Do it yourself

I disconnected my thermostat and electric heaters a while ago to do some renovations. I reconnected them the exact way and now they don't work. I would say I'm pretty good at electrical, being able to make new 3 way switches, adding new lights and switches and outlets, but this one has gotten me stumped. I got a double pole 15 amp breaker feeding 120v in the white and 120v in the black for my required 240v to supply my electric heater. I tested it with and without the thermostat, and neither would cycle power to the heater. I tested the wires and got 120v in the white and 120v in the black. I connected them directly to the baseboard leads, hooked up all the required grounds, and nothing! It should be on, continuously, without a thermostat. I tested brand new heaters too, and nothing. Connected with a thermostat and nothing! Even the room that I did not touch, that heater does not work now. I know I got 240v cycling into the thermostat, and turned it all the way clockwise to get it to turn on and nothing. For the life of me I can't figure out what the ^%$*%$ went wrong!