I am going to add to that. Oliver put out a service bulletin  when they first went to closed center systems almost 40 years ago. Find out if the motor on your rake is for a closed or open center system. In plain terms you want to use as much flow and as little pressure as what is available in your system. Inclosed center you want to get close to standby pressure with very low flow. Turn it around and both systems will have heat problems. Questions?