Thanks guys,
My story is this: one container, 1/3 filled with boiling water constantly boiling with 240*F on a pressure gauge. then the temperature of the stove is increased, indicating on the gauge that the temperature inside the pot is 255*F. Now, I know that 255*F boiling constantly would be 15psi, what is the psi for 240*F? Should be just scaled down with t1/p1=t2/p2
{*****} <-- lid
| . . .. .|
|. . .. . | <-- gas (evaporated water)
|~~~~| <-- boiling water
````````
^--- container on stove.