Setup:

• Setting "Vat Explodes At High Pressure" set to false
• 1x5x5 (Tinted) Glass Vat with 24 cooled Refrigerstraytors/Blaze Burners

The vat does some weird things in this setup like pressure jumping from -101kPa to +101kPa or reaching up to 2,533.3kPa.

When the contents are pumped out of the vat and a vacuum is created, air won't enter through making/opening a vent and won't cause the pressure to be released.

Im sure thats only some strange behaviour of the vat and there is more of it.