(mods: please feel free to move this if I've picked the wrong category!)

Hello knowledgeable people!
I recently bought a Rancilio classe 8 dual head machine. It was claimed to be working, but couldn't be demonstrated because it is a 20a machine and had been disconnected (used to be in a sports club). When I got it home I opened it up and had a look over it: the boiler element is basically three separate elements, so I thought I'd be able to disconnect two of them and have a machine that heats up very slowly, but will be comfortably under 10A.
When I did this, it is indeed under 10A, but.... It doesn't get to temperature. The machine draws power for a while on the one element, then it stops. I'm not sure if there is something smart in there that detects only one element is drawing power so it cuts power to all of them? Does anyone know what the control board does?

I did temporarily wire the machine into a suitable 20A circuit with all three elements connected: the machine heats up happily. I did notice that not all three elements are always powered: does the controller cycle through them, turning one off at a time or something like that?

It turns out that putting in a new 20A circuit will be prohibitively expensive, so if the machine can't be made to work on 10A, I might have to pass it on

Thanks for any suggestions!