Sime MURELLE User guide

Murelle
installation and servicing instructions
GB

CONTENTS
1 TECHNICAL FEATURES AND DIMENSIONS
1.1 DESCRIPTION OF BOILER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 DIMENSIONS
1.3 TECHNICAL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 FUNCTIONAL DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.5 INTERNAL VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.6 SYSTEM AVAILABLE HEAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 GENERAL REQUIREMENTS FOR INSTALLATION
2.1 BOILER ROOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 VENTILATION OF BOILER ROOM FOR “MURELLE” BOILERS
2.3 CONNECTING UP SYSTEM
2.4 WALL-MOUNTING PLATE
2.5 CONNECTING UP “MURELLE” FLUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.6 “MURELLE BF” COAXIAL AIR INLET-FLUE OUTLET ASSEMBLY . . . . . . . . . . . . . . . . . . . 8
2.7 “MURELLE BF” SEPARATE AIR INLET-FLUE OUTLET PIPES . . . . . . . . . . . . . . . . . . . . . . 10
2.8 CHARACTERISTICS OF FEEDWATER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.9 WATER FAILURE SAFETY DEVICE
2.10 SYSTEM FILLING
2.11 “MURELLE 20 TX CE IONO” BOILER SUPPLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.12 ELECTRICAL CONNECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.13 ELECTRONIC BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.14 TEMPERATURE SENSORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.15 ELECTRONIC IGNITION
2.16 INTERRUPTION OF THE THERMOCOUPLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.17 SMOKE SAFETY DEVICE
2.18 SMOKE PRESSURE SWITCH
2.19 DISASSEMBLY OF OUTER CASING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3 USE AND MAINTENANCE
3.1 PRELIMINARY CHECKS ON IGNITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2 DISASSEMBLY OF EXPANSION VESSEL
3.3 GAS VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.4 GAS VALVE ADJUSTMENT
3.5 ADJUSTMENT OF HEAT OUTPUT FOR HEATING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.6 PILOT BURNER ADJUSTMENT
3.7 CONVERSION TO DIFFERENT GAS
3.8 FILTER ON GAS PIPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.9 CLEANING AND MAINTENANCE
3.10 FAULT FINDING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

1
1 Technical features and dimensions
1.2 DIMENSIONS
Fig. 1
1.2.1 “MURELLE” version
1.2.1 “MURELLE BF” version
CONNECTIONS
R C.H. return 3/4”
M C.H. flow 3/4”
G Gas connection 3/4”
E Domestic water inlet 1/2”
U Domestic water outlet 1/2”
20 25
A ø mm 130 150
L mm 450 500
CONNECTIONS
R C.H. return 3/4”
M C.H. flow 3/4”
G Gas connection 3/4”
E Domestic water inlet 1/2”
U Domestic water outlet 1/2”
1.1 DESCRIPTION OF BOILER
“MURELLE - MURELLE BF” boilers are gas-fired ther-
mal appliances for central heating and D.H.W. produc-
tion. They are equipped with all safety and control devi-
ces required by the law and their technical and operating
features meet the requirements of the specifications on
the safety and use of combustible gas. In addition, they
are designed and built in accordance with the European
Directives EN 297 - EN 483.
These appliances can be fired by natural gas (methane)
and butane gas (G30) or propane gas (G31). This book-
let provides instructions for the following boiler models:
–“MURELLE 20 R CE IONO” with electronic ignition
and modulation (central heating only);
–“MURELLE 20 CE” with electronic modulation;
–“MURELLE 20 TX CE IONO” with electronic ignition
and modulation, forced draught;
–“MURELLE 20 CE IONO - 25 CE IONO” with electronic
ignition and modulation;
–“MURELLE 20 BFR CE IONO” with electronic ignition
and modulation (central heating only), forced-draught
sealed-room;
–“MURELLE 20 BF CE” with electronic modulation, for-
ced-draught sealed-room;
–“MURELLE 20 BF CE IONO - 25 BF CE IONO” with
electronic ignition and modulation, forced-draught
sealed-room.
The instructions given in this manual are provided for the
installer to ensure proper installation and perfect opera-
tion of the appliance.
20 BF 25 BF
L mm 130 150
B mm 450 500
Fig. 1/a

