50
926.116.5 - en
INSTRUCTIONS FOR FITTERS
The authorised Technical Assistance Service can convert this boiler to natural gas (
G20
) or liquid gas (
G31
).
19. GAS CONVERSION
The procedure for calibrating the pressure regulator varies slightly according to the type of gas valve fitted (
HONEYWELL
or
SIT
, see figure 10).
Carry out the following operations:
A) replace the main burner nozzles;
B) change the modulator voltage
C) new max. and min. calibration of the pressure regulator.
A) Replace the burner injectors
r DBSFGVMMZQVMMUIFNBJOCVSOFSPGGJUTTFBU
r SFQMBDFUIFNBJOCVSOFSJOKFDUPSTNBLJOHTVSFUPGVMMZUJHIUFOUIFNUPQSFWFOUHBTMFBLT*OKFDUPSEJBNFUFSTBSFTQFDJàFE
in table 2.
B) Change the modulator voltage
r TFUQBSBNFUFS
F02
according to the gas used, as described in section 21;
C) Calibrate the pressure regulator
r DPOOFDU UIF QPTJUJWF QSFTTVSF UFTU QPJOU PG B EJGGFSFOUJBM QSFTTVSF HBVHF QPTTJCMZ XBUFSPQFSBUFE UP UIF HBT WBMWF
pressure test point (
Pb
) (Figure 10). Only for models with sealed chambers, connect the negative pressure test point
of the pressure gauge to a “
T
” fitting in order to join the boiler adjustment outlet, the gas valve adjustment outlet (
Pc
)
and the pressure gauge. (The same measurement can be made by connecting the pressure gauge to the pressure test
point (
Pb
) after removing the front panel of the sealed chamber). Measuring burner pressure using methods other than
those described could lead to incorrect results as the low pressure created by the fan in the sealed chamber would not
be taken into account.
C1) Adjustment to nominal heat output:
r PQFOUIFHBTUBQBOETXJUDIUIFCPJMFSUPUIF8JOUFSNPEF
r PQFOBIPUXBUFSUBQUIBUDBOQSPWJEFBáPXSBUFPGBUMFBTU
10 litres a minute
or make sure there is maximum heat
demand;
r SFNPWFUIFNPEVMBUPSDPWFS
r BEKVTUUIFCSBTTTDSFX BVOUJMUIFQSFTTVSFWBMVFTTIPXOJOUBCMFBSFPCUBJOFE
r NBLFTVSFUIBUUIFEZOBNJDJOMFUQSFTTVSFPGUIFCPJMFSNFBTVSFEBUUIFHBTWBMWFQSFTTVSFUFTUQPJOU 1B 'JHVSF
is correct (37 mbar for propane or 20 mbar for natural gas).
C2) Adjustment to reduced heat output:
r EJTDPOOFDUUIFNPEVMBUPSQPXFSDBCMFBOEVOTDSFXUIFTDSFX
b
) until a pressure value corresponding to reduced heat
output is achieved (see tab. 1);
r SFDPOOFDUUIFXJSF
r NPVOUUIFNPEVMBUPSDPWFSBOETFBM
C3) Final checks
r BUUBDIUIFBEEJUJPOBMQMBUFTVQQMJFEXJUIUIFUSBOTGPSNFSTQFDJGZJOHUIFUZQFPGHBTBOEUIFDBMJCSBUJPOQFSGPSNFE
Figure 10
SIT valve - mod. SIGMA 845
Honeywell valve - mod. VK 4105 M
0904_0701
