Riello RL 250 MZ Quick start guide

20044425 (2) - 05/2013
Installation, use and maintenance instructions
安装、使用及维护手册
Light oil burners
轻油燃烧器
Two-stage operation
两段火运行
CODE - 编码 MODEL - 型号 TYPE - 类型
20044403 RL 250 MZ 970 T
GB
CN

1
CONTENTS
Technical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 2
List of available models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Burner description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Description of panel board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Packaging - Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Standard equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Max. dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Firing rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Test boiler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Boiler plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Blast tube length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Securing the burner to the boiler . . . . . . . . . . . . . . . . . . . . . . . . . 7
Accessibility to the interior of the combustion head . . . . . . . . . . . 7
Choice of nozzles for the 1st and 2nd stage . . . . . . . . . . . . . . . . 7
Nozzle assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Position of electrodes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Combustion head setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Fuel supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Hydraulic connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Pump priming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Burner calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Servomotor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Air pressure switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Final checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Burner operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Start-up cycle diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Resetting the control box and using diagnostics . . . . . . . . . . . . 15
Faults - Probable cause - Suggested remedy . . . . . . . . . . . . . . 16
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Appendix
Panel board layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
GB

2
TECHNICAL DATA
(1) Reference conditions: Ambient temperature 20°C - Barometric pressure 1000 mbar - Altitude 100 m a.s.l.
(2) Sound pressure measured in manufacturer’s combustion laboratory, with burner operating on test boiler and at maximum rated output.
ELECTRICAL DATA
Motor IE1
Motor IE2
MODEL RL 250 MZ
TYPE 970 T
OUTPUT (1)
DELIVERY (1)
2nd stage
(min - max) kW kg/h 1250 ÷ 2700 106 ÷ 228
1st stage
(min) kW kg/h 600 51
FUEL LIGHT OIL
- net calorific value kWh/kg
Mcal/kg 11.8 10.2 (10.200 kcal/kg)
- density kg/dm30.82 - 0.85
- viscosity at 20 °C mm2/s max 6 (1.5 °E - 6 cSt)
OPERATION - Intermittent (min. 1 stop in 24 hours)
- Two-stage (high and low flame) and single-stage (all - nothing)
NOZZLES number 2
STANDARD APPLICATIONS Boilers: water, steam, diathermic oil
AMBIENT TEMPERATUR °C 0 - 40
COMBUSTION AIR TEMPERATURE °C max 60
PUMP delivery at 12 bar (kg/h)
pressure range (bar)
fuel temperatur (°C)
230
10 - 21
90
CONFORMITY TO EC DIRECTIVES 2004/108 - 2006/95 - 2006/42
NOISE LEVELS (2) dBA 85.4
Model RL 250 MZ
Electrical supply V/Ph/Hz 400/3/50
Auxiliary power supply V/Ph/Hz 230/1/50
Electric motor rpm
W
V
A
2900
6600
230/400
24.3 - 14
Ignition transformer V1 - V2
I1 - I2 230 V - 2 x 5 kV 1.9 A - 35 mA
Electrical power consumption W max 7200
Electrical protection IP 54
Model RL 250 MZ
Electrical supply V/Ph/Hz 400/3/50
Auxiliary power supply V/Ph/Hz 230/1/50
Electric motor rpm
W
V
A
2900
7500
230/400
23.9 - 13.8
Ignition transformer V1 - V2
I1 - I2 230 V - 2 x 5 kV 1.9 A - 35 mA
Electrical power consumption W max 7200
Electrical protection IP 54

3
DESIGNATION OF BURNER SERIES RL
Series : R
Size
Fuel : S
L
LS
Natural gas
Light oil
Light oil / Methane
Setting :
Head : TC Standard head
TL Extended head
Flame control system :
FS1
FS2 Standard (1 stop every 24 h) Continuos working (1 stop every 72 h)
Electrical supply to the system :
3/400/50
3/230/50
Auxiliary voltage :
230/50/60
110/50/60
R L 250 TC
Emission : ... Class 1 EN267 - EN676
MZ Class 2 EN267 - EN676
BLU Class 3 EN267 - EN676
MX Class 2 EN267
Class 3 EN676
FS1 3/400/50 230/50/60
BASIC DESIGNATION
EXTENDED DESIGNATION
LIST OF AVAILABLE MODELS
Designation Electrical supply Starting Code
RL 250 MZ 400V-50Hz Direct 20044403
3N / 400V / 50Hz
3 / 230V / 50Hz
230V / 50-60Hz
110V / 50-60Hz
N Heavy oil
E Electronic cam
EV Electronic cam and variable speed (with Inverter)
P Air/gas proportioning valve
BTwo-stage

