220 at terminals power source to heater wired wrong need to rewire heater

Some of these heater packages come wired for 3 phase. If yours has a 3 lug connector block with 2 black on one lug, 2 yellow on one lug, and 1 black/1 yellow on one lug, simply combine the black wires on one lug, the yellow wires on another lug, and leave the third lug empty.