First what speed are you running you unit on? What temps are you getting on that speed? Also do you need to preheat the blower for 10-15 minutes by blocking off the vac port before every job just to get that heat?
Going from memory, and I'm not the mechanic, I believe we initially run the Pro-1200 without a load up to 1,500 RPM, then we block the vacuum and set the vacuum release at 14 of lift. That would be for the high speed, per the factory specifications, which gives us about 1,400 RPM (maybe a tad more) while cleaning.
The middle speed is about 1,250 RPM and the low would be 1,000 RPM or so.
Since we know that every carpet cleaner is different, when we bring them in for the first 50-hour service check, we'll ask follow up questions on how the Pro-1200 is performing. Some cleaners are strictly commercial, so a higher middle speed helps them on medium length single runs, using the high speed for extra long runs or running dual wands.
We can customize the speeds through the idle control module, per the feedback we're getting from the customer, but we do stay within the
Sapphire guidelines.
The heat is indead a factor of the RPM and vacuum load plus the ambient temperature. Cleaning my apartment in winter, oh sure I was barely above 200*F (it was bitter frozen tundra weather) but last summer, it was a solid 235*F, I was running on high though.
In as far as preloading, our guys fire up the machine with the wand in a corner (so the vacuum is blocked) and by the time they're done moving furniture, the machine is getting up to heat. On successive jobs, the machine has heated up, it doesn't take long at all, the guys just start cleaning and within a couple of minutes, they're at high temperatures.
I'm just trying to be supportive, once you get past the intial tweeks, the Pro-1200 won't require any fussing around with for a very, very long time. Oh yes, before I forget, for accurate temerature readings on the gauge, you need to be on the trigger of the wand, flowing water past the temperature sensor.
I'm going to book mark this thread, will check in later for you.