4
BURNER DESCRIPTION (A)
1Fan
2 Fan motor
3 Air gate valve servomotor
4 Combustion head
5 Ignition electrodes
6 Flame stability disk
7 Panel board - cover
8 Air inlet to fan
9 Manifold
10 Thermal insulation screen for securing
burner to boiler
11 Shutter
12 Air pressure test point
13 Pump
14 Photoelectric cell
15 Pump motor
16 Valve group
17 Screw for combustion head adjustment
DESCRIPTION OF PANEL BOARD (B)
1 Air pressure switch
2 Voltage free contacts relay
3 Control box
4 Two switches:
- one “burner off - on”
- one for “1st - 2nd stage operation”
5 Main supply terminal strip
6 Motor contactor and thermal cut-out with
reset button
7 Pump motor relay
8 Ignition transformer
9 Connector for Status
10 Entry for power cables and external leads
N.B.
Two types of burner failure may occur:
Control box lock-out: if the control box 3)(B)
pushbutton (red led) lights up, it indicates that
the burner is in lock-out.
To reset, hold the pushbutton down for between
1 and 3 seconds.
Motors trip: release by pressing the push but-
ton of the thermal cutout relay.
(A)
(B)
D3940
D3941
3
4
5
6
7
8
11
12
14
15
17
2
13
16
1
9
10
6
10
4
3
2
7
1
8
9
5

5
PACKAGING - WEIGHT (A) - Approximate
measurements
• The burner stands on a wooden base which
can be lifted by fork-lifts. Outer dimensions of
packaging are indicated in (A).
• The weight of the burner complete with pack-
aging is indicated in Table (A).
STANDARD EQUIPMENT
1 - Thermal insulation screen
4 - Screws to secure the burner flange to the
boiler: M 16 x 40
1 - Instruction booklet
1 - Spare parts list
MAX. DIMENSIONS (B) -Approximate
measurements
The maximum dimensions of the burner are
given in (B). Bear in mind that inspection of the
combustion head requires the burner to be
opened by pulling the rear part back on the piv-
ots.
The overall dimensions of the burner when open
are indicated by M.
(A)
BA
D
E
M
G
L
H
mm ABCkg
RL 250 MZ 1400 725 1040 140
mm A B D E G H L M
RL 250 MZ 705 378 222 436 910 596 432 1163
(B)
D36
D3943

6
FIRING RATES (A)
1st stage DELIVERY must be selected within
area A of the adjacent diagrams.
2nd stage DELIVERY must be selected within
area B. This area provides the maximum delivery
of the burner in relation to the pressure in the
combustion chamber.
Important: The FIRING RATE area values have
been obtained considering a surrounding tem-
perature of 20°C, and an atmospheric pressure
of 1000 mbar (approx. 100 m above sea level)
and with the combustion head adjusted as
shown on page 8.
BOILERS (B)
The burner/boiler matching does not pose any
problems if the boiler is CE type-approved and
its combustion chamber dimensions are similar
to those indicated in diagram (B).
If the burner must be combined with a boiler that
has not been CE type-approved and/or its com-
bustion chamber dimensions are clearly smaller
than those indicated in diagram (B), consult the
manufacturer.
TEST BOILER (B)
The firing rates were set in relation to special
test boilers, according to EN 267 regulations.
Figure (B) indicates the diameter and length of
the test combustion chamber.
Example:
RL 250 MZ burner
Output 1770 kW:
diameter 80 cm - length 3 m.
(A)
Comb. chamber - m
(B)
D1637
D3944
0,25 kg/h
RL 250 MZ
mbar
20
18
16
14
12
10
8
6
4
2
0
kW
3200
2800
2400
2000
1600
1200800
400
-2
200
0
A B

