This is important, notice on one side of the body there are 2 dimples in the body and on the other side only one and the flange has dimples that will fit right in to the ones on the body this is so you don't put it in backwards. Make sure you line it up right. Now put the flange on the body, line up the dimples and put the 4 bolts on the same way you took them off. Tighten all four nuts evenly there should be no gaps around the whole thing. Now turn the water back on to make sure you have no leaks. Then line the head up with the post coming out of the flange and tighten the 2 screws evenly. Then (with the power off ) replace the wires just like the old ones came off. either yellow for either yellow and the same for the red if they are being used. If you are using "Erie" zone valves The black wires are the same as the yellow wires on a Honeywell zone valve.