Control Group

The electrical control group comprises an electrical pressure regulator, an electrically operated main shut-off valve, a pressure gauge and a pressure line filter mounted on the left front side of the machine.

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The pressure regulator is fitted with a 12 V electrical motor to allow for remote control. On the control panel, the working pressure can be raised or lowered by setting the AUTO/MAN toggle switch to manual mode (MAN) and by raising or lowering the pressure using the (+) or (-) keys. In case of emergency, the pressure regulator can be adjusted manually. Push in the knob (B) and turn to adjust the pressure. When turning in clockwise direction, the pressure will be increased. Anti-clockwise turning will decrease the pressure.

Never set the pressure higher than 15 bar, due to the maximum permissible pressure of the machine. Behind the pressure regulation there is a seperate safety valve mounted with a direct overflow into the system.

Operation of the main shut-off valve takes place from the control panel in the cab. The main shut-off valve is an electrically operated ball valve. This valve is located behind the main valve cover for standard machine (C). When the machine is equipped with the optional ring line circulation system, the valve is located at the rear side of the machine in the center frame of the boom.

When the MASTER switch "M" on the control box is in the open position, the liquid is pumped at the set pressure via the pressure line filter to the boom section valves. The flow of liquid not sprayed flows via the pressure regulator into the return line. The liquid can be returned to the solution tank or to the suction side of the pump (depends on the setting of the circulation valve).

When the MASTER switch "M" on the control box is in the closed position, the liquid is circulated at low pressure and flows back to the tank or to the suction side of the pump (depends on the setting of the circulation valve). Also refer to "Circulation Valve" in this section.

A-Pressure regulator
B-Manual pressure adjustment knob
C-Main shut-off valve location

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The spraying pressure is indicated digitally via the display of the spraying computer. For that purpose, the machine can be fitted with a digital pressure sensor (A) which is mounted to the rear centre of the spray boom.

If the spraying computer is fitted with a flow sensor (B) (extra) instead of a pressure sensor, the calculated spraying pressure will be given on the display.

Another option is that both a pressure sensor and a flow sensor are fitted to the machine, in which case the measured pressure of the pressure sensor will be given on the display. Also refer to "Operation of the spraying computer".

A-Digital pressure sensor
B-Flow sensor

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The analogue pressure gauge (A) fitted to the front of the machine is for monitoring purposes only. The pressure gauge is located near the pressure regulator and displays the pressure at the center frame of the boom (in bar). The spraying pressure given on the computer is very accurate and is always lower during spraying due to pressure losses in the line. Depending on the output, the spraying pressure at the nozzles will always be slightly lower than the pressure on the display due to pressure losses in the lines and the presence of diaphragm non-return valves in the nozzle holders. Make allowances for this when calibrating the spray nozzles.

A glycerine damped pressure gauge with a 100 mm housing and a phased scale of 0-10/25 bar is fitted on machines with flow-based regulation. The scale is divided into four color zones. Make sure the pressure is always set in the green zone (1-10 bar). From 0-10 bar, the scale is divided into steps of 0.2 bar (accuracy: 1.0% of 10 bar, i.e. 0.1 bar). Sprayers with pressure based regulation (with digital pressure sensor) are delivered with a calibration pressure gauge only (used for the calibration of the pressure sensor only). Also refer to "Testing of the Machine" in the section "Maintenance" or "Pressure Sensor Calibration" in the section "Operation of the Spraying Computer".

A-Analogue pressure gauge

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The pressure line filter (B) is important to avoid restrictions during spraying and provides the last central filtering before the liquid is moved to the nozzles.

A 50 mesh filter (red) is fitted as standard. This filter has a mesh width of 280 micron (0.28 mm) and is suitable for flat fan nozzles of the 02 type (or comparable sizes) and larger. A finer 80 mesh filter (blue) can be fitted for smaller nozzles. This filter has a mesh width of 180 micron (0.18 mm).

The filter must be cleaned regularly (in any case after each use). This can be done simply by unscrewing the filter ring (A) and removing the filter element (B) out of cup (C). Regular cleaning of the filter will prevent silting up, which could break the filter.

A-Filter ring
B-Filter element
C-Filter cup

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