Notarealsignguy
Arial - it's almost helvetica
Step down should work without any real worries but based on the stuff I have here at my shop, the controllers only switch 1 leg of the 240. Even if it did both, you would have physically removed the second and put it on the neutral so power would still be switched. Don't get me wrong here, I'm not saying I am right or that it should be done this way. That's just have I have used 120v parts in place of 240. Going back to OEM is the easiest way if the part is available. Might sting a little but theres no fiddling around required.I don't think it was nefarious, most of the parts inside the HP flatbed are Chinese. If I recall it even uses the 220 volt Chinese plug, it's not just wires.
I believe there is 120 volt on the machine in addition to the 240 volt, but the way the machine tells the vacuum to go on is by giving it power, it's an automatic on/off system not a manual one.so swapping it over likely won't work... Unless you get really fancy with the wiring.
I think the best bet is to buy a 220 to 110 step down for very cheap and to use that. The only unknown is if the flap it will complain about the suction being different or if it somehow measures the amperage/voltage to turn the vacuum power up and down
Definitely interested to see how the step-down goes, so make sure you post your reply when you get it tested!