With Singer Down-Flo electric heaters, does it matter if polarity of wire connect is reversed (not marked) ?

I am not an electrician. But it sounds like a disaster of some scale waiting to happen. Ask an expert.

It's 220 volts is it 2 wire With Ground. If so Dosen't Matter 120v on Each Leg.

polarity makes all the difference.

that's why plugs are made the way they are now days.

keeps things from malfunctioning and burning up, shorting out.

it's the optimal performance you see... not having it polarized correctly can really shorten the life of things or operate using more power than nessesary or fluctuate...

i didn't think it mattered for the longest time but i lost alot of junk over the years and burned out a many of things because i reversed it.

i wager i'm contained in the minority the following and likely residing on borrowed time, yet mine became put in even as the abode became outfitted 40 2 years in the past and that is nonetheless going sturdy. I did ought to interchange between the heating factors possibly 20 years in the past at a minor fee. also i latterly had my (chilly water) tank pressure recharged and the technician said the water furnish from my very deep nicely became very sparkling, even even though it really is quite puzzling water.

I don't know your heater but the two hot lines carry 110V each. It's single phase so you could interchange them at the breaker. Wouldn't make a difference.

Probably makes no difference, you should be able to tell if it is working correctly, if not switch the wires.

It should not mater. Polarity matters most for electronics to perform their best