I thought it would be fun to talk about toilets since we interact with them daily, yet, mostly ignore them and their operation. Components: water inlet diaphragm valve Tank open to atmosphere (usually covered) Level Indicator with mechanical linkage to diaphragm valve(2) Chain operated stop-check valve Bowl also open to atmosphere S-bend outlet pipe to sewer/septic system Operation During normal operation, the water level in the tank is controlled by feedback from the level indicator to the inlet valve.