7
INSTALLATION
BOILER PLATE (A)
Drill the combustion chamber locking plate as
shown in (A). The position of the threaded holes
can be marked using the thermal screen sup-
plied with the burner.
BLAST TUBE LENGTH (B)
The length of the blast tube must be selected
according to the indications provided by the
manufacturer of the boiler, and in any case it
must be greater than the thickness of the boiler
door complete with its fettling.
For boilers with front flue passes 1) or flame
inversion chambers, protective fettling in refrac-
tory material 5) must be inserted between the
boiler fettling 2) and the blast tube 4).
This protective fettling must not compromise the
extraction of the blast tube.
For boilers having a water-cooled front the
refractory fettling 2)-5)(B) is not required unless
it is expressly requested by the boiler manufac-
turer.
SECURING THE BURNER TO THE
BOILER (B)
• Slip the thermal insulation screen (standard
equipment) onto the blast tube 4) (B).
• Place entire burner on the boiler hole
(arranged previously, see fig. (A), and fasten
with the screws given as standard equipment.
The coupling of the burner-boiler must be air-
tight.
ACCESSIBILITY TO THE INTERIOR OF
THE COMBUSTION HEAD (C)
• Remove the covering hood of the panel
board.
• Loosen the screws 1).
• Remove the extensions 3) after loosening the
cap 2).
• Remove the screws 4) and disconnect the
light oil adduction tubes 6).
Note: while unscrewing, some fuel may leak
out.
• Extract the combustion head 5).
CHOICE OF NOZZLES FOR 1ST AND 2ND
STAGE
Both nozzles must be chosen from among those
listed in Table (D).
The first nozzle determines the delivery of the
burner in the 1st stage.
The second nozzle works together with the 1st
nozzle to determine the delivery of the burner in
the 2nd stage.
The deliveries of the 1st and 2nd stages must
be contained within the value range indicated on
page 2.
Use nozzles with a 60° spray angle at the rec-
ommended pressure of 12 bar.
As a rule the two nozzles have equal deliveries
but the 1st stage nozzle may have a delivery
less than 50% of the total delivery when a
reduction of the counter-pressure peak is
desired at the moment of starting (the burner
allows good combustion rates also with a 33 -
100 % ratio between the 1st and 2nd stage).
Example
Boiler output = 1630 kW - efficiency 90 %
Output required by the burner =
1630 : 0,9=1812 kW;
1812 : 2 =906 KW per nozzle;
therefore, two equal, 60°, 12 bar nozzles are
required:
1° = 18 GPH - 2° = 18 GPH,
or the following two different nozzles:
1° = 15 GPH - 2° = 21 GPH.
NOTE: Instead of the nozzles given in tab. (D),
you can use the following nozzle types:
•DELAVAN B 60°;
•MONARCH PLP 70° (up to 30 GPH).
5
2
1
1
4
123
45
6
mm A B C
RL 250 MZ 230 325 - 368 M16
(A)
(B)
(C)
D455
D3945
D3946
Nozzle GPH kg/h kW
12 bar
10 bar 12 bar 14 bar
type
HAGO S-S 60°
12.0
13.0
14.0
15.0
16.0
17.0
18.0
19.0
20.0
22.0
24.0
25.0
26.0
28.0
30.0
32.0
34.0
35.0
44.16
47.84
51.52
55.20
58.88
62.57
66.25
69.93
73.61
80.97
88.33
92.00
95.69
103.05
110.41
117.77
125.13
128.81
48.73
52.79
56.86
60.92
64.98
69.04
73.10
77.16
81.22
89.34
97.47
101.53
105.59
113.71
121.83
129.95
138.08
142.14
52.96
57.38
61.79
66.20
70.62
75.03
79.44
83.86
88.27
97.10
105.93
110.34
114.75
123.58
132.41
141.24
150.06
154.48
582.36
630.89
679.42
727.95
776.48
825.01
873.54
922.07
970.60
1067.66
1164.72
1198.00
1261.78
1358.84
1455.90
1533.47
1629.31
1667.23
(D)

8
NOZZLE ASSEMBLY
Fit two nozzles with the box spanner 1)(A) (16
mm), after having removed the plastic plugs
2)(A), fitting the spanner through the central
hole in the flame stability disk.
Do not use any sealing products such as gas-
kets, sealing compound, or tape. Be careful to
avoid damaging the nozzle sealing seat. The
nozzles must be screwed into place tightly but
not to the maximum torque value provided by
the wrench.
The nozzle for the 1st stage of operation is the
one lying beneath the firing electrodes Fig. (B).
If it proves necessary to change a nozzle with the
burner already fitted to the boiler, proceed as
outlined below:
- Retract the burner on its slide bars as shown
in fig. (C) page 7.
- Remove the nuts 1)(D) and the disk 2)(D).
- Use spanner 3)(D) to change the nozzles.
POSITION OF ELECTRODES (B)
Make sure that the electrodes are positioned as
shown in figure (B).
COMBUSTION HEAD SETTING (E)
Turn screw 17)(A)p. 2 until the notch identified is
aligned with the front surface of the line.
16
:
4-4,5 mm
(D)
(B)
D1249
D3947
6
5
4
3
2
1
0
1000
0
1
2
3
4
5
6
1500 2000 2500 3000 3500 kW
7
500
0
8
9
10
Electrode
(E)
D3948
N° Notches
Max burner output
(A) D691

