Riello 521T80 Quick start guide

2915865 (4) - 05/2012
Installation, use and maintenance instructions
Forced draught gas burner
Code Model Type
3752182 GAS 3/2 521T80

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 3/2
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 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, 22.02.2010 Mr. G. Conticini
Burners Division Department
RIELLO S.p.A.

5865 1
TECHNICAL DATA
BURNER DESCRIPTION
OVERALL DIMENSIONS
Thermal output 2nd stage 130 - 340 kW - 112.000 - 292.000 kcal/h
Operation Two stages, high and low flame
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 value of
8600 kcal/m3
Maximum gas pressure 150 mbar
Electrical supply Single phase 220 V + 10% - 10% ~ 60Hz
Motor 1.85A / 220V
Capacitor 6.3 µF
Ignition transformer Primary: 1.8A / 220V - Secondary: 1 x 8 kV - 30 mA
Absorbed electrical power 0.4 kW
1– Air damper controlling motor
2– Control box re-set button
3– Fair leads
4– Wiring terminal block
5– Air pressure switch
6– Gas pressure test-point
Fig. 1
6
3
4
5
2
1
S7512
Boiler front-plate
drilling
*Length available with special blast tube to be separately required.
Burner
160
160
155 M10
410 610185
*320
397
97
292
165
ø 140
Rp 1 1/2
S7515 S7520
D1785

5865 2
STANDARDS EQUIPMENT
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.
FIXING TO THE BOILER
GAS SUPPLY
Quantity Description
1Flange
1Gasket
8 Screws
1 Flange gasket
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) provided as accessory.
23 5 4
1
AB
S7499
1- Gas pipe line 7- 1st stage gas shut off valve
2- Cock valve 8- 2nd stage gas shut off valve
3- Filter 9- Burner
4- Pressure stabilizer 10 - Gas safety shut off valve
5- Pressure test-point 11 - Isolator joint
6- Minimal gas pressure switch
5
9
710 5
8
431121
S7514
5
6

5865 3
WORKING RANGE
COMBUSTION CHAMBER PRESSURE 2nd STAGE OUTPUT
(in compliance with DIN 4788)
Min. output at 1st stage: 80 kW - 69.000 kcal/h.
MINIMUM GAS PRESSURE - OUTPUT
Pressure: detected at the pressure test-point 6) (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 7.
If the combustion chamber is pressurized at 2 mbar, the pressure detected at the test-point
6) is: 8 + 2 = 10 mbar.
If this value is too high, for very low gas pipework pressures, the gas gear 6) (page 7) 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
kW
kcal/h
mbar
D1788
kW
kcal/h
mbar
D1789

5865 4
BURNER ELECTRICAL WIRING
(carried out in the factory)
20052582
CCapacitor
F1 Protection against radio interference
K1 Relay
MB Burner terminal strip
MV Fan motor
PA Air pressure switch
RMG Control box
SO Ionisation probe
SM Servomotor
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.

5865 5
ELECTRICAL CONNECTIONS TO THE WIRING TERMINAL BLOCK
(to be carried out by the installer)
NOTICE
- Theelectricwiringcarriedoutbytheinstaller must bein compliancewiththerulesin forceintheCountry.
- Leads minimal section 1 mm2.
- 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.
FLAME MODULATION
The flame modulation is obtainable through the thermostat, controlling the second valve, connected
to the terminals 8 and 9.
FIXING OF THE ELECTRICAL WIRES
All the electrical wires, which are to be connected to the terminal block 4) (fig. 1) shall pass through
the fair leads 3) (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- Gas train : fair lead Pg 13.5,
sheath ø 13
5-2nd stage thermostat : fair lead Pg 13.5
6 / 7 - 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.
HRemote lock-out signal
MB Burner terminal strip
PG Minimum gas pressure swicth
TB Burner earth
TL Limit control device system
TR High-low mode load control system
TS Safety control device system
VS Gas safety shut off valve
V1 1° stage gas shut off valve
V2 2° stage gas shut off valve
D2660
S7523

5865 6
BURNER START-UP CYCLE
Air-purge: loosen the screw placed on the minimal gas pressure switch mounted on the gas train.
AIR PRESSURE SWITCH 5) (fig.1)
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 anticlockwise 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
3 - 4 mm
2 - 4 mm
Probe position Ignition electrode position
S7524

5865 7
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 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 225 kW, assuming an efficiency of 90% the burner output
should be 250 kW.
From the diagram it can be seen that the air and gas settings for this rating should be no. 4.
2
5
6
8
134 7
S7510
kcal/h kW
Burner output
Set-point number = for air and gas
D1793

5865 8
ADJUSTMENT OF THE AIR DAMPER MOTOR
STOP - Blue lever
This lever leaves the factory vertically positioned and corresponds to the complete closing of the air
damper.
A partial opening of the air damper might be obtained by moving leftwards this lever (+ on the label).
The new position of the air damper is detectable when the burner is off.
Do not overcome the position of the orange lever for the 1st stage.
1st STAGE - Orange lever
The orange lever controls the air damper position for the first flame, it is adjustable both for opening and
closing.
2nd STAGE - Red and black levers
The red lever controls the air damper position for the second flame, it is adjustable both for closing and
opening.
The black lever controls the opening of the second oil valve and it must always anticipate - for a bit -
the red lever, but never the orange one.
OPERATIONAL DIAGRAM
S7525
Black lever
Red lever
Orange lever
Blue lever
Opening + –Closing
The black lever must
anticipate the red one
S7526
Output gas
Time
Pre-purge
1st stage valve energizing
2nd stage valve energizing
38 s
10 s

5865 9
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 com-
bustion 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 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
S7511
Normal Lock-out because no ignition
Thermostat
Motor
Ignition transf.
1st valve
1st flame
2nd valve
2 s 40 s 10 s 2 s 40 s 3 s max.
D1799
2nd flame
Lock-out

5865 10
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

5865 11
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

5865 12
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

5865 13
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

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