Let me see if I follow you. The unloader is unloading
when you run the surface cleaner.
Have you checked the "Spike" pressure of your system?
The spike pressure should typically be about 3300 PSI
on a 3000 PSI system. (Usually 10% over max rated pressure)
Hydrotek surface cleaners are equpped with a valve, where
you can dump some of the water instead of sending
it all to the nozzles, if you open that valve slightly it
should stop cycling.
If the unloader is properly adjusted and properly sized nozzles
are in unit, and it is cycling this would indicate an obstruction
in the system. If you were saying the unit is cycling with no nozzles,
I would suspect an obstruction in the unit somewhere. Possibly even
in the swivel.
Call me if I can help.