9
FUEL SUPPLY
Double-pipe circuit (A)
The burner is equipped with a self-priming pump
which is capable of feeding itself within the limits
listed in the table at the side.
The tank higher than the burner A
The distance "P" must not exceed 10 meters in
order to avoid subjecting the pump's seal to
excessive strain; the distance "V" must not
exceed 4 meters in order to permit pump self-
priming even when the tank is almost com-
pletely empty.
The tank lower than the burner B
Pump depression values higher than 0.45 bar
(35 cm Hg) must not be exceeded because at
higher levels gas is released from the fuel, the
pump starts making noise and its working life-
span decreases.
It is good practice to ensure that the return and
suction lines enter the burner from the same
height; in this way it will be more improbable that
the suction line fails to prime or stops priming.
The loop circuit
A loop circuit consists of a loop of piping depart-
ing from and returning to the tank with an auxil-
iary pump that circulates the fuel under
pressure. A branch connection from the loop
goes to feed the burner. This circuit is extremely
useful whenever the burner pump does not suc-
ceed in self-priming because the tank distance
and/or height difference are higher than the val-
ues listed in the Table.
Note: We advise you to fit, on the loop circuit, an
oil pressure switch connected to the thermo-
static series. It will provide clearance to the
burner only if there ispressure.
Key
H =Pump/Foot valve height difference
L =Piping length
Ø =Inside pipe diameter
1 =Burner
2=Pump
3=Filter
4 =Manual on/off valve
5 =Suction line
6 =Foot valve
7 =Rapid closing manual valve
remote controlled (Italy only)
8 =On/off solenoid valve (Italy only
9 =Return line
10 =Check valve (Italy only)
HYDRAULIC CONNECTIONS
The pumps are equipped with a by-pass that
connects return line and suction line. The
pumps are installed on the burner with the by-
pass closed by screw 6), see diagram page 14.
It is therefore necessary to connect both hoses
to the pump.
The pump will break immediately if it is run with
the return line closed and the by-pass screw
inserted.
Remove the plugs from the suction and return
connections of the pump.
Insert the hose connections with the supplied
seals into the connections and screw them
down.
Take care that the hoses are not stretched or
twisted during installation.
Install the hoses where they cannot be stepped
on or come into contact with hot surfaces of the
boiler and where they do not hamper the open-
ing of the burner.
Now connect the other end of the hoses to the
suction and return lines by using the supplied
nipples.
10 cm
VH+H- P
2
3
5
9
4
8
5
9
10
7
6
6
7
1
A
B
+ H
- H
(m)
L (m)
Ø (mm)
12 14 16
+ 4,0 71 138 150
+ 3,0 62 122 150
+ 2,0 53 106 150
+ 1,0 44 90 150
+ 0,5 40 82 150
0 36 74 137
- 0,5 32 66 123
- 1,0 28 58 109
-2,0 194281
-3,0 102653
- 4,0 - 10 25
D3949
(A)

10
PUMP
1 - Suction G 1/2"
2 - Return G 1/2"
3 - Pressure gauge attachment G 1/8"
4 - Vacuum meter attachment G 1/8"
5 - Pressure adjustment screw
6 - By-pass screw
A - Min. delivery rate at 12 bar pressure
B - Delivery pressure range
C - Max. suction depression
D - Viscosity range
E - Light oil max. temperature
F - Max. suction and return pressure
G - Pressure calibration in the factory
H - Filter mesh width
PUMP PRIMING
- Before starting the burner, make sure that
the tank return line is not clogged.
Obstructions in the line could cause the
sealing organ located on the pump shaft
to break. (The pump leaves the factory with
the by-pass closed).
- For self-priming to take place, the screw
3)(A) of the pump must be loosened in order
to bleed off the air contained in the suction
line.
- Start the burner by closing the thermostats/
pressure switches, and with the switch 1)(B)
in the "ON" position. The rotation of the
pump motor must be as indicated in Fig.C.
- The pump can be considered to be primed
when the light oil starts coming out of the
screw 3). Stop the burner: switch 1)(B) set to
"OFF" and tighten the screw 3).
The time required for this operation depends
upon the diameter and length of the suction tub-
ing. If the pump fails to prime at the first starting
of the burner and the burner locks out, wait
approx. 15 seconds, reset the burner, and then
repeat the starting operation as often as
required. After 5 or 6 starting operations allow 2
or 3 minutes for the transformer to cool.
Do not illuminate the UV cell or the burner will
lock out; the burner should lock out anyway
about 10 seconds after it starts.
Important: the a.m. operation is possible
because the pump is already full of fuel when it
leaves the factory. If the pump has been
drained, fill it with fuel through the opening on
the vacuum meter prior to starting; otherwise,
the pump will seize. Whenever the length of the
suction piping exceeds 20-30 meters, the supply
line must be filled using a separate pump.
BURNER CALIBRATION
FIRING
Set switch 1)(B) to "ON".
During the first firing, during the passage from
the 1st to the 2nd stage, there is a momentary
lowering of the fuel pressure caused by the fill-
ing of the 2nd stage nozzle tubing. This lowering
of the fuel pressure can cause the burner to
lock-out and can sometimes give rise to pulsa-
tions.
Once the following adjustments have been
made, the firing of the burner must generate a
noise similar to the noise generated during oper-
ation.
OPERATION
The optimum calibration of the burner requires
an analysis of the flue gases at the boiler outlet
and interventions on the following points.
• 1st and 2nd stage nozzles
See the information listed on page 7.
• Combustion head
The adjustment of the combustion head already
carried out (page 8) need not be altered unless
the 2nd stage delivery of the burner is changed.
• Pump pressure
12 bar: This is the pressure calibrated in the fac-
tory which is usually sufficient for most pur-
poses. Sometimes, this pressure must be
adjusted to:
10 bar in order to reduce fuel delivery. This
adjustment is possible only if the surrounding
temperature remains above 0 °C;
14 bar in order to increase fuel delivery or to
ensure firings even at temperatures of less than
0 °C.
In order to adjust pump pressure, use the screw
5)(A).
• 1st and 2nd stage fan air gate valve
See adjustments page 11 (Servomotor).
(B) D469
(A)
PUMP
SUNTEC TA 2
D1251
J7 C
A
B
C
D
E
F
G
H
kg/h
bar
bar
cSt
°C
bar
bar
mm
230
10 - 21
0,45
2,8 - 200
90
1,5
12
0,170
12
Burner
1°
2°
Stage
Off
On
(C) D3959
ROTATION OF PUMP MOTOR

