My Cat pump isn’t externally plumbed so I can’t run a bypass line to my supply tank. Is there some way to take the thermal valve off and install a small orifice ‘pisser’ elbow that will keep the pump cool when off the trigger? If small enough I don’t imagine too much water will be wasted.
I think there are better options than what you’re asking. A little trickle of water might not be enough to keep your pump cool if you are off the gun for awhile. Are you saying there’s no port on your unloader to attach a bypass or don’t you have a buffer tank?
They do have what’s called a “dump gun” or something like that. When you’re off the gun will dump water at low pressure. If not running a bypass I think this is the better option because I wouldn’t want my pressure washer sitting on the trailer with water running all over the place.