This also applies to bad test result for Vacuum Leak test
Follow tubes, look for possible breaks that can cause leaks.
Clean tray rubber
Clean bottom of the chamber where the rubber touches
Start a program with vacuum
When vacuum level reaches top (1-2 minutes) start observing the vacuum value.
Test 1: Push the table with your hand, if the problem is here clean more or change rubber
Test 2: If you have recently changed the heater or did any work on inside the chamber, open it again, clean it, when vacuum starts, apply force with your hand and push it. Tighten it.
If there is a problem reaching the top vacuum level, also check with a different known vacuum pump to see if the problem is with the vacuum pump.