11
SERVOMOTOR (A)
The servomotor, by means of connection mech-
anisms, simultaneously regulates air pressure
and delivery and the flow of fuel in use.
It features adjustable cams that operate as
many switches.
Cam 1:blue
Limits servomotor travel to 0° position. With the
burner off, the air damper is fully closed.
Cam 2:orange
Adjusts the position of the air damper to 1st
stage or pre-purging (factory set to 30° position).
Cam 3:red
Adjusts air damper travel or 2nd stage operation
without exceeding 90° (factory set to 90° posi-
tion).
Cam 4:black
Determines how early 2nd-stage valve is
switched on.
WARNING
Under no circumstances should
the BLUE cam be moved to the
right, beyond the air damper
closing position.
Under no circumstances should the RED
cam be moved to the left beyond 90°.
SERVOMOTOR
D3958
4
3
2
1

12
AIR PRESSURE SWITCH (A)
CO CHECK
Adjust the air pressure switch after having per-
formed all other burner adjustments with the air
pressure switch set to the start of the scale (A).
With the burner working at MIN output, insert a
combustion analyser in the stack and slowly
close the fan suction line inlet (for example, with
cardboard) until the Bacharach index is equal
to 2.
Slowly turn the appropriate knob clockwise until
the burner goes into lockout.
Check the indication of the arrow pointing
upwards on the graduated scale (A). Turn the
knob clockwise again, until the value show on
the graduated scale corresponds with the arrow
pointing downwards (A), and so recovering the
hysteresis of the pressure switch represented
by the white mark on a blue background,
between the two arrows.
Now check the correct start-up of the burner.
If the burner locks out again, turn the knob
slightly in an anticlockwise direction.
(A)
AIR PRESSURE SWITCH
D3951

13
FINAL CHECKS
• Obscure the photocell and switch on the ther-
mostats/pressure switches: the burner should
start and then lock-out about 5 s after opening
of the 1st stage operation valve.
• Illuminate the photocell and switch on the ther-
mostats/pressure switches: the burner should
start and then go into lock-out after about 10 s.
• Obscure the photocell while the burner is in
2nd stage operation, the following must occur
in sequence: flame extinguished within 1 s,
purging for about 20 s, sparking for about 5 s,
burner goes into lock out.
• Switch off control device TL followed by control
device TS while the burner is operating: the
burner should stop.
MAINTENANCE
Combustion
The optimum calibration of the burner requires
an analysis of the flue gases. Significant differ-
ences with respect to the previous measure-
ments indicate the points where more care
should be exercised during maintenance.
Pump
The delivery pressure must be stable at 12 bar.
The depression must be less than 0.45 bar.
Unusual noise must not be evident during pump
operation.
If the pressure is found to be unstable or if the
pump runs noisily, the flexible hose must be de-
tached from the line filter and the fuel must be
sucked from a tank located near the burner. This
measure permits the cause of the anomaly to be
traced to either the suction piping or the pump.
If the pump is found to be responsible, check to
make sure that the filter is not dirty. The vacuum
meter is installed upstream from the filter and
consequently will not indicate whether the filter is
clogged or not.
Contrarily, if the problem lies in the suction line,
check to make sure that the filter is clean and
that air is not entering the piping.
Filters
Check the following filter boxes:
• on line 3) • in the pump 2) • at the nozzle , and
clean or replace as required.
If rust or other impurities are observed inside the
pump, use a separate pump to lift any water and
other impurities that may have deposited on the
bottom of the tank.
Fan
Check to make sure that no dust has accumulat-
ed inside the fan or on its blades, as this condi-
tion will cause a reduction in the air flow rate and
provoke polluting combustion.
Combustion Head
Check to make sure that all the parts of the com-
bustion head are in good condition, positioned
correctly, free of all impurities, and that no defor-
mation has been caused by operation at high
temperatures.
Nozzles
Do not clean the nozzle openings. Replace the
nozzles every 2-3 years or whenever necessary.
Combustion must be checked after the nozzles
have been changed.
Photocell
Clean the glass cover from any dust that may
have accumulated. Photocell 1) is held in posi-
tion by a pressure fit and can therefore be re-
moved by pulling it outward forcefully.
Flexible hoses
Check to make sure that the flexible hoses are
still in good condition and that they are not
crushed or otherwise deformed.
Fuel tank
Approximately every 5 years, or whenever nec-
essary, suck any water or other impurities
present on the bottom of the tank using a sepa-
rate pump.
Boiler
Clean the boiler as indicated in its accompanying
instructions in order to maintain all the original
combustion characteristics intact, especially the
flue gas temperature and combustion chamber
pressure.
(A) D707
(B)
D1254
D709
(C)

