Both the Extruder and spray pump is controlled by a PVG valve.
The PVG Valve is a valve that controls the flow of the hydraulic oil. It can control forward and reverse.
We control forward, by using an electric signal. When we have a power supply at about 12 V then the control signal must be 6 V (50% of power supply) for Centre (no speed) and 3 V (25% of power supply) for full speed forward.
If you have a power supply of 14 V on the PVG the centre is at 7 V and full speed at 3.5 V.
If you do not have power on the PVG valve you can manual operate the PVG Valve by moving the handle at the PVG valve.
If the PVG valve suddenly speeds up or stop, you will need to check the cable. Maybe you can measure on the pin connection if the power is stable.
It could be a good idea to change the cable.
1 = Power supply + (12-14 Vdc)
2 = PVG Signal (3-7 Vdc)
Ground = Power Supply – (12-14 Vdc)
Other possibilities of errors:
1) The electric control unit at the PVG is faulty
2) The PVG is faulty
3) The controller of potentiometer that supplies the PVG signal is faulty