Power Smokes Smokes D.H.W. D.H.W. flow rate Minimum D.H.W. pressure
BOILER MODEL consumption temperature flow Heat Output ∆t 30°C D.H.W. flow rate Min. Max.
°C gr/s kW
I/min I/min bar bar
MURELLE 20 105 (150 vers. TX) 100 24.7 23.3 11.0 2 0.5 7
MURELLE 25 120 100 29 . 4 27.6 12.9 2 0.5 7
MURELLE 20 BF 150 136 17.2 23.3 11.0 2 0.5 7
MURELLE 25 BF 160 136 22 . 8 29.6 12.9 2 0.5 7
TABLE 2
Main burner nozzles Pilot injector Gas consumption (*)
BOILER MODEL Quantity Natural gas G30-G31 Natural gas G30-G31 Natural gas L.P.G. G30 L.P.G. G31
N° ø mm ø mm ø mm ø mm m3/h kg/h kg/h
MURELLE 20 13 1 . 30 0 . 75 0 . 25 0 . 20 2 . 72 2 . 02 1 . 99
MURELLE 25 15 1 . 30 0 . 77 - - 3 . 23 2 . 41 2 . 37
MURELLE 20 BF 13 1 . 30 0 . 75 0 . 27 0 . 20 2 . 72 2 . 02 1 . 99
MURELLE 25 BF 15 1 . 30 0 . 77 - - 3 . 47 2 . 58 2 . 54
1.3 TECHNICAL FEATURES
Heat Output Heat Input Electr. protection Maximum Expans. vessel Expans. vessel Weight
BOILER MODEL (adjustable) (adjustable) grade water head contents preloading
kW kW W bar l bar Kg
MURELLE 20 9.3 ÷ 23.3 10 . 8÷25 . 7– 37 140
MURELLE 25 11 . 6÷27 . 613 . 5÷30 . 6 –37 148
MURELLE 20 BF 9.3 ÷ 23.3 10 . 8÷25 . 7 IP 44 37 148
MURELLE 25 BF 15 . 1÷29 . 618 . 0÷32 . 8 IP 44 3 7 1 54
TABLE 1
TABLE 3
Burner gas pressure Gas supply pressure
BOILER MODEL Natural gas L.P.G. (G30) L.P.G. (G31) Natural gas L.P.G. (G30) L.P.G. (G31)
mbar mbar mbar mbar mbar mbar
MURELLE 20-20 BF 10 28 35 20 30 37
MURELLE 25-25 BF 11 28 35 20 30 37
TABLE 4
NOTE: The burner header gas pressure and inputs shown in the table refer to the boiler max. capacity. These values must be kept to
in the D.H.W. production.
2
(*) The gas consumptions refer to the calorific value at standard conditions at 15°C - 1013 mbar

1.4 FUNCTIONAL DIAGRAM
1.4.1 “MURELLE” model
3
KEY
1 Smoke chamber
2 85°C limit stat
3 Water-gas exchanger
4 Combustion chamber
5 Pressure switch valve
6 Water pressure switch
7 Expansion vessel
8 D.H.W. exchanger
9 D.H.W. sensor
10 Gas valve
11 Hydrometer
12 Safety valve
13 Filling unit
14 Boiler discharge
15 Circulation pump
16 Heating flow sensor
17 100°C safety stat
18 Air relief valve
19 Air separator
20 Antifreeze stat (optional)
21 Gas cock (optional)
22 Domestic water cock (optional)
23 Fixing jig (optional)
1.4.2 “MURELLE BF” model
KEY
1 Fan
2 85°C limit stat
3 Water-gas exchanger
4 Combustion chamber
5 Pressure switch valve
6 Water pressure switch
7 Expansion vessel
8 D.H.W. exchanger
9 D.H.W. sensor
10 Gas valve
11 Hydrometer
12 Safety valve
13 Filling unit
14 Boiler discharge
15 Circulation pump
16 Heating flow sensor
17 100°C safety stat
18 100°C safety stat (“IONO” versions)
19 Air relief valve
20 Air separator
21 Antifreeze stat (optional)
22 Gas cock (optional)
23 Domestic water cock (optional)
24 Fixing jig (optional)
Fig. 2
Fig. 2/a

4
1.5 INTERNAL VIEW
1.5.1 “MURELLE” model
KEY
1 Water pressure switch
2 D.H.W. sensor
3 D.H.W exchanger
4 Burner pressure inlet
5 Combustion chamber
6 85°C limit stat
7 Smoke capillary thermostat
8 Air relief valve
9 Water-gas exchanger
10 Heating flow sensor
11 100°C safety stat
12 Pilot burner
13 Gas valve
14 Circulation pump
15 Pressure switch valve
1.5.2 “MURELLE BF” model
KEY
1 Water pressure switch
2 D.H.W. sensor
3 D.H.W. exchanger
4 Blocking hinge
5 Pilot burner
6 Water-gas exchanger
7 85°C limit stat
8 Fan
9 Smoke pressure switch
10 Pressure intake (positive)
11 Pressure intake (negative)
12 100°C safety stat
13 Sealed chamber
14 Combustion chamber
15 Heating flow sensor
16 100°C safety stat (“IONO” versions)
17 Burner manifold
18 Gas valve
19 Circulation pump
20 Pressure switch valve
Fig. 3
Fig. 3/a

5
500 1000 1500
0
100
200
300
400
500
Portata l/h
600
20 25
1.6 SYSTEM AVAILABLE HEAD
RESIDUAL HEAD (mbar)
FLOW RATE l/h
Fig. 4