14
BURNER OPERATION
BURNER STARTING (A) - (B)
Starting phases with progressive time intervals
shown in seconds:
• Thermostat/pressure switch TL closes.
After about 3s:
•0 s : The control box starting cycle begins.
•2 s : The fan motor starts. Servomotor (12)
starts, air damper opens in 1st stage position.
•3 s : The ignition transformer is connected.
The pump 3) sucks the fuel from the tank
through the piping 1) and the filter 2) and
pumps it under pressure to delivery. The pis-
ton 4) rises and the fuel returns to the tank
through the piping 5) - 7). The screw 6) closes
the by-pass heading towards suction and the
solenoid valves 8) - 9) - 10), de-energized,
close the passage to the nozzles.
22 s : Solenoid valves 8) and 9) open and the
fuel is sprayed out through the nozzle, igniting
when it comes into contact with the spark. This
is the 1st stage flame.
•29 s: The ignition transformer switches off.
•36 s: If the control device TR is closed or has
been replaced by a jumper wire, the 2nd stage
solenoid valve 10) opens and the servomotor
moves the air damper to 2nd stage position.
The starting cycle comes to an end.
STEADY STATE OPERATION
System equipped with one control device TR
Once the starting cycle has come to an end,set
0-auto-man selector to auto the command of the
2nd stage solenoid valve passes on to the con-
trol device TR that controls boiler temperature or
pressure.
• When the temperature or the pressure increas-
es until the control device TR opens, solenoid
valve 10) closes, and the burner passes from
the 2nd to the 1st stage of operation.
• When the temperature or pressure decreases
until the control device TR closes, solenoid
valve 10) opens, and the burner passes from
the 1st to the 2nd stage of operation, and so on.
• The burner stops when the demand for heat is
less than the amount of heat delivered by the
burner in the 1st stage. In this case, the control
device TL opens, and solenoid valves 8)-9)
close, the flame immediately goes out. The
fan's air gate valve closes completely.
Systems not equipped with control device
TR (jumper wire installed)
The burner is fired as described in the case
above. If the temperature or pressure increase
until control device TL opens, the burner shuts
down (Section A-A in the diagram).
FIRING FAILURE
Iftheburner does notfire,it goes into lock-outwith-
in 5 s of the opening of the 1st nozzle valve and 30
s after the closing of control device TL.
The control box red pilot light will light up.
UNDESIRED SHUTDOWN DURING OPERA-
TION
If the flame goes out during operation, the burner
shuts down automatically within 1 second and
automatically attempts to start again by repeat-
ing the starting cycle.
HYDRAULIC SYSTEM LAYOUT
1Pumpsuction
2Filter
3Pump
4 Pressure governor (with cut-off system)
5 Return pipe
6 By-pass screw
7Pumpreturn
8 Safety solenoid
9 1st stage valve
10 2nd stage valve
11 Filter
M Pressure gauge
V Vacuometer
(B)
(A)
5
6
23
4
M
V
8
910
11
1°
2°
71
Off Yellow Green Red
For further details see page 15.
*
LED
RMO *
D3950
LED
RMO *
D3394
D3395

15
BURNER START-UP CYCLE DIAGNOSTICS
During start-up, indication is according to the followig table:
RESETTING THE CONTROL BOX AND USING DIAGNOSTICS
The control box features a diagnostics function through which any causes of malfunctioning are easily identified (indicator: RED LED).
To use this function, you must wait at least 10 seconds once it has entered the safety condition (lock-out), and then press the reset button.
The control box generates a sequence of pulses (1 second apart), which is repeated at constant 3-second intervals.
Once you have seen how many times the light pulses and identified the possible cause, the system must be reset by holding the button down
for between 1 and 3 seconds.
The methods that can be used to reset the control box and use diagnostics are given below.
RESETTING THE CONTROL BOX
To reset the control box, proceed as follows:
-Hold the button down for between 1 and 3 seconds.
The burner restarts after a 2-second pause once the button is released.
If the burner does not restart, you must make sure the limit thermostat is closed.
VISUAL DIAGNOSTICS
Indicates the type of burner malfunction causing lock-out.
To view diagnostics, proceed as follows:
-Hold the button down for more than 3 seconds once the red LED (burner lock-out) remains steadily lit.
A yellow light pulses to tell you the operation is done.
Release the button once the light pulses. The number of times it pulses tells you the cause of the malfunction, according to the coding sys-
tem indicated in the table on page 16.
SOFTWARE DIAGNOSTICS
Reports burner life by means of an optical link with the PC, indicating hours of operation, number and type of lock-outs, serial number of control
box etc ...
To view diagnostics, proceed as follows:
-Hold the button down for more than 3 seconds once the red LED (burner lock-out) remains steadily lit.
A yellow light pulses to tell you the operation is done.
Release the button for 1 second and then press again for over 3 seconds until the yellow light pulses again.
Once the button is released, the red LED will flash intermittently with a higher frequency: only now can the optical link be activated.
Once the operations are done, the control box’s initial state must be restored using the resetting procedure described above.
The sequence of pulses issued by the control box identifies the possible types of malfunction, which are listed in the table on page 16.
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
BUTTON PRESSED FOR CONTROL BOX STATUS
Between 1 and 3 seconds Control box reset without viewing visual diagnostics.
More than 3 seconds Visual diagnostics of lock-out condition:
(LED pulses at 1-second intervals).
More than 3 seconds starting from the visual
diagnostics condition Software diagnostics by means of optical interface and PC (hours of operation, malfunc- tions etc. can be viewed)
In the event of a burner lockout, more than two consecutive burner reset operations could cause damage to the installation. On the third
lockout, contact the Aftersales Service. If further lockouts or burner faults occur, interventions must only be made by qualified, authorised
personnel (as indicated in this manual, and in compliance with the laws and regulations currently in force).
Press reset
for > 3s 3sPulses Pulses
RED LED on
wait at least 10s Interval Lock-out
WARNING

