Everyone is concerned about Tom Brady's balls this week and everyone has a theory but they all make the same mistake. They assume that the balls were good when measured by officials and then altered. So they have to believe (as of now) that an attendant stopped at the bathroom and released the pressure in 11 of 12 balls exactly the same amount in 90 seconds.
It happened this way (if it happened at all); The balls were inflated to what Brady wanted, let's say 12.5 psi. Then the balls were heated in a hot box set to the proper temperature. As the air inside the balls heated, it expanded and the pressure rose. PV=nRT where R is a constant, T is tempature, P is pressure, V is volume, and n is the amount of air. The volume does not appreciably change but when temperature goes up the left side of the equation must also go up which leaves pressure (P). So heating the balls increases the pressure, the official looks at it, the balls are taken to the field and start to cool to ambient. When they reach ambient the pressure in the ball is back to 12.5 psi and no one had to "DO" anything involving a tool.
If you double the temperature then you double the pressure but that is not necessary. You only want to increase the pressure by 20% so you increase the temperature by 51F on the field add that to 273 to get Kelvin or 324K, increase by 64.8K or 384.8K which is (take away 273) 111.8F. So there you have it. Heat the footballs to 112 degrees and you end up with 15 psi of pressure until it cools down.