Electrical Connections; Settings And Adjustments - Sit 824 NOVA Instructions

Thermocouple connection
Connect the thermocouple to the magnet unit making sure that the fixing nut is of appropriate size.
Connection to the combustion chamber (optional)
If the valve feeds a pressurized combustion chamber, it should be connected to the pressure regulator (threaded
outlet at the bottom of the valve). In this case, the use of accessory 0.958.057 or 0.958.058, including a suitable nipple
for tube ø 4 mm connection, is recommended (torque 1 Nm). The choice betwen the two accessories depends on the
specific characteristics of the appliance.
IMPORTANT: After making the gas connections, check for gas lekeage.

ELECTRICAL CONNECTIONS

General precautions
All electrical connections must be made in accordance with current electrical standards. Check that the supply
voltage and frequency conform with those specified on the valve label. Check that all connections, in particular the
earth, are made properly. With the versions powered by mains voltage, the electrical connections must be made using
suitable connectors. In particular, to ensure that the valve is always connected to the earth circuit of the appliance, it
is necessary for the EV power connector, which includes the earth terminal, to be used at all times and the screws
protected against slackening. The 24 Vac versions must be powered by an insulating transformer (at very low safety
voltage in accordance with EN 60742). To connect these versions, use terminals AMP 6.3x0.8 DIN 46244 as an
alternative to the connectors. Make the connections as specified in the specific standards for the appliance. All the safety
shut-off devices (for example the overheat thermostat and so on) must cut off the power supply to the magnet unit.
Step modulating device (824 NOVA)
The step modulating device must be
supplied with rectified full wave AC.
For this purpose the use of connector type
V~
350, with integral rectifing circuit, is
recommended. Alternatively the supply
circuit of the step modulating device must
SMD
include a diod bridge and a protective
damping device (e.i. VDR) in accordance
with current and voltage values.

SETTINGS AND ADJUSTMENTS

All adjustments must be made on the basis of the specific characteristics of the appliance. Check inlet and outlet
pressure using the pressure test points provided. After testing, carefully seal test points with the provided screws.
Recommended torque: 2.5 Nm.
Adjustment of the outlet pressure
Maximum pressure
Power the modulating solenoid with the correct maximum voltage. In alternative keep the internal moving plunger of
the modulator pressed down by inserting a 2 mm pin in the hole (D). Turning the nut (B) clockwise (using a 10 mm
spanner), the outlet pressure increases.
Minimum pressure (adjust only after setting the maximum outlet pressure)
Turn off power supply to modulating solenoid.
Keeping nut (B) blocked using a spanner, turn the screw (A) clockwise to increase the outlet pressure.
After completing the adjustments:
- check the minimum and maximum pressure values: readjust if required
- Fit the plastic cap (C)
Adjustment of gas flow to the pilot burner
Turn the "Pilot" screw clockwise to reduce flow.
IMPORTANT: At the end of all setting and adjustment operations, check electrical insulation, gas seals and the
efficiency of the appliance. After carrying out all adjustments, fit the provided seals and/or block the setting screws
with paint, taking care not to obstruct the orifice of the pressure regulator.
MAINTENANCE
The only maintenance operations permitted are the replacement of the magnet unit and of the coils of automatic shut-
off valve and modulating device. This operations must be carried out by qualified personnel only and according to the
instructions provided with the spare parts.a
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