Gas Conversion Methods - Westen Boyler digit 240/40 Fi Manual Del Usuario

The authorised Technical Assistance Service can convert this boiler to natural gas (G20) or liquid gas (G31).
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;
• carefully pull the burner off its seat;
• replace the burner injectors making sure to fully tighten them
to prevent gas leaks. Injector diameters are specified in table 1.
Replacing the diaphragm nozzle
(for models 240/40 i - 240/60 i - 240/40 Fi and 240/60 Fi)
• remove the gas inlet hose (1 of Figure 12b);
• replace the diaphragm nozzle mounted on the gas valve (2);
• put back the gas inlet hose.
B) Change the modulator voltage
• set parameter F02 according to the gas used, as described in
section 21.
C) Calibrate the pressure regulator
• connect the positive pressure test point of a differential pressure
gauge (possibly water-operated) to the gas valve pressure test
point (Pb) (figure 12a). For models 240 i/Fi use the pressure
tap (3) in the gas inlet hose (figure 12b). 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 adjust-
ment 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
• open the gas tap;
• press (section 3.2) and switch the boiler to the winter mode;
• open a hot water tap that can provide a flow rate of at least 10
litres a minute or make sure there is maximum heat demand;
• make sure that the dynamic inlet pressure of the boiler, measured at the gas valve pressure test point (Pa) (Figure 12a) is correct (30
mbar for butane, 37 mbar for propane or 20 mbar for natural gas).
• remove the modulator cover;
• adjust the brass screw of the sleeve until the pressure values shown in table 1 are obtained;
C2) Adjustment to reduced heat output
• disconnect the modulator power cable and unscrew the red screw until a pressure value corresponding to reduced heat output is
achieved (see table 1);
• reconnect the wire;
• mount the modulator cover and seal the screw.
C3) Final checks
• attach the additional plate supplied with the transformer specifying the type of gas and the calibration performed.
INSTRUCTIONS FOR FITTERS

19. GAS CONVERSION METHODS

SIT valve
mod. SIGMA 845
Pc
Pb
Pa
Figure 12a
Figure 12b (models 240/40 i - 240/60 i - 240/40 Fi and 240/60 Fi)
45
926.008.2 - EN