Close off the water supply to the dwelling by turning the gate valve to the right side.

Next drain the tank and the supply line by opening the valve. Each installation could be different, depending on ow and where it is installed. Any installation should have a shut-off valve and a drain valve somewhere before entering the dwelling.

Loosen the 4 screws that hold the wires to the switch

The ground screw on the bottom of the switch shares the ground from the supply line and from the pump. Remove those as well.

With the wires removed from the switch and the water line drained, remove the switch from the nipple attached to the check valve. Use a suitable wrench like an adjustable or in this case a pipe wrench