25
4.1
GAS VALVE (fig. 14)
The boilers are equipped standard with the
SIT 845 SIGMA gas valve (fig. 14).
The gas valve is set at two pressure values:
maximum and minimum.
According to the type of gas being supplied,
these correspond to the values given in
Table 7
.
The gas pressures at the maximum and
minimum values, are factory and should
not require adjustment.
Only a conversion to another gas( natural
gas to LPG) should the gas valve be adju-
sted.
4.2
GAS CONVERSION (fig. 15)
This operation must be performed by
authorised personnel using original Sime
components.
To convert, perform the following opera-
tions (fig. 15):
– Close the gas cock. and isolate the boi-
lers electrical supply
– Disassemble the burner manifold (3).
– Replace the main nozzles (6) supplied in
a kit, inserting the copper washer (4).
Use a ø 7 spanner to perform this ope-
ration.
– Configure the new fuel as indicated in
point 4.2.1
– For calibrating the maximum and mini-
mum gas pressure values, see point
4.2.2.
– Fix the label to the data plate showing
the new gas configuration.
NOTE: Ensure that on reassembly all seals
are replaced as required, and the tight-
ness tested, using a suitable leak detec-
tion fluid.
4.2.1
New fuel configuration
Access the parameters section by pres-
sing the control panel keys (
and
) at
the same time for 5 seconds.
The red LED flashes and the display shows:
Scroll the parameters using
or
.
To enter the fuel configuration paramater
PAR 01, use
or
.
The set value
flashes
and if the boiler in
question is a
30 HE -EV
with methane, the
display shows:
4
USE, MAINTENANCE (including BENCHMARK) AND COMMISSIONIG
3
4
2
1
5
6
Fig. 15
KEY
1 Swivel connection 1/2”
2 Locknut 1/2”
3 Burner manifold
4 Washer ø 6.1
5 Burners
6 Nozzle M6
7 Screw
WARNING: To ensure a
perfect seal, always use
the washer (4) supplied in
the kit when replacing
nozzles.
KEY
1
Modulator
2
EV1-EV2 coils
3
Pressure inlet upstream
4
Pressure inlet downstream
5
VENT pressure
TABLE 7
Burner
Modulator
Burner
Modulator
Type of gas
max. pressure mbar
current
min. pressure mbar
current
25 HE -EV
30 HE -EV
mA
25 HE -EV
30 HE -EV
mA
SYSTEM 25 HE -EV
SYSTEM 25 HE -EV
G20 *
11.5
11.7
130
2.0
2.1
0
G30
28.5
28.5
165
4.8
5.0
0
G31
36.5
36.5
165
4.8
5.0
0
(*) Max. burner pressure is guaranteed only when the working gas supply pressure, tested at the upstream
pressure test point (3), exceeds the max. burner pressure by at least 3 mbar.
Fig. 14