As usual the Prof is correct. That is the only kind of heater we use, pressure sensing, that is.We set system supply bottle to 1050lbs, then purge it down to 1025-1020 at prestage. We set the "pusher" bottle to 1150, through a regulator,(set at 1025) into the supply bottle.Automatic heaters, They are great, but always check them from time to time also. I've seen the relays stick, and it really sucks when they do, if you don't catch it. And yes, we have to run a blow-off tube outside the pass compartment of our Camaro per NHRA/IHRA rules.