Can I test my sprayer with water?

Yes, you can and you should.  There is a bit of a learning curve, so testing with water first is a great way to make sure the sprayer is working properly and it’s cheaper to experiment with than paint. 

Play with the flow control, which will help you get use to the adjustment so when you add your coating, adjustments will be easier. 

Start a test pattern with the flow control at it’s lowest setting and slowly turn the flow control up until you are getting a good spray pattern.