A foot valve is a type of check valve that only allows fluid to pass through it one way. It is used in conjunction with a pump and prevents backflow when the pump is switched off.
Such backflow would not only be counter-productive, but if the pump was restarted without water in it, it could easily burn out and have to be replaced.
Foot valves are used whenever and wherever pumping occurs including:
- Extracting water from underground wells
- Filling or draining backyard ponds and swimming pools
- Filling hi-rise cooling towers with coolant
- Pumping gas with a pneumatic pump
- Pumping waste water or emptying septic tanks
- Operating pneumatic brake lines on a commercial truck.
A foot valve is attached to the intake end of a suction hose at the bottom of the well, tank or pool. When the pump is started, a suction is created that sucks the water up through the line and the foot valve opens because of the upward pressure.
When the pump is turned off, the upward pressure ceases, the valve closes again and the water tries to return down the line to its source. But even with the weight of the water in the pipe pressing down on it, the foot valve is only capable of opening upwards not downwards, so it remains firmly shut and tightly sealed.
Foot valves are a necessary part of all pumping systems and while a good quality valve will cost you a little more, the cost of replacing damaged water pumps is far greater, making the foot valve a worthwhile investment.
PVC foot valves can be used in many applications, as they are lightweight and cost-effective. Or if your pumping job involves high temperatures or pressures, you would probably be better off with a brass or stainless steel foot valve.