Vacuum apparatus lowers the pressure above the liquid, REDUCING the boiling point (there is less pressure above so the molecules do not need as much energy to break free from the liquid) so by having a leak in the vacuum system, the boiling point has to go up because there is an increase in the atmospheric pressure above the liquid, so the molecules need more energy to break free from the liquid... This is why high altitudes need additional time to cook things, water boils at a lower temp