I am curious, so I just throw the question out for whoever cares, thanks!
The pressure from the brew boiler (~12 bar - expansion issues) acts on the solenoid piston via a ~ 1.00 mm hole. The Linea's "hole" may/may not be 1.00 mm, but close enough
12 bar = ~174 pounds per square inch
1.00 mm diameter = ~ 0.00122 square inches
Force on piston = ~0.21 lbs = ~ 3.4 ounces
When the valve assembly is screwed in place, the spring gets compressed such that its opposing force is greater than 3.4 ounces.