Float Valve Plumbing Help

[Singlemalt]

Somehow I feel like I should have been able to figure this one out myself.

I was tired of hooking my RO unit up to my slop sink everytime I needed to fill off my top off resivoir so I bought a Kent float valve in the PA group buy and put a saddle valve on a cold water pipe. As I look at setting things up I realized that if I hook up RO input to the saddle valve and the output to the float valve the barrel won't overflow but waste water will continue to flow out of the RO.

So the question is...how can I set the float valve up to shut off the water TO the RO unit so that the waste water will stop flowing when the water level in the barrel shuts off the valve?

Thanks
Lou

 

[JohnS_323]

Somehow I feel like I should have been able to figure this one out myself.

I was tired of hooking my RO unit up to my slop sink everytime I needed to fill off my top off resivoir so I bought a Kent float valve in the PA group buy and put a saddle valve on a cold water pipe. As I look at setting things up I realized that if I hook up RO input to the saddle valve and the output to the float valve the barrel won't overflow but waste water will continue to flow out of the RO.

So the question is...how can I set the float valve up to shut off the water TO the RO unit so that the waste water will stop flowing when the water level in the barrel shuts off the valve?

Thanks
Lou

Lou, most RO/DI units will only dump waste water when the unit is use. When the float valve in the barrel shuts off the flow from the RO/DI unit, the waste water should stop too (usually within a minute or two). I'm not sure what RO/DI unit you have, though so yours may be different.

 

[Singlemalt]

Thanks John - I'll hook it up and see what happens. Oh it an Ebay special I got years ago for my 55.

 

[pitogo]

Your RO unit should have an ASOV-auto shut off valve most do. When you close the product line the pressure builds and will close off the supply to the membrane shutting the system down.

 

[vangvace]

Your RO unit should have an ASOV-auto shut off valve most do. When you close the product line the pressure builds and will close off the supply to the membrane shutting the system down.

Doesn't an ASOV require a pressurized water tank to turn off?


Lou, depending on the size of your reservoir. (barrel?) I would run two float valves. One near the top to turn off the water supply. The other one near the bottom to start the water running. This way you don't have your RO unit cycling on and off as often and more pure water in your tank.

 

[stcreef]

No, an ASOV does NOT require a tank. The pressure build up from the closed float valve is enough. It does however require descent pressure from the water source. 40 psi if I am not mistaken. Also the membrane will continue to make waste water as long as the water source is available. So if you use a float valve, you need an ASOV. Also make sure you have a check valve on the RO side of the membrane before the ASOV. I'll see if I can find you a diagram.


Here is a PDF with some different configurations:

http://www.spectrapure.com/manuals/LLC_MAN.pdf

 

[Singlemalt]

Went to dinner and came back to check if the valve shut off everything and it did. Valve up = no waste water flowing through the unit. Works like a charm.

Thanks to all who weighed in.

Lou

 

[DaveK]

Personally, I'd never want to completely trust a float valve.

If you can, install a bulkhead fitting higher than the float valve, and plumb it to a drain. That way if the float valve sticks in the open position, you don't end up with a flood.

 

[JohnS_323]

Personally, I'd never want to completely trust a float valve.

If you can, install a bulkhead fitting higher than the float valve, and plumb it to a drain. That way if the float valve sticks in the open position, you don't end up with a flood.

Thanks a good idea Dave. Also, something a friend of mine did was glue (or rubberband) a nice size piece of styrofoam to the top of the float arm. This way if it sticks for any reason the foam will help pull it up. It's certainly not a replacement for a bulk head to handle over flows but it is a cheap way to make sure the float floats.

 

[Singlemalt]

Thanks guys. The RO resivoir is in an unfinished part of the basement. I'm down there a lot an any floods roll toward the French Drain. Given that I think I'll go with the styrofoam method.