Bob Engelhardt fired this volley in
:

I should note its a 220 system. I'm going to bet nearly all home
heating oil units are 110.

True, you aren't going to be able to buy a home-heating igniter & stick
it in. But the principles are the same.

Um... when did I plop down into a world where 110 isn't available on a
220 circuit? Didja ever notice that most electric dryers have 220V
heating elements and 110V motors?

Of COURSE you can use a 110V unit, even if you do have to _slightly_
modify the wiring of the unit.

Those oil burner igniters are available in all sorts of sizes, but the
most likely one to fit inside your footprint will be the kind provided in
"salamander" space heaters -- unless your hotwasher is one of the giant
"chimney on a wagon" varieties.

LLoyd