16
SIGNAL FAULT PROBABLE CAUSE SUGGESTED REMEDY
No blink The burner does not
start 1 - No electrical power supply . . . . . . . . . . . . . . . . . . . . . . . . . Close all switches - Check fuses
2 - The thermostat/pressure switch TL is open . . . . . . . . . . . . Adjust or replace
3 - The thermostat/pressure switch TS is open . . . . . . . . . . . . Adjust or replace
4 - Control box lock-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Reset control box(no soonerthan10 safterthelock-out)
5 - Pump is jammed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replace
6 - Erroneous electrical connections . . . . . . . . . . . . . . . . . . . . Check connections
7 - Defective control box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replace
8 - Defective electrical motor . . . . . . . . . . . . . . . . . . . . . . . . . . Replace
2 led After pre-purge and the
safety time,
the burner goes to lock-
out
9 - No fuel in tank; water on tank bottom . . . . . . . . . . . . . . . . . Top up fuel level or suck up water
10 - Inappropriate head and air damper adjustments . . . . . . . . Adjust
11 - Light oil solenoid valves fail to open (1st stage or safety). . Check connections; replace coil
12 - 1st stage nozzle clogged, dirty, or deformed . . . . . . . . . . . Replace
13 - Dirty or poorly adjusted firing electrodes. . . . . . . . . . . . . . . Adjust or clean
14 - Grounded electrode due to broken insulation. . . . . . . . . . . Replace
15 - High voltage cable defective or grounded. . . . . . . . . . . . . . Replace
16 - High voltage cable deformed by high temperature. . . . . . . Replace and protect
17 - Ignition transformer defective . . . . . . . . . . . . . . . . . . . . . . . Replace
18 - Erroneous valves or transformer electrical connections. . . Check
19 - Control box defective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replace
20 - Pump unprimed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Prime pump and see “Pump unprimes”
21 - Pump/motor coupling broken . . . . . . . . . . . . . . . . . . . . . . . Replace
22 - Pump suction line connected to return line. . . . . . . . . . . . . Correct connection
23 - Valves up-line from pump closed . . . . . . . . . . . . . . . . . . . . Open
24 - Filters dirty: line - pump - nozzle. . . . . . . . . . . . . . . . . . . . . Clean
25 - Defective photocell or control box. . . . . . . . . . . . . . . . . . . . Replace photocell or control box
26 - Dirty photocell. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clean
27 - 1st stage operation of cylinder is faulty. . . . . . . . . . . . . . . . Change the cylinder
28 - Motor protection tripped . . . . . . . . . . . . . . . . . . . . . . . . . . . Reset thermal cut-out
29 - Defective motor command control device. . . . . . . . . . . . . . Replace
30 - Missing phase thermal cut-out trips........................Resetthermalcut-outwhenthirdphaseisre-connected
31 - Incorrect motor rotation direction . . . . . . . . . . . . . . . . . . . . Change motor electrical connections
4 led The burner starts
and then goes into lock-
out
32 - Photocell short-circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replace photocel
33 - Light is entering or flame is simulated. . . . . . . . . . . . . . . . . Eliminate light or replace control box
7 led Flame detachment 34 - Poorly adjusted head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Adjust
35 - Poorly adjusted or dirty firing electrodes. . . . . . . . . . . . . . . Adjust
36 - Poorly adjusted fan air gate: too much air (1st stage) . . . . Adjust
37 - 1st nozzle is too big (pulsation). . . . . . . . . . . . . . . . . . . . . . Reduce 1st nozzle delivery
38 - 1st nozzle is too small (flame detachment). . . . . . . . . . . . . Increase 1st nozzle delivery
39 - 1st nozzle dirty, or deformed. . . . . . . . . . . . . . . . . . . . . . . . Replace
40 - Inappropriate pump pressure . . . . . . . . . . . . . . . . . . . . . . . Adjust to between 10 and 14 bar
41 - 1st stage nozzle unsuited to burner or boiler . . . . . . . . . . . See Nozzle Table, page 10; reduce 1st stage
42 - Defective 1st stage nozzle . . . . . . . . . . . . . . . . . . . . . . . . . Replace
The burner does not
pass to 2nd stage 43 - Thermostat/pressure switch TR does not close . . . . . . . . . Adjust or replace
44 - Defective control box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replace
45 - 2nd stage sol. valve coil defective . . . . . . . . . . . . . . . . . . . Replace
46 - Piston jammed in valve unit . . . . . . . . . . . . . . . . . . . . . . . . Replace entire unit
Fuel passes to 2nd
stage
but air remains in 1st
47 - Low pump pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Increase
48 - 2nd stage operation of cylinder is faulty . . . . . . . . . . . . . . . Change cylinder
Burner stops at transi-
tion
between 1st and 2nd
stage.
Burner repeats starting
cycle
49 - Nozzle dirty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replace
50 - Photocell dirty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clean
51 - Excess air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reduce
Uneven fuel supply 52 - Check if cause is in pump. . . . . . . . . . . . . . . . . . . . . . . . . . Feed burner from tank
or fuel supply system located near burner
Internally rusted pump 53 - Water in tank. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Suck water from tank bottom with separate pump
Noisy pump, unstable
pressure 54 - Air has entered the suction line . . . . . . . . . . . . . . . . . . . . . Tighten connectors
- Depression value too high (higher than 35 cm Hg):
55 - Tank/burner height difference too great . . . . . . . . . . . . . . . Feed burner with loop circuit
56 - Piping diameter too small . . . . . . . . . . . . . . . . . . . . . . . . . . Increase
57 - Suction filters clogged. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clean
58 - Suction valves closed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Open
59 - Paraffin solidified due to low temperature. . . . . . . . . . . . . . Add additive to light oil
Pump unprimes after
prolonged pause 60 - Return pipe not immersed in fuel . . . . . . . . . . . . . . . . . . . . Bring to same height as suction pipe
61 - Air enters suction piping . . . . . . . . . . . . . . . . . . . . . . . . . . . Tighten connectors
Pump leaks light oil 62 - Leakage from sealing organ . . . . . . . . . . . . . . . . . . . . . . . . Replace pump
Smoke in flame
- dark Bacharach
- yellow Bacharach
63 - Not enough air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Adjust head and fan gate
64 - Nozzle worn or dirty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replace
65 - Nozzle filter clogged . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clean or replace
66 - Erroneous pump pressure . . . . . . . . . . . . . . . . . . . . . . . . . Adjust to between 10 - 14 bar
67 - Flame stability spiral dirty, loose, or deformed . . . . . . . . . . Clean, tighten in place, or replace
68 - Boiler room air vents insufficient. . . . . . . . . . . . . . . . . . . . . Increase
69 - Too much air. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Adjust head and fan gate
Dirty combustion head 70 - Nozzle or filter dirty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replace
71 - Unsuitable nozzle delivery or angle . . . . . . . . . . . . . . . . . . See recommended nozzles
72 - Loose nozzle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tighten
73 - Impurities on flame stability spiral. . . . . . . . . . . . . . . . . . . . Clean
74 - Erroneous head adjustment or not enough air . . . . . . . . . . Adjust; open gate valve
75 - Blast tube length unsuited to boiler. . . . . . . . . . . . . . . . . . . Contact boiler manufacturer
10 led The burner goes to lock-
out 76 - Connection or internal fault
77 - Presence of electromagnetic disturbance. . . . . . . . . . . . . . Use the radio disturbance protection kit

