Check Accusumps installation guide - page 3 in the link provided here.
This is really ALL that is necessary for what these do. When the small amount of pressure stored in the Accusump is done... it's done! This takes very little time to bleed off. It reestablishes pressure quickly if the pump and pressure in the motor is operating properly... but it's not like you can go on driving with low oil pressure.
http://www.accusump.com/accusump.pdf/instructions.pdf