I am using SSR with zero crossing and it makes much difference. First, I am dithering the boiler power (the power is applied to the boiler on only some AC cycl

I am using SSR with zero crossing and it makes much difference. First, I am dithering the boiler power (the power is applied to the boiler on only some AC cycles), I am basically deciding per cycle whether I want my boiler turned on for the next 1/100th or 1/120th of the second. I am already running my model about 50 times per second (not using PID) so that's ok. Being able to apply fractional power to the boiler means it is quiet and much less scale deposits. Also due to the zero-crossing control I have much less electrical noise. Turning the boiler fully-on blindly causes electrical noise which is not nice for other devices (my Baratza Sette grinder turns on spontaneusly when this happens).