I use around 200 degrees of heat. Water boils at 212 degrees unless its pressurized. It will remain liquid in the hoses above that but I dont know about that once it comes out of the nozzle. I haven't tried really. I put my power washer together myself. Some parts new some used. Currently using a 13hp Honda engine that I bought used for $300. I found a NEW 4000psi 4gpm pump, direct drive, for $300. Got $150 in the hose reel, $200 in hoses. Maybe $100 in tips wands and guns. I was lucky enough to find a hot water box on craigslist for $200. It was originally a steam cleaner but the pump and motor were removed from it. I converted it from 220v to 110 (you can even do 12v) and have maybe 300 or 400 dollars in that. Since I am using it as a 110 unit right now I have a small generator powering it, doesn't take much 1000 watts would probably do it, 2000 for sure since that is what I am using. I bought a NEW trailer specifically for this purpose, was $1,100 dollars. You dont need a new one or one that expensive or big. I picked up a 330 gallon cage type "tote" tank that you get from buying bulk chemicals. I payed way too much for it (i was a sucker and it was a hard to find size when I was looking) at $175 and some hose and fittings. I dont know how much that all adds up to but it have probably the equivalent of a 7 or 8 thousand dollar unit (or more) for a fraction of that.
Its a nice setup, not all flashy stainless steel wrapped up on a skid like a hydrotek but its nice.
I've got a 7gpm 3000psi that I am mating up to a thermoking 4 cylinder diesel that I also got a steal of a deal on. That will be later this year or end of this summer before I have that done tho. I got the engine for $100 but it needs a sleeve in one cylinder (engine was practically new but was removed from the reefer unit and water got in one cylinder and pitted the wall) and then cleaned up and put back together. Then I need either a clutch unit or fabricate a plate/shaft adapter to mate the engine to the pump via some pulleys. \
Anyways I love craigslist you can get many nice things needing little or no work for cheap. And you'll have a unique setup, everyone around here has alot more money tied up in a commercially built unit that is no more effective than mine and is harder to work on god forbid it ever need it.