6
The boiler should be installed in a fixed location and
shall be carried out only by specialized and qualified
firms in compliance with all instructions contained in this
manual.
2.1 BOILER ROOM
The “MURELLE” version boilers may be installed in ade-
quately ventilated domestic rooms.
The “MURELLE BF” version boilers may instead be
installed, without any constraints regarding location or
supply of air for combustion, in any domestic rooms.
2.2 VENTILATION OF BOILER ROOM
FOR “MURELLE” BOILERS
It is essential that in rooms where open-flue gas applian-
ces are installed at least as much air can arrive as requi-
red by normal combustion of the gas consumed by the
various appliances. Consequently, it is necessary to
make openings in the walls for entry of air into the rooms.
These openings must meet the following requirements:
– have a total free section of at least 6 cm2for every kW
of heat input, with a minimum of 100 cm2(such ope-
nings may possibly be obtained by widening the gap
between the door and the floor);
– be situated towards the bottom of an external wall,
preferably opposite the one in which the burnt gases
outlet is located.
2.3 CONNECTING UP SYSTEM
Before proceeding to connect up the boiler, you are
recommended to get air to circulate in the piping in order
to eliminate any foreign bodies that might be detrimental
to the operating efficiency of the appliance. When
making the hydraulic connections, make sure that the
dimensions indicated in Figs. 1 - 1/a are respected.
If the connections supplied with the fixing jig are not used
for connecting up the pipes to the boiler, steel flexible
pipes must be used so as to avoid any stress being exer-
ted on the appliance.
In any case a shutoff valve must be mounted on the
washing-water intake piping.
The discharge pipe of the safety valve
(12 figs. 2 - 2/a)
must be connected to a collector funnel for channel-
ling away any discharge in the case of the safety
valve going into action.
The gas connection must be made using seamless steel
pipe (Mannesmann type), galvanized and with threaded
joints provided with gaskets, excluding three-piece con-
nections, except for initial and end connections.
Where the piping has to pass through walls, a suitable
insulating sleeve must be provided. When sizing gas
piping, from the meter to the boiler, take into account
both the volume flow rates (consumption) in m3/h and the
relative density of the gas in question. The sections of the
piping making up the system must be such as to gua-
rantee a supply of gas sufficient to cover the maximum
demand, limiting pressure loss between the gas meter
and any apparatus being used to not greater than:
– 1.0 mbar for family II gases (Natural gas)
– 2.0 mbar for family III gases (L.P.G.).
An adhesive data plate is stuck on the inside of the front
panel; it contains all the technical data identifying the boi-
ler and the type of gas for which the boiler is arranged.
2.4 WALL-MOUNTING PLATE
The wall-mounting plate is supplied along with the boiler
in cardboard packaging, and consists of two plates, with
a connecting strip and the corresponding fixing screws
(Fig. 5).
For assembly, proceed as follows:
– fasten the connecting strip to the top plate A and the
bottom plate B;
– once the template has been put together, fasten the
plate A on the wall with the two hexagonal-head
anchor bolts provided. The connecting strip will auto-
matically set the bottom plate B in position;
– use a spirit level to check that the bottom plate B is
perfectly horizontal, so as to achieve proper positio-
ning and reference for laying all the water and gas
pipes in place;
– attach the small bent tube connections or the connec-
tion cocks supplied in a kit (optional);
– finally, by means of the two hex screws of the top plate
A, make the necessary adjustments to achieve perfect
vertical positioning of the boiler.
For the “MURELLE” BF versions, make a hole in the wall
sufficiently large to allow for insertion of a 130 mm ø PVC
pipe of the same length as the thickness of the wall it has
to pass through. Then fix the PVC pipe in place using
cement mortar. The purpose of the PVC pipe is to facili-
tate insertion of the coaxial air-intake flue-discharge
assembly with its corresponding external gasket, as
described in Section 2.6.1.
2 General requirements for installation
Fig. 5

7
2.5 CONNECTING UP “MURELLE” FLUE
The flue for expulsion into the atmosphere of the products
of combustion from natural draught appliances must
meet the following requirements:
– be gas-tight to the products of combustion, waterproof
and thermally insulated;
– be built of materials suitable for resisting over time nor-
mal mechanical stresses, heat, and the action of pro-
ducts of combustion and their possible condensates;
– follow a vertical path and not present any throttling
throughout its entire length;
– be adequately insulated to prevent phenomena of
condensation or cooling of fumes, in particular if loca-
ted outside the building or in unheated ambiences;
– be set at an adequate distance from combustible or
easily inflammable material by means of an air gap or
suitable insulating material;
– have beneath the mouth of the first smoke duct a
chamber for collecting solid material and any conden-
sate; the height of the chamber must be at least 50
mm. Access to the chamber must be guaranteed by
means of an opening provided with an air-tight metal
door;
– have a circular, square, or rectangular internal cross
section; in the case of square or rectangular sections,
the corners must be rounded off with a radius of not
less than 20 mm. However, hydraulically equivalent
cross sections are allowed;
– be equipped with a chimney-pot at the top, which
must be outside the so-called back-flow zone, so as to
prevent the formation of back-flow, which prevents
free discharge of the products of combustion into the
atmosphere;
– be devoid of mechanical means of suction located at
the top of the pipe;
– no overpressure should be present in a chimney that
passes within or close up to inhabited rooms.
Fig. 6 refers to the connection of the boiler to the flue or
chimney through smoke ducts. When making the con-
nection, in addition to respecting the dimensions given,
you are recommended to use gas-tight materials capable
of resisting over time mechanical stresses and the heat of
smokes. At any point along the smoke duct, the tempe-
rature of the products of combustion must be higher than
dew point.
More than a total of three changes of direction must not
be made, including the inlet connection to the
chimney/flue. For any changes of direction use only cur-
ved lengths of pipe.
Fig. 7 shows some applications of draught terminals that
ensure proper expulsion of products of combustion in
case of discharge through the wall.
SLOPE
min. 3%
2.500 mm max.
SLOPE
min. 3%
SLOPE
min. 3%
Fig. 6
Fig. 7

