The manual explicitly states: "Clogged vacuum tubes are the #1 cause of 'Vacuum Low' error E-14."
A quick search for the PDF will return roughly 84 pages of dense information. Here is a breakdown of the most critical chapters every technician must read. Ivoclar Programat P90 Manual
When programming or checking settings, keep these standard variables in mind: : The starting temperature of the furnace. The manual explicitly states: "Clogged vacuum tubes are