17
ACCESSORIES (optional)
•STATUS (see page 17) Code 3010322
•DIAGNOSTICS INTERFACE KIT Code 3002719
•SILENCER BOX KIT Code 3000779
•LONG HEAD KIT Code 3010422
•RADIO DISTURBANCE PROTECTION KIT
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.
Code 3010386

18
Appendix
1243
4B3 44 4
A
FEDC
D3942
Electrical connections
Use flexible cables according to EN 60 335-1 Regulations.
All the wires to connect to the burner must enter through
the supplied fairleads.
The fairleads and hole press-outs can be used in various
ways; the following lists show one possible solution:
1 - Three-phase power supply
2 - Single-phase power supply
3 - Triggering / Safety devices
4 - Available
Cable grommets used in the factory:
A - Fan motor
B - Servomotor
C - Pump motor
D - Safety solenoid
E- 1
st stage solenoid valve
F-2
nd stage solenoid valve
NOTES
The RL 250 MZ burner has been type- approved for intermittent operation. This means it shoulds compulsorily be stopped at least once every
24 hours to enable the control box to perform checks of its own efficiency at start-up. Burner halts are normally provided for automatically by the
boiler load control system.
If this is not the case, a time switch should be fitted in series to IN to provide for burner shut-down at least once every 24 hours.
Wiring must be performed by qualified personnel in accordance with the regulations in force in the country of destination.
Riello S.p.a. declines all responsibility for changes or wiring performed in any way other than that illustrated in these diagrams.
WARNING
Do not invert the neutral with the phase wire in the electricity supply line.
Layout of electric panel board
1
2
4
5
CONTENTS
References layout
RMO 88... operational layout
Electrical connections set by installer
3RMO 88... operational layout
2References layout
N. Page
/1.A1
Coordinates