They are designed to run at 11 hg. Theory being that cfm dries carpets not lift. I know some of the guys w/ big machines still prefer high lift. I haven't had enough experience w/ monster machines to know who is right. For that kind of money I am not guessing. Easier to turn down a machine w/ higher specs than to try to reengineer one w/ lower specs.
CFM does dry carpet. So why not run the relief valve tighter (creating a higher level of lift) to Prevent cfm loss at the wand? That's really the point of running higher lift settings via standard spring relief or a precision valve like a Kunkle/Bayco. Keep the airflow at the wand and not sucking out the back of the relief valve. It's simple logic that tends to be over analyzed IMO on the boards. A relief device is intended to protect the blower. Keep it within the blower specs and the load capacity of the machine and it's all smooth sailing... :wink:
I don't own one but have demoed it. Quiet machine, runs smooth at 2200 rpm. Good vac. Less sensors and wires. Its going to be the best machine Pro Chem ever built.