This item was relatively easy to install. I turned off the water and since there was a vacuum I didn't have to empty the water. I screwed a 5 inch pipe into the gas inlet hole and turned counter clockwise. I had this new unit ready, taped with the teflon plumbers tape ready to go. Water will escape, but minimally. Screw the new one in hand tight, screw the pipe into the inlet and tighten the gas valve clockwise until you feel a good amount of resistance. Make it horizontal, screw the gas pipes in and hook in the control wires. Turn the gas on and check for gas leaks. Follow instructions on how to light the pilot. Good to go.