Check Valve

[Kim L]

Hi,
I have an outdoor kitchen and have tied the sink drain line into my pool filter drain line. It drained fine but when the pool was backwashed, water came up through the sink drain. What type of check valve can I install that will work without a pump (just gravity). I have room to install it vertically or horizontally.

Thanks,
Kim

 

[havasu]

You'll need a one way check valve, found at a big box hardware store. Many pool supply companies also carry them. They are a bit more $, but they have replaceable internal components. You just need to know the diameter size pipe you are trying to stop the backflow.

 

[Twowaxhack]

Where does this water eventually drain to ?

 

[Kim L]

It is a little odd. The line runs from my pool filter to the front of my house to the flowerbed. A 2" PVC pipe comes out of the ground and then has two 90's and drops into another pipe going into the ground, which I assume is a main sewer line. There is about a 6-12" gap between where the pipe comes out of the ground (pool line) and dumps water into the other line. I have tied my outdoor kitchen sink line into this line since it is just grey water. I just need to install a check valve to keep the water from the filter (when it is backwashed) from finding its way up the line to my sink. There is not a pump on the sink, so the check valve will need to open with just the gravity psi from the sink drain. I hope that all makes sense.

 

[Twowaxhack]

It is a little odd. The line runs from my pool filter to the front of my house to the flowerbed. A 2" PVC pipe comes out of the ground and then has two 90's and drops into another pipe going into the ground, which I assume is a main sewer line. There is about a 6-12" gap between where the pipe comes out of the ground (pool line) and dumps water into the other line. I have tied my outdoor kitchen sink line into this line since it is just grey water. I just need to install a check valve to keep the water from the filter (when it is backwashed) from finding its way up the line to my sink. There is not a pump on the sink, so the check valve will need to open with just the gravity psi from the sink drain. I hope that all makes sense.

Sounds like a mess. You need to disconnect the two lines and install a proper kitchen sink drain.

 

[MicEd69]

I'm not sure I understand how all this is connected without a picture. So, your pool backwash going to your flowerbed?

I'm not sure this will work, but you have a vertical line at the tie-in point to the backwash line, you could try installing a swing check valve in that vertical portion upside down. That way, it would remain open allowing the sink to drain freely. Then when the pool filter would backflush, the pressure in the line would probably close the flapper of the check valve preventing the backflush water from coming into your sink. Something like this:



I just used this as an example because it says, "THIS SIDE UP" on the top part of the valve, which you would install "THAT SIDE DOWN". Any other swing check valve without a spring could be used.

With an outside sink and a backwash drain line, just realize you have the potential of dirt, sand, leaves, etc., getting into the drain. That could cause problems with the check valve operating in this unique way. But if you have it all plumbed, it might be worth a shot.