Check valve
- Thread starter Devonjevon
- Start date
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You should never need a check valve if your plumbing is designed properly. Check valves are a false sencse of security and can and will fail, usually at the worst possible moment likewhen you are not home. All it takes is a grain of sand, flake of food, algae, a small snail etc to defeat it. It does not have to be a catastrophic failure, even a trickle will lead to a flood.
As long as your over flow has a standpipe and returns are close to the surface, so only a very small, easily calculated amount of water flows back to the sump, and you maintain at least that amount of freeboard or extra space in your sump, floods are not an issue. The returns are exposed to atmosphere with the slight backflow then you have an air gap, the best possible and most simple for of backflow or backsiphonage prevention there is.
Drilled holes are no better than a check valve since a bit of algae sucked into the hole, an anemone, a small fish, snail etc can also defeat them. Nothing replaces the simple air gap.
As long as your over flow has a standpipe and returns are close to the surface, so only a very small, easily calculated amount of water flows back to the sump, and you maintain at least that amount of freeboard or extra space in your sump, floods are not an issue. The returns are exposed to atmosphere with the slight backflow then you have an air gap, the best possible and most simple for of backflow or backsiphonage prevention there is.
Drilled holes are no better than a check valve since a bit of algae sucked into the hole, an anemone, a small fish, snail etc can also defeat them. Nothing replaces the simple air gap.
