Air system slow recovery after unloading

[eb99603]

When the tanks are empty the compressor seems to fill them rather quickly. At least until 90-100PSI or so, then it's slower up to 125 where the governor cuts out. I attribute that slowness to a bunch of PR4 pressure retaining valves opening and letting air out of the tanks and into the devices. So the governor cuts out, the dryer purges, and the pressure holds pretty steady.  Use some air, and eventually we reach the compressor cut-in. The air seems to recover slower than it did when filling from empty. Does this make any sense? And how quickly should it raise the pressure?

[Jon]

That makes perfect sense. When the brake pressures are satisfied it should open the accessory side so now there is added volume to satisfy. Additionally the compressor has to work harder to deliver air at the high end of the pressure range.