Cuda if that link you posted is correct, that thing should work OK on 240. It shows 5000 watts, which would be nominally 20A at 240V, or depending on blower and the way it's set up, should operate on "maybe" a 30A circuit, or maybe 40A circuit.
The thing is, electric furnace elements are usually not very "fussy." I have re-strung MANY furnace elements when I worked in the HVAC service field. Here's a typical replacement "universal" element
Notice that they are rated at 5KW at 240V, and 3.75 KW at 208V. That works out to 20 amps at 240, and less at 208V
http://www.myhvacparts.com/store/electric-furnace-re-string-kits.php
Does the nameplate label SPECIFICALLY say that it's only for 208? Some equipment is rated for 208-240
