Can I put a 4500 watt element and a 3500 watt element in a water heater. I have an energy smart Whirlpool 40 gal. with the circuit board on top. The reason I ask is the bottom 4500 watt element burned out and I had this 3500 watt element from a previous tank. So can I have a 4500 watt and a 3500 watt elements mixed.