" wrote:
Temporarily hook it up to 120V. Turn it on and see how it works, in
terms of giving off heat. If it is meant for 240V, the heat output will
be 1/4 of its normal output, so it should be a 240V hookup. Don't try it
on 240V first, because if it is a 120V unit, running it on 240V will
cause it to put put 4 times correct output and will fry it in a few seconds.

How do you know it's operating at 1/4 of normal output if you don't know
what normal output is?