A friend gave me a "just job" to wire in his 2nd hand untested 6010E. I did just that today for him and when I test ran it with it connected to a reciever it failed to unload or shut down before reaching the max working set pressure of 8 bar.
As a sparks I really dont know a great deal about screw comps and could do with a pointer or two as to what can be the problem please.

I found the main pressure differential switch and assumed it may be faulty, as a quick and dirty test I disconnected one of the 2 wires into it, ran the comp then touched the 2 wires together, a solenoid somewhere was heard clicking when I short the pair but the comp didnt unload or shut down.

I'm unsure of the correct method that this model should follow but guess that it loads from once the star delta starter is energised, reaches set max pressure then should unload? but motor keeps running the comp unloaded until a pre set timer times out, if no air is used once the timer times out the comp shuts down, if air is drawn the comp loads up to max pressure again.
Is this the correct operation?

Thanks for any help.