Question for Donald, I am looking at the jag 6.6 for carpet cleaning. I see the one you offer is 0-800 psi. Looking a pictures of this machine, I do not see a psi adjustment knob anywhere on it. Am I missing this. If There is no knob on the exterior of this machine, how is it adjusted? I am also looking at different heaters for the machine. Little giant portable gas heater is very interesting. I do 80 percent high rise condo work and run into very dirty carpets on a regular basis. Do you have anymore recommendations as far as a high output heat source that is portable? In your opinion what is the optimum temp. to clean carpets?