Riello GAS Series - Pressure Switch Adjustment

2915858
22
GB
Start-up, calibration and operation of the burner
6.6 Pressure switch adjustment
6.6.1 Air pressure switch “1”
The air pressure switch is set after adjustment have been made.
Begin with the switch at the lowest setting. With the burner work-
ing at the minimum output, adjust the dial clockwise, increasing
its value until the burner locks out. Now reduce the value by one
set point, turning the dial anti-clockwise.
6.6.2 Over pressure switch “2”
The over pressure switch must be set after all other adjustments
have been made. its purpose is to cause the burner to shut down
if the combustion chamber pressure increases above normal op-
erational values.
Begin with the switch at the highest setting, with the burner work-
ing at the maximum output, adjust the dial anti-clockwise, de-
creasing its value until the burner shuts down. Now increase the
value by one set point and re-start the burner. If the burner shuts
down due to the pressure surge in the combustion chamber
caused by the ignition gas, check that the start gas rate is less
than 25% of the main gas rate. If it is, increase the value on the
over pressure switch by a further half a set point and repeat the
test.
NOTE:
To comply with the Appliance Standard PREN 1020, the CO
value must not exceed 0.1% under normal operational con-
ditions.
6.6.3 Minimum gas pressure switch
The purpose of the minimum gas pressure switch is to prevent
the burner from operating in an unsuitable way due to too low gas
pressure.
Adjust the minimum gas pressure switch (Fig. 23) after having
adjusted the burner, the gas valves and the gas train stabiliser.
With the burner operating at maximum output:
– install a pressure gauge downstream of the gas train stabilis-
er (for example at the gas pressure test point on the burner
combustion head);
– choke slowly the manual gas cock until the pressure gauge
detects a decrease in the pressure read of about 0.1 kPa
(1 mbar). In this phase, verify the CO value which must al-
ways be less than 100 mg/kWh (93 ppm).
– Increase the adjustment of the gas pressure switch until it in-
tervenes, causing the burner shut-down;
– remove the pressure gauge and close the cock of the gas
pressure test point used for the measurement;
– open completely the manual gas cock.
WARNING
Check for reliable burner operation. If the burner
locks out, reduce the value by a further set point.
Fig. 22
D68
WARNING
1 kPa = 10 mbar
Fig. 23
D896