Did you clean out the hose from the pressure chamber (where the float is) to the circulation pump on the front?
If not, empty the water out inside the machine.
Take the hose off and clean it out.
Ensure the larger tank on the left side has no blockages either.
Check for any leaks into the base, watch to see if the red lever is up activating the switch or if the red float is up, activating the switch.
Let me know what you find.
OK, something is making the pump run all the time so at some point the switch has to be activated.
Watch the machine.
What exactly happens when you only get the pump running?
No separate valve.
The inlet valve is at the rear.
The other valves are for the regeneration.
The blue bar on the pressure chamber is the level switch.
If it thinks it's still full of water it would suggest this switch is at fault.
When it stops and pumps with no water, is the blue bar activating the switch?
If not, when the pump is running, press the switch and release it a couple of times.
The blue bar should come out and activate the switch when it fills with water.
If it doesn't, there's something wrong in your pressure chamber.
The switch the blue bar operates is the level switch.
Unfortunately, as you've cleaned out the chamber and hose there's no logical reason for the fault you have, other than a fault in the pressure chamber.
I'll opt out of the question and open it to all again.
I'm going offline now.