2.6 “MURELLE BF” COAXIAL AIR INLET-FLUE
OUTLET ASSEMBLY
The air inlet-flue outlet assembly is supplied apart (optio-
nal) in a kit (Code 8084802). It includes:
– coaxial duct ø 60/100, length 840, with wind-proof
(anti-blowback) head already fixed to the flue dischar-
ge duct;
– pipe bend ø 60/100 with fixing screws;
– fixing clamp;
– rubber ring nut for external closing;
– sponge-rubber gasket.
2.6.1 Assembly of the coaxial duct kit
For assembly follow closely what is indicated in Fig. 8.
– Make a hole in the wall sufficiently large to allow for
insertion of a 130 mm ø PVC pipe of the same length
as the thickness of the wall it has to pass through.
Then fix the PVC pipe in place using cement mortar.
WARNING: When cutting the pipe, remember that
the 60 mm ø flue discharge pipe must be approx.
25 mm longer than the air intake tube.
– Before sliding the pipe into the hole made in the wall,
insert the rubber sealing ring (E) into its seat made in
the tube.
– Push the tube outwards until the gasket comes out. Pull
the pipe inwards bringing the ring to rest on the wall.
– Slide the inner ring (D) and the metal collar (I) onto the
pipe.
– Push the flue discharge duct (F) fully home in the bend
and fasten the metal collar (I) in position, tightening the
two fixing screws.
– Fasten the duct (C) by tightening the two screws (H) on
the aluminium ring nut (D).
NOTE: The air intake-flue outlet assembly must slope
gently downwards to prevent rain water getting into
the boiler.
2.6.2 Coaxial air intake-flue outlet assembly
accessories
In addition to the coaxial duct kit, also the following can
be supplied on request (Fig. 9):
– Extension ø 60/100, length 855 (Code 8084800)
– Supplementary 90° pipe elbow ø 60/100 (Code
8085600)
–
Vertical extension ø 60/100, length 590 (Code 8086900).
NOTE: With the pipe bend supplied in the kit, the maxi-
mum length of piping should not exceed 3 metres. In
the case where the supplementary bend (4) is used, the
total length of piping can reach a maximum of 1.6 m.
When the vertical extension (3) is used, the terminal
part of the pipe must always come out horizontally.
8
KEY
1 Coaxial duct kit
2 Extension L. 855
3 Vertical extension L. 590
4 90° supplementary elbow
Fig. 8
Fig. 9
KEY
A Elbow flange
B Junction collar
C Outer duct
D Aluminium ring
E Rubber sealing ring
F Inner duct c/w terminal
H Fixing screw
I Protective metal collar
J Inner “O” ring

