Riello GAS 4 Quick start guide

2915860 (0)
Installation, use and maintenance instructions
Gas burner
CODE MODEL TYPE
3751682 GAS 4 516 T80

5860
1
TECHNICAL FEATURES
DIMENSIONS
Thermal output
180 - 470 kW 154.800 - 404.200 kcal/h
Fuel
Natural gas Pci 8 - 10 kWh/m
3
= 7000 - 8600 kcal/m
3
Minimum gas pressure
For maximum output 9.8 mbar are needed measured at the coupling
with nil pressure in the combustion chamber and gas with calorific val-
ue of 8600 kcal/m
3
Maximum gas pressure 150 mbar
Electrical supply Three phase 380 V + 10% - 10% ~ 60Hz with neutral
Motor 1.5 A / 380 V
Ignition transformer Primary: 1.8A / 220V - Secondary: 1 x 8 kV - 30 mA
Absorbed electrical power 0.6 kW
1– Air shutter control
2– Air shutter lock-nut
3– Control box re-set button
4– Fair leads
5– Wiring terminal block
6– Re-set push-button of the motor
overload relay
7– Air pressure switch
8– Gas pressure test-point Fig. 1
8
7
5
4
3
21
S7513
6
Boiler front-plate
drilling
*Length available with special blast tube to be separately required.
Burner
410 610187
*320
397
97
292
165
ø 150
Rp 1 1/2
S7497 S7498
160
160
165 M10
D1785

5860
2
EQUIPMENT
FIXING TO THE BOILER
GAS SUPPLY
Quantity Burner accessories
1 Flange
1 Gasket
8 Screws
1 Flange gasket
Separate the combustion head from the
burner body by loosening the screws 1)
and 2) and with drawing the group A)
from the holding bars 3).
Fix the group B) to the boiler front plate 4)
using the gasket 5) provided as acces-
sory.
23 5 4
1
AB
S7499
1- Gas pipe line 7- Gas shut off valve
2- Cock valve 8- Burner
3- Filter 9- Gas safety shut off valve
4- Pressure stabilizer 10 - Gas leak control device
5- Pressure test-point 11 - Isolator joint
6- Minimal gas pressure switch
5
8
79
5
6
43
10
21
S7514
11
5

5860
3
WORKING RANGE
COMBUSTION CHAMBER PRESSURE - MAXIMUM OUTPUT
(in compliance with DIN 4788)
MINIMUM GAS PRESSURE - OUTPUT
Pressure : detected at the pressure test-point 7) (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 350 kW it is necessary a gas pressure of 7 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
7) is: 7 + 2 = 9 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/m
3
.
CORRELATION BETWEEN GAS PRESSURE AND BURNER OUTPUT
kW
kcal/h
mbar
D1786
kW
kcal/h
mbar
D1787

5860
4
BURNER ELECTRICAL WIRING
(carried out in the factory)
D2656
CMV Fan motor contactor
F1 Protection against radio interference
MB Burner terminal strip
MV Fan motor
PA Air pressure switch
RMG Control box
RT Overload
SSuppressor
SO Ionisation probe
TA Ignition transformer
TB Burner earth
KEY TO LAYOUT
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.

5860
5
ELECTRICAL CONNECTIONS TO THE WIRING TERMINAL BLOCK
(to be carried out by the installer)
Notice
- Leads minimal section 1 mm
2
.
- The electric wiring carried out by the installer must be in compliance with the rules in force in the Coun-
try.
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 - Gas train : fair lead Pg 13.5,
sheath ø 13
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.
- Checkthe stopof theburner, byopening theboiler thermostatand theburner 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
H1 Remote lock-out signal of leak
detection control device
IN Burner manual stop switch
MB Burner terminal strip
PG Min. gas pressure switch
TL Limit control device system
TS Safety control device system
VPS Leak detection control device
VR Gas adjustment valve
VS Gas safety valve
XP7 Plug for leak detection control device
KEY TO LAYOUT
D2657
S7505
F Ampere T6
S mm21

5860 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 7) (fig.1)
The air pressure switch setting shall be carried out after having
set all other adjustment 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 mbarand repeatthe
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 elec-
trode, damage may occur to the control box amplifier.
Screw
Plug for pressure measure
Pressure switch
S7506
1 ÷ 10
mbar
Adjustment knob
S7507
0 - 1 mm
2 - 4 mm
Probe position Ignition electrode position
S7508

5860 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 270 kW, assuming an efficiency of 90% the burner output should
be 300 kW.
From the diagram it can be seen that the air and gas settings for this rating should be no. 3.
25681
3
4
7
S7518
kcal/h kW
Burner output
Set-point number = for air and gas
D1792

5860 8
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.
MOTOR LOCK-OUT
This is caused by the thermal 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
Normal Lock-out because no ignition
Thermostat
Motor
Ignition transf.
Start valve
Adjust. valve
Lock-out
2 s 40 s 10 s 2 s 40 s 3 s max.
D1798

5860 9
BURNER STARTING DIFFICULTIES AND THEIR CAUSES
OPERATING FAULTS
Lock-out may occur, because of: - flame failure;
- ionization probe earthed;
- air pressure switch open.
Shut-off may depend on the gas pressure switch opening.
DIFFICULTIES CAUSES
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 the flame, or
its wiring to the control box is broken, or there is a fault on its insu-
lation to earth.
The ionization current is weak (lower than 3 µA).
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 pipe-
work).
The valve is defective.
The pipe has not been purged from the air.
The ignition arc is irregular or has failed.
The burner does not pass
through the pre-purge peri-
od and the control box
goes to lock-out:
The air pressure switch does not change over: it has failed or the air
pressure is too low (combustion head bad set).
Flame simulation exists (or the flame really lights).
The burner does not start at
the thermostat closing, be-
cause of:
Gas is not supplied.
The gas pressure switch does not close: incorrectly adjusted.
The air pressure switch is changed over to the operational position.
The fuse of the control box is broken.
The burner repeats the
start-up cycle without oc-
curring the lock-out:
This particular trouble is caused by the gas pipework pressure that
is very close to the value of the gas pressure switch setting, owing
to the sudden pressure decrease the valve opens and actuates -
onlytemporaneously -the opening ofthe pressureswitch, thereafter
the valve closes, the motor stops and the pressure increases again;
the pressure switch closes and the start-up cycle is repeated and so
forth.
To prevent this trouble, setting the gas pressure switch at a lower
value.