Most 2HP and smaller submersibles come with a check valve built in or one attached to the pump. That is the only check valve you want in the system. Any other check valve will cause problems. In many states having a check valve above ground is illegal. In states like Texas they say you must have a check valve above ground, but you cannot have any pipe under a negative pressure. Those two things do not work together. Having a check valve above ground actually makes a negative pressure in the pipe, so it it illegal even though it is required. If state regulations are so confusing, you can guess how confused most people are on this subject.
Well guys don't make a lot of money on check valves. But with the old pressure tank only method, the pump cycles on and off so much it wears out check valves quickly. So they add another check valve thinking it will spit the abuse and last longer. In reality they just need to eliminate the cycling to make the check valve and everything else last longer. But adding a CSV1A makes the pump, tank, switch, check valve, and everything else last so long, they don't like that either. So they just add an extra check valve or two and let you cycle your pump, tank, switch, check valves to death, which is how they feed their kids. And if you fall for the multiple check valves and no Cycle Stop Valves again, they also put their kids through college on your money.
