PIDs are great for espresso boilers where you want water around 202F (sea level), so below boiling. My home machine with an 800ml brew boiler stays within +&#x2F;- 2F all day with the PID. My previous machine without PID could barely keep it in a +&#x2F;- 5F range.<p>For steam boilers, pressure stats are actually quite effective, especially as they get larger.