Easy to check it out!  Put a length of Tygon tubing on the press input conn. Make it long enough to hold a foot or so of water, (below the port) and make a U so that you can read the diff in water levels in inches.
Connect your voltmeter to measure resistance on the leads. I expect one set will be normally open and one set normally closed. The white is probably the normally closed lead to the blue. The blue to red then will close as you blow on your water manometer to get a few inches of water diff in the water levels.
Adjust the screw to make it close at about 4" of water, which corresponds to about 95 mph.