That cheap thing will blow out, the flap will exit the chamber, and you'll be dog-paddling in your basement. There's a "This Old House" episode showing this type of preventer failing.
Back up sewer water is typically not high PSI. If it encounters an obstruction it will divert to the path of least resistance which is usually the nearest house that does not have a backwater valve. There could be a scenario where sewage water can build extreme pressure but that is very rare and usually the water at that point is coming in through other places like windows and doors.
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In Canada code is an normally open design.
That cheap thing will blow out, the flap will exit the chamber, and you'll be dog-paddling in your basement. There's a "This Old House" episode showing this type of preventer failing.
Back up sewer water is typically not high PSI. If it encounters an obstruction it will divert to the path of least resistance which is usually the nearest house that does not have a backwater valve. There could be a scenario where sewage water can build extreme pressure but that is very rare and usually the water at that point is coming in through other places like windows and doors.
What size of pvc piping
That’s true , I have 2 installed in my drainage line yet flood passes through them
Wat country this video