9
2.6.3 Positioning the outlet terminals
The outlet terminals for forced-draught appliances may
be located in the external perimeter walls of the building.
To provide some indications of possible solutions, Table
5 gives the minimum distances to be observed, with refe-
rence to the type of building shown in Fig. 10.
Notes
1) Terminals below a practicable balcony must be loca-
ted in such a way that the total path of the smoke from
its outlet point from the terminal to its outlet point from
the external perimeter of the balcony, including the
height of possible railings, is not less than 2000 mm.
2) When siting terminals, where materials that may be
subject to the action of the products of combustion
are present in the vicinity, e.g., eaves, gutters and
downspouts painted or made of plastic material,
projecting timberwork, etc., distances of not less than
1500 mm must be adopted, unless adequate shiel-
ding is provided to guard these materials.
2.6.4 Coaxial duct outlet on roof
To install this type of arrangement, the following are avai-
lable as optionals:
– roof outlet terminal ø 60/100, length 1280 (Code
8091200);
– articulated-joint roof tile (Code 8091300);
– extension ø 60/100, length 855 (Code 8084804);
– supplementary 90° elbow ø 60/100 (Code 8085601);
–
vertical extension ø 60/100, length 200 (Code 8086903).
When assembling the accessories, remember that the
roof discharge terminal (length 1280 mm) cannot be
shortened and that the articulated joint of the roof tile
allows roof pitches of between 25 ° and 45°.
The tile is a plane roofing tile (1, Fig. 11) and comes fit-
ted with a shaped and folded lead panel (dimensions
160 x 440) for adaptation to the roof.
When joining the tile to the terminal, use the collar inser-
ted on the latter (3, Fig. 11), fastening it in position with
the three self-tapping screws provided.
When positioning the roof tile make sure to leave a distan-
ce of not less than 600 mm from the discharge top of the
roof-outlet terminal.
It is possible to insert up to a maximum of three
extensions and reach a maximum rectilinear distance
of 3.7 m. Should it be necessary to make two changes
of direction in the pipe development, the maximum
length of the pipe must not exceed 2 m.
Siting of terminal Appliances from 7 to 35 kW
(min. distances in mm)
A - Below openable window 600
B - Below ventilation opening 600
C - Below eaves 300
D - Below balcony (1) 300
E - From adjacent window 400
F - From adjacent ventilation opening 600
G - From vertical or horizontal soil or drain pipes (2) 300
H - From corner of building 300
I - From recess in building 300
L - From ground level or other treadable surface 2500
M - Between two terminals set vertically 1500
N - Between two terminals set horizontally 1000
O - From a surface facing, without openings
or terminals 2000
P - As above, but with openings or terminals 3000
TABLE 5
KEY
1 Tile with articulated joint
2 Lead panel
3 Collar
4 Self-tapping screw
5 Reducing
Fig. 10
Fig. 11

10
“Murelle 20 BFR-BF” models “Murelle 25 BF” model
KEY
A Discharge pipe
B Intake pipe
It is not allowed to replace SIME accessories with other
devices. Some of the connecting systems that may be
adopted are shown in Fig. 12.
2.7 “MURELLE BF” SEPARATE AIR
INTAKE-FLUE OUTLET PIPES
The sum of the development of the air intake-flue outlet
pipes enables a maximum distance of 16 m to be rea-
ched without change of direction.
When installing the pipes, follow closely the requirements
of current standards, as well as the following practical
pointers:
– the temperature on the surface of the discharge pipe,
in the portions that pass through masonry and/or
come into contact with walls should not exceed room
temperature by more than 60°C (pr EN 483);
– with direct intake from outside, when the pipe is longer
than 1 m, you are recommended to insulate the piping
so as to prevent formation of dew on the outside of the
piping during particularly severe periods of the year;
– with the outlet pipe outside the building or in cold
indoor environments, insulation is necessary to pre-
vent burner failure in starting. In such cases, provide
for a condensate-collector system on the piping.
2.7.1 Assembly of separate-pipe kit
The accessories needed for assembly are available on
request in a kit (Code 8089902). The kit includes (Fig.
13/a):
– Discharge pipe flange ø 80 mm with fixing screws and
lip seal ø 90
– Sponge-rubber gasket
– Air diverter with fixing screws (“20 BF” vers.)
– Air-intake pipe collar ø 80 with fixing screws, sectored
diaphragm ø 38 and lip seal ø 90
The sectored diaphragm ø 38 is to be used according to
the maximum head loss allowed in both pipes, as given
in Table 6.
KEY
1 Vertical extension L. 200
2 Extension L. 855
3 Tile with articulation joint
4 Roof outlet terminal
5 Supplementary 90° elbow Fig. 12
Fig. 13

11
2.7.2 Separate-pipe kit accessories
In addition to the separate-pipe kit, also available on
request are the following (Fig. 14):
– 90° pipe elbow MF ø 80 (Code 8077404);
– 90° pipe elbow MF ø 80 with intake (Code 8077407);
– extension ø 80 , length 1000 (Code 8077303);
– extension ø 80, length 130 with intake (Code
8077304);
– air-intake terminal ø 80 (Code 8089500);
– discharge terminal ø 80 (Code 8089501);
– locking junction for separate flue kits ø 80 (n° 5) (Code
8092700);
– int.-ext. ring kit ø 80 (Code 8091500);
– 45° elbow MF ø 80 (Code 8077406);
– condensation outlet ø 80 (Code 8092800).
The distance between the boiler and air-intake or flue-
outlet point is not fixed, but must be determined accor-
ding to the particular case by adding together the head
losses of both pipes. To make the calculation, take into
account the following parameters:
– for every metre of pipe ø 80 (intake or outlet), the ave-
rage head loss is 0.21 mm H2O;
– for every pipe bend ø 80, the average head loss is
0.35 H2O.
NOTE: The maximum head loss allowed for both
pipes (intake and outlet) must not exceed 5 mm H2O.
Example:
Assuming that the length of each pipe is 4 metres, and 2
bends are made, the head loss will be
8 metres of pipe ø 80 x 0.21 = 1.68 mm H2O
2 - 90° elbows ø 80 x 0.35 = 0.70 mm H2O
Total head loss 2.38 mm H2O
With this total head loss, remove four sectors of diaph-
ragm to be used in the air-intake pipe (Fig. 13/a).
Below are illustrated some of the connecting systems that
may be adopted (Fig. 14).
Murelle 20 BF Murelle 25 BF
Sectors of diaphragm Total head loss Sectors of diaphragm Total head loss
to remove mm H2O Pa to remove mm H2OPa
None 0 ÷ 1 0 ÷ 9.8
10 ÷ 1 0 ÷ 9.8 11 ÷ 2 9.8 ÷ 19.6
21 ÷ 2 9.8 ÷ 19.6 22 ÷ 3 19.6 ÷ 29.4
42 ÷ 3 19.6 ÷ 29.4 43 ÷ 4 29.4 ÷ 39.2
63 ÷ 4 29.4 ÷ 39.2 64 ÷ 5 39.2 ÷ 49.0
Remove diaphragm 4 ÷ 5 39.2 ÷ 49.0 Remove diaphragm 5 ÷ 6 49.0 ÷ 58.8
TABLE 6
KEY
1 Blind flange
2 Outlet pipe flange
3 Self-tapping screw
4 Sponge-rubber gasket
5 Air-intake pipe collar
6 Sectores diaphragm ø 38
7 Air deflector code 6257504
6
SECTOR OF DIAPHRAGM
Fig. 13/a

