The figure below shows the two main families of acetylcholine receptors: muscarinic and nicotinic. In structural terms, muscarinic receptors are G-coupled protein receptors, while nicotinic receptors are ligand-gated ion channels. They can be found on both sides of the synaptic cleft (presynaptic and postsynaptic).
After the pressure drops below 40 psi, the electrical switch turns on the pump and the pressure in the tank increases. Any failure in any component or loss of electricity can cause a well to suddenly stop producing water when a faucet is turned on.
WATER VALVE. The water valve can cause dishwashers to leak in two ways. Dishwashers leak from the water valve itself and the water valve can stick and causing the tub to overflow. To check this, first remove the bottom front panel. Then start the dishwasher and look at the valve. If you start to see a leak replace the valve.