GAS REGULATOR PRESSURE SWITCH
Control and regulate the steam pressure in the boiler, increasing or decreasing the burner flame according to the
steam boiler pressure.
The pressure changes act on a rubber membrane, which triggers the regulating valve. This opens and closes
the main gas passage.
In addition to the main gas passage, a smaller passage permits a small quantity of gas to circulate, even when
the main passage is closed.
NOTE: Periodically tighten (2 or 3 full rotations) the screw of the smaller passage so as to keep the passage
clear, as it tends to get obstructed by residue from the gas flow.
Adjustment of the gas pressure switch ( Fig. B ), starting with the machine cold and without pressure
a) Fill the boiler with water.
b) Loosen the nuts (4a) and (5a) completely tighten the screw (4) of the smaller passage of the gas
regulator pressure switch and loosen the calibration screw (5).
c) Turn on the power sources.
d) When the pressure reaches 0.2 bars, less than the desired value for the calibration (normally 1 bar for
semi-automatic machines and 1.4 for lever machines) of the gas regulator pressure switch, disconnect
the electrical resistance, keeping the gas burner lit.
1st If the gas regulator pressure switch is correctly calibrated, the gas flame will go out when the water
from the boiler pressure gauge reaches the desired value.
2nd If the gas flame goes out at a lower value than desired, loosen the screw (5) and turn on the burner
again. Repeat the procedure until the flame goes out when the pressure gauge reads the desired
pressure.
3rd If the calibration is too high, the gas flame will go out at higher levels than desired. Partially
decrease the boiler pressure, tighten the screw (5) and turn the burner on again.
e) Repeat the procedure until the disconnection reaches the desired pressure, and once the procedure is
complete lock the locknut (5a).
f) Once the first phase is complete, adjust the screw of the smaller passage (4).
1st Loosen the screw of the smaller passage (4) and turn the burner on again.
2nd Gradually loosen the screw of the smaller passage (4) until the flame reaches a height over the
burner surface of approximately 10 mm.
3rd Verify that with this flame the pressure read on the pressure gauge is constant, and once the
procedure is complete lock the locknut (4a).
NOTE: Normally, if using mixed gas and electricity, calibrate the pressure gauge to 0.8 bars and the gas
regulator pressure switch to 1 bar for semi-automatic and automatic machines; in lever machines, calibrate the
pressure gauge to 1.2 bars and the gas regulator pressure switch to 1.4 bars.
VERIFICATION OF BURNER FUNCTIONING.
The flame must be blue in colour with yellowish edges.
The flame should not be far from the burner.
When the burner flame is at its minimum position, the flame should reach a height of approximately 10 mm
above the burner surface.