12
2.7.3 Separate-pipes roof outlet
To install this kind of arrangement, the following are avai-
lable on request:
– roof outlet terminal ø 80, length 1240 mm (Code
8091201);
– tile with articulated joint (Code 8091300);
– extension ø 80, length 1000 (Code 8077303);
– int.-ext. ring kit ø 80 (Code 8091500);
– 90° pipe elbow MF ø 80 (Code 8077404);
– locking junction for separate flue kits ø 80 (n° 5) (Code
8092700)
– air-intake terminal ø 80 (Code 8089500);
– doubler fitting (Code 8091400);
– separate-pipes kit ø 80 (Code 8089902);
– 45° elbow MF ø 80 (Code 8077406);
– extension ø 80, length 130 with intake (Code
8077304);
– 90° elbow MF ø 80 with intake (Code 8077407);
– condensation outlet ø 80 (Code 8092800)
When assembling the accessories, remember that the
roof outlet terminal (length 1240 mm) cannot be shorte-
ned and that the articulated joint of the roof tile allows roof
pitches between 25° and 45°. The tile is a plane roofing
pipe (1, Fig. 17) and is provided with a shaped and fol-
ded lead panel (dimensions 160 x 440) for adaptation to
the roof. When joining the tile to the terminal, use the col-
lar inserted on the latter (3, Fig. 17), fastening it in posi-
tion with the three self-tapping screws provided. When
positioning the roof tile make sure to leave a distance of
not less than 430 mm from the discharge top of the roof-
outlet terminal. There is the possibility of doubling the air-
intake and smoke-outlet pipes and then bringing them
back together again so as to obtain a concentric dischar-
ge by using the doubler fitting (7, Fig. 17 bis). In these
cases, when assembling, recover the silicone gasket
used on the terminal adapter (5, Fig. 17), which is to be
replaced by the doubler, and insert it into the seat made
in the doubler. For this type of discharge the sum of
the maximum rectilinear development allowed for the
pipes must not exceed 16 metres. Pipe bends may be
inserted, but remember that each bend penalizes the
rectilinear stretch by 1 m, both on the smoke dischar-
ge and on the air intake portions of piping.
When calculating the lengths of pipe, take into account
the parameters given in section 2.7.2.
Below are illustrated some of the connecting systems that
may be adopted (Fig. 17 bis).
KEY
1 Separate-pipe kit
2 90° elbow MF with intake
3 Extension ø 80
4 Outlet terminal
5 Int.-est. ring kit
6 Intake terminal
7 45° elbow MF
8 Extension ø 80 with intake
9 90° elbow MF
10 Locking junction
11 Condensation outlet ø 80
Fig. 14
KEY
1 Tile with articulated joint
2 Lead panel
3 Collar
4 Self-tapping screw
5 Reducing fitting Fig. 17

