Minimum Gas Pressure Switch; Flame Presence Check - Riello GAS 3 P/M Installation, Use And Maintenance Instructions

6.7.3

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. 32) 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 shutdown;
– remove the pressure gauge and close the cock of the gas
pressure test point used for the measurement;
– open completely the manual gas cock.
1 kPa = 10 mbar
ATTENTION
Start-up, calibration and operation of the burner
D3855
Fig. 32
6.7.4

Flame presence check

The burner is fitted with an ionisation system to check that a
flame is present. The minimum current required for the control
box operation is 6 A. The burner supplies a significantly higher
current value, so that no check is usually needed. However, if it
is necessary to measure the ionisation current, disconnect the
plug-socket 5)(Fig. 6 a pag. 14) on the ionisation probe cable and
insert a direct current microammeter with a base scale of 100 A.
Carefully check polarities.
ATTENTION
33 GB
20156565
Fig. 33
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