About two months ago I seen "sombrero cleaning systems" doing a wool casino floor. They had a almost new BL thermal wave that sounded as if it were a train derailing. I looked inside and seen the vac gage moving from 17 all the way up to 26-27hg. If it wasn't for the noises it was making I would think the gage was broken. There was also no sound of a releif valve. It sounded Like it was going to stall, blow up, and vibrate apart. They were cleaning at about 250 ft at 350 psi with a unglided ti wand. The carpet was lifting off the floor when he was pulling back on the wand. No dry strokes and it was dry in like 45 min to 1 hr. They scrub in their ps with a 175 rotary dump. They have lots of vans I haven't seen any of the others cleaning so I don't know if they run them like that on purpose.