13
2.8 CHARACTERISTICS OF FEEDWATER
Where the mains water has a hardness of more than 20
- 25° Fr, the feedwater must be suitably softened both
for the hot water circuit and for the central heating cir-
cuit, so as to prevent formation of boiler scale due to
lime deposits, since this could lead to a reduced heat
exchange.
It should be remembered that even small encrustations
of just a few millimetres thick, on account of their low
thermal conductivity, cause a considerable overheating
of the walls of the boiler with serious consequences.
IT IS ABSOLUTELY ESSENTIAL THAT THE WATER USED
FOR THE CENTRAL HEATING SYSTEM SHOULD BE
TREATED IN THE FOLLOWING CASES:
– very extensive system (with high contents of feedwa-
ter)
– frequent addition of makeup water into the system.
Should it be necessary to empty the system either par-
tially or totally, the subsequent refilling should be carried
out using suitably treated water.
2.9 WATER FAILURE SAFETY DEVICE
The boiler is equipped with a water pressure switch set at
0.6 bar (1, Figs. 3 - 3/a), which goes into action, blocking
boiler operation, whenever the pressure inside the boiler
is less than the calibration value.
When the pressure switch trips, a red warning lamp lights
up (7, Fig. 18).
To restore burner operation, turn the charge cock and
bring the pressure back to between 1 and 1.2 bar.
2.10 SYSTEM FILLING
Filling of the boiler and the system is done by opening the
ball cock located on the underside of the boiler (Fig. 16)
and the charge cock located on the fixing jig in the “20 R
CE IONO” version. The charge pressure, with the system
cold, must be between 1 and 1.2 bar. During system filling
you are recommended to keep the main switch turned
OFF. Filling must be done slowly so as to allow any air
bubbles to be bled off through the air valves.
Should system pressure drop during operation, as a result
KEY
1 Separate-pipes kit
2 90° elbow MF with intake
3 Extension ø 80
4 Int.-est. ring kit
5 Intake terminal
6 Locking junction
7 Doubler fitting
8 Tile with articulated joint
9 Roof outlet terminal ø 80
10 45° elbow MF
11 90° elbow MF
12 Extension ø 80 with intake
13 Condensation outlet ø 80
Fig. 17 bis

14
of gases dissolved in the water, to values of less than 0.6
bar, the burner will go out automatically, and the warning
light (7, Fig. 18) will start flashing to recall the User’s atten-
tion. The charge cock must be opened to bring the pres-
sure back up to 1-1.2 bar, as indicated on the hydrometer.
Once the pressure is restored, the warning lamp will turn
off automatically and the boiler will start up again. After
carrying out this operation, check that the cock is closed.
Should the pressure have risen well above the limit expec-
ted, discharge the over pressure by opening the pressure-
relief valve on any of the radiators.
2.11 “MURELLE 20 TX CE IONO” BOILER SUPPLY
The boilers are shipped in two separate packages:
1) Boiler and 90° elbow, and 2) Smoke discharge pipe ø
60, length 600, with rubber ring for external closing and
terminal with anti-blowback (wind-protection) device.
The following optionals are also available:
– discharge pipe extension ø 60, length 1000 (Code
8077302);
– 90° elbow ø 60 (Code 8077403);
– extension ø 60, length 125, with fume intake (Code
8077305).
By turning the 90° elbow, it is possible to orient the boiler
smoke outlet in any direction (Fig. 17)
2.11.1 Installation of “MURELLE 20 TX CE IONO” boiler
To install the boiler, proceed as follows (Fig. 17/a):
– once you have chosen the position for the dischar-
ge pipe (1, Fig. 17), make a hole ø 80 in the
masonry;
– adapt the length of the outlet pipe to the actual thick-
ness of the wall. With the extensions supplied on
request, it is possible to reach a maximum useful
length between the appliance and the external wall
surface of 3 m;
– mount the rubber ring and the terminal with wind-pro-
tection device on the pipe.
KEY
1 Outlet pipe
2 Extension Ø 60 L. 1.000
3 90° elbow Ø 60
4 Extension ø 60 L. 125 with smoke intake
OPEN
Fig. 16 Fig. 17
Fig. 17/a

15
2.12 ELECTRICAL CONNECTION
The boiler is supplied with an electric cable. Should this
require replacement, it must be purchased exclusively
from SIME. The electric power supply to the boiler must
be 230 V - 50 Hz single-phase through a fused main swit-
ch, with at least 3-mm spacing between contacts. You
are recommended to install a room temperature thermo-
stat to ensure better regulation of temperature and
comfort of indoor ambience.
This thermostat must be Class II, in compliance with the
Standard EN 60730.1.
NOTE: SIME declines all responsibility for injury or
damage to persons, animals or things, resulting from
the failure to provide for proper earthing of the
appliance.
2.12.1 Electric switchboard
To gain access to the switchboard inside the appliance,
unscrew the two screws that fasten it to the rear panel (2,
Fig. 27). The switchboard will tilt downwards at an ade-
quate angle to enable easy access to the components.
KEY
1 Room stat socket
2 Smoke safety stat
(except “20 TX-BF” versions)
3 Wired connector J3
4 Wired connector J4
5 Wired connector J5
6 FM 11 programmer (“IONO” versions)
7 Water failure warning light
8 Equipment lock out reset
(“IONO” versions)
9 Wired connector J6
10 Wired connector J2
11 Wired connector J1
12 “Summer/Winter switch
(except “20R-BFR” versions)
13 Main switch
14 Capacitor 1,5 µF (“20 BF CE” version)
15 Electric ignition (“20 BF CE” versions)
16 EMC filter (“IONO” versions)
“Murelle” series
“Murelle BF” series
Fig. 18

