Bought a 3750 Dewalt 4 GMP power washer. Primarily I bought this machine for a few commercial sidewalks and for my lawn equipment / personal toys. I was interested in expanding towards my lawn clients, and I experimented washing my best friends house for fun. The question I would like to ask you experts is 1) my house chemical was a fleet farm "house/ brick" formula heavy duty detergent ,and it worked fine but I was not sure what tip nozzle you used after you applied it to the house and washed it off. Also after I had been over the house I found water spots of yellow on the cream color vinyl after repeated washing (Due to maybe not being close enough to the siding? ) I used the white 40 d nozzle, but wasn't sure how far to stand away from the house. I would say I was 7 to 10 feet away when washing, but never got closer than 5 feet with the white nozzle. I also used the black nozzle to rise off the detergent and it worked great as well. The white nozzle sprayed fast and ferrous, but was very misty so I wasn't sure. I was curious to know what damage you can do to vinyl siding besides the obvious of digging into it? Thanks for your patience and help !!