27
– remove the pilot burner (8), and replace the pilot
nozzle (4);
– slide out the burner unit (11);
– replace the main nozzles (12) located on the burner
manifold (9), inserting the copper washer (10). Use a
ø 7 spanner to perform this operation;
– reassemble all the parts, proceeding in reverse order.
–
In the versions equipped with the V4600N gas
valve replace the cylindrical spring (Fig. ) of the
modulator with the red painted one supplied with
the conversion kit.
– remove the “L.P.G.-MET” connector link on the card
(10, Fig. 25) and set it on “L.P.G.”;
– to set the values of maximum and minimum gas pres-
sure, follow the instructions given in Section 3.4,
according to the type of gas valve used.
Except for making the setting, it is not necessary to
perform any other operations on the valve modulator;
– the gas feed pressure must under no circumstances
exceed 50 mbar;
– after have ultimated the conversion of the boiler, please
stick onto the casing panel the plate showing the relevant
feeding gas which is included into the conversion kit.
NOTE: After assembling all the gas connections, a
test for gas tightness must be carried out using
soapy water or special products. DO NOT USE
NAKED FLAMES.
3.8
FILTER ON GAS PIPE
The gas valve used on the
“MURELLE”
boilers is fitted
standard with an inlet filter, which, however, is not able
to entrap all the impurities in the gas or in gas mains
pipes.
To prevent malfunctioning of the valve, or in certain
cases even to cut out the safety device with which the
valve is equipped, install an adequate filter on the gas
pipe.
3.9
CLEANING AND MAINTENANCE
At the end of each heating season, it is essential to have
the boiler thoroughly checked and cleaned out.
Proceed as follows:
– turn the main switch off to stop electric power rea-
ching the boiler and close the gas feed cock;
– disassemble the outer casing as described in section
2.19;
– remove the smoke chamber, unscrewing the fixing
screws;
– disassemble the gas burner manifold unit, as descri-
bed in Section 3.7;
– to clean the burner, blow in a jet of air, so as to remove
any dust particles that may have accumulated;
– clean the heat exchanger, removing any dust or resi-
due from combustion;
– when cleaning the heat exchanger or the burners,
chemical products or steel brushes MUST NOT BE
USED;
– make sure that the tops of the burners with the holes
are free from encrustations;
– during burner disassembly and assembly, be very
careful not to exert force on the delicate items, such
as the tip of the thermocouple or the ignition and sen-
sing electrodes;
– reassemble the items removed from the boiler, making
sure to follow the correct sequence;
– check the chimney to make sure that the flue is clean;
– check operation of the equipment and/or the pilot bur-
ner and main burner;
– do not use abrasive products for cleaning the control
panel;
– after assembly of all the gas connections, these must
be tested for soundness, using soapy water or appro-
priate products. DO NOT USE NAKED FLAMES.
Preventive maintenance and checking of efficient
operation of equipment and safety devices must be
carried out exclusively by authorized technical per-
sonnel.
KEY
1 Swivel connection 1/2”
2 Locknut 1/2”
3 Pilot pipe ø 6
4 Pilot nozzle
5 Ignition plug
6 Interrupted thermoc.
7 Hex screw TE M5 x 10
8 Pilot burner
9 Burner manifold
10 Washer ø 6,1
11 Burners
12 Nozzle
13 Screw TCB M4 x 6
Fig. 35
Fig. 36
LEGENDA
1 Locking nut M13
2 Cylindrical spring
3 Maximum adj. pressure union
4 Minimum adj. pressure screw
5 Modulator 24 V
6 Retaining spring
7 Plastic cap with screw