16
KEY
LLine
N Neutral
IG Main switch
TA Room stat
SM Heating flow sensor (blue)
F1 Fuse (T1,6A)
F2 Fuse (F50 mA)
A FM 11 programmer
EA Ignition electrode (orange)
ER Sensing electrode (white)
EV1 Gas valve coil
EV2 Gas valve coil
TS 100°C safety stat
R Equipment lock out reset button
TL 85°C limit stat
M Modulator
P Circulation pump
TF Smoke stat
PA Water pressure switch
LS Insuff. water pressure warning lamp
FA EMC filter
KEY
L Line
N Neutral
IG Main switch
E/I Summer/ Winter switch
TA Room stat
SS D.H.W. sensor (red)
SM Heating flow sensor (blue)
F1 Fuse (T1,6A)
F2 Fuse (F50 mA)
VG Gas valve
TS 100°C safety stat
TI Interrupted thermocouple
TL 85°C limit stat
M Modulator
VP Pressure switch valve
P Circulation pump
TF Smoke stat
PA Water pressure switch
LS Insuff. water pressure warning lamp
NOTE: The room stat must be connected to the terminals 40-41 of the
three-pole terminal strip after removing the link.
NOTE: The room stat must be connected to the terminals 40-41 of the
three-pole terminal strip after removing the link.
2.12.2 “MURELLE 20R CE IONO” wiring diagram
2.12.3 “MURELLE 20 CE” wiring diagram
Fig. 19
Fig. 20

17
KEY
LLine
N Neutral
IG Main switch
E/I Summer/Winter switch
TA Room stat
SS D.H.W. sensor (red)
SM Heating flow sensor (blue)
F1 Fuse (T1,6A)
F2 Fuse (F 50 mA)
A FM 11 programmer
EA Ignition electrode (orange)
ER Sensing electrode (white)
EV1 Gas valve coil
EV2 Gas valve coil
TS 100°C safety stat
R Equipment lock out reset button
TL 85°C limit stat
M Modulator
VP Pressure switch valve
P Circulation pump
TF Smoke stat
PA Water pressure switch
LS Insuff. water pressure warning lamp
FA EMC filter
KEY
LLine
N Neutral
SM Heating flow sensor (blue)
LS Insuff. water pressure warning lamp
PA Water pressure switch
IG Main switch
F1 Fuse (T 1.6A)
F2 Fuse (T 50mA)
TA Room stat
P Circulation pump
A FM11 programmer
EA Ignition electrode (orange)
ER Sensing electrode (white)
EV1 Gas valve coil
EV2 Gas valve coil
TS 100°C safety stat
R Equipment lock out reset
PF Smoke pressure switch
V Fan
TL 85°C limit stat
M Modulator
FA EMC filter
NOTE: The room stat must be connected to the terminals 40-41 of the
three-pole terminal strip after removing the link.
NOTE: The room stat must be connected to the terminals 40-41 of the
three-pole terminal strip after removing the link.
2.12.4 “MURELLE 20 CE IONO - 25 CE IONO” wiring diagram
2.12.5 “MURELLE 20 BFR CE IONO” wiring diagram
Fig. 21
Fig. 22

18
KEY
L Line
N Neutral
SS D.H.W. sensor (red)
SM Heating flow sensor (blue)
LS Insuff. water pressure warning lamp
PA Water pressure switch
IG Main switch
F1 Fuse (T 1.6A)
F2 Fuse (F 50mA)
TA Room stat
E/I Summer /Winter switch
VP Pressure switch valve
P Circulation pump
PVG Gas valve microswitch
A Electric ignition
PF Smoke pressure switch
C Fan capacitor
V Fan
TL 85°C limit stat
VG Gas valve
TS 100°C safety stat
TI Interrupted thermocouple
M Modulator
KEY
L Line
N Neutral
SS D.H.W. sensor (red)
SM Heating flow sensor (blue)
LS Insuff. water pressure warning lamp
PA Water pressure switch
IG Main switch
F1 Fuse (T1,6A)
F2 Fuse (F 50 mA)
TA Room stat
E/I Summer/Winter switch
VP Pressure switch valve
P Circulation pump
A FM11 programmer
EA Ignition electrode (orange)
ER Sensing electrode (white)
EV1 Gas valve coil
EV2 Gas valve coil
R Equipment lock out reset button
PF Smoke pressure switch
V Fan
TL 85°C limit stat
TS 100°C safety stat
M Modulator
FA EMC filter
NOTE: The room stat must be connected to the terminals 40-41 of the
three-pole terminal strip after removing the link.
NOTE: The room stat must be connected to the terminals 40-41 of the
three-pole terminal strip after removing the link.
2.12.6 “MURELLE 20 BF CE” wiring diagram
2.12.7 “MURELLE 20 TX CE IONO - MURELLE 20/25 BF CE IONO” wiring diagram
Fig. 23
Fig. 24