe DETECTION TIME since the opening of gas valves, according to
the following table:
KIT INTERFACE ADAPTER RMG TO PC Code 3002719
BURNER START UP CYCLE DIAGNOSTICS
During start-up, indication is according to the following table:
SIGNAL FLAME DETECTION TIME This is updated in every burner start-up.
Once read, the burner repeats the start-up
cycle by briefly pressing the control box
button.
WARNING
If the result is > 2s, ignition will be retarded.
Check the adjustment of the hydraulic brake
of the gas valve, the air damper and the
combustion head adjustment.
1 blink 0.4s
2 blinks 0.8s
6 blinks 2.8s
COLOUR CODE TABLE
Sequences Colour code
Pre-purging 
Ignition phase 
Operation, flame ok 
Operating with weak flame signal 
Electrical supply lower than ~170V 
Lock-out 
Extraneous light 
Key: Off  Yellow Green Red
GREEN LED on
wait at least 10s Press button for > 3s signal signal
Interval
3s

5858
15
OPERATING FAULT DIAGNOSTICS
The control box has a self-diagnostic system, which easily allows identifying the operating faults (RED LED
signal).
ITo use this function, wait at least ten seconds from the safety lock out, and then press the reset button for a
minimum of 3 seconds.
After releasing the button, the RED LED starts flashing as shown in the diagram below.
The pulses of the LED constitute a signal spaced by approximately 3 seconds.
The number of pulses will provide the information on the possible faults, according to the table below:
SIGNAL PROBABLE CAUSE
2 flashes The flame does not stabilise at the end of the safety time:
– faulty ionisation probe;
– faulty or soiled gas valves;
– neutral/phase exchange;
– faulty ignition transformer;
– poor burner regulation (insufficient gas).
3 flashes Min. air pressure switch does not close:
– air pressure switch faulty;
– air pressure switch incorrectly regulated;
– max. air pressure switch triggered (if installed).
4 flashes Min. air pressure switch does not open or light in the chamber before firing:
– air pressure switch faulty;
– air pressure switch incorrectly regulated.
7 flashes Loss of flame during operations:
– poor burner regulation (insufficient gas);
– faulty or soiled gas valves;
– short circuit between ionisation probe and earth.
8 flashes – Not used.
10 flashes – Wiring error or internal fault.
RED LED on
wait at least 10 s Press button for > 3 s Signal Signal
Interval
3 s

5858 16
ACCESSORIES
• RADIO DISTURBANCE PROTECTION KIT code 3010386
If the burner is installed in places particularly subject to radio disturbance (emission of signals exceeding 10
V/m) owing to the presence of an INVERTER, or in applications where the length of the thermostat
connections exceeds 20 metres, a protection kit is available as an interface between the control box and the
burner.

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