Outdoor Power Equipment and Small Engines - How much psi do I need to get painted deck back to bare wood

I am planning to pressure wash my deck and hope to get down close to the bare wood so I can restain it. How much PSI do I need to accomplish this?

There's no way to know. It depends on what kind of paint and how well it is adhered to the wood. It will take as much psi as it takes (that's no help). Also, pressure washing wood like that usually damages the wood. It makes the grain fuzzy and weathers it badly. I don't think you'll be able to successfully do this to a level of satisfaction.

I agree with Cheese, depends on how many previous coats of paint/stain there are, how well they are sticking to each other, how thick each coat is, what kind of wood it is, the condition of the wood. And ultimately to pressure wash off multilayers of paint and stain will indeed damage the wood, plus drive moisture deep into the wood's pores that you will have to wait several days for it to dry out enough to repaint or stain. Is the current layer peeling or flaking? Is there a reason that you want to remove it all down to bare wood?