Lay painter's plastic over the ground at the base of the wall of wood siding to protect the surface area and capture the paint that will be removed from the wall. Set up the pressure washer by hooking the water hose and the spray hose and gun to the machine.
Put on a pair of rubber gloves and safety glasses. Wear a long sleeve shirt and pants. Pour a gallon of chemical paint stripper into a 5-gallon bucket. Place a paint-roller screen inside the bucket and hang it from the lip of the bucket. Slip a 1-inch nap roller cover over a 9-inch roller frame. Screw an extension pole into the end of the roller frame handle until it is hand tight. Dip the roller nap up and down into the stripper, rolling it multiple times on the paint roller screen to load the nap fibers with stripping agent.
Read the instructions on the label of the stripper to see how long it will need to remain on the paint before removal begins. Take the roller to one side of the wall along with the bucket. Set the bucket down and begin rolling the wall from top to bottom. Use the extension pole to get to the higher areas of the wall. Press the roller cover firmly against the wood siding surface to ensure the stripping agent covers every nook and cranny of the wall's surface. Continue loading the roller nap with chemical stripper throughout the application process. Dip the roller again after every 5-10 square feet of wall covered.
Watch the stripper interact with the paint as the paint begins to peel and bubble away from the wall. Do not begin paint removal until waiting for the exact amount of time as instructed on the label of the stripper. Put on a pair of rain pants, a rain jacket and rubber boots. Start the engine on the the pressure washer and turn the faucet on. Point the spray wand of the washer away from the wall and pull the trigger until a steady stream of spray begins to flow. Turn toward the wall and begin pressure washing off the stripped paint. Begin at the highest part of the wall working your way downward. Keep the tip of the spray gun at least 12-18 inches away from the wall to avoid damaging the wood siding.
Turn off the pressure washer and the garden hose faucet. Pull the trigger of the gun to release the pressure off the washing hose. Roll up the plastic on the ground while keeping the peeled paint on the plastic. Throw this away. Allow the wall to dry completely. Reapply another coat of stripper if the first coat didn't completely strip off all the paint, and pressure wash again.