28 psi is the spec, so 30 is fine. However, while the pressure regulator is working to control the pressure, the damper is shot (the other canister in front of the pressure regulator in the return line). It should hold pressure overnight -- pressure drop can make for hard starts cold, may take a bit for the pressure to come up.
I need to test mine before winter -- also need to check the cold start system.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!