RO/DI waste line assistance needed

[eliashickman]

I just bought a new system. Here in Korea we don't have the fancy kind of systems that are available in the good ol' US of A. :(

Anyway, my system is connected and up and running. But it's running very slow. Also for the waste line from my membrane I don't have a flow restrictor, instead I'm using a shut-off valve. In my old system, I didn't even have a waste line. :twitch:
Since my RO/DI system is connected directly to the water line, the waste line is always going to be running. Does this sound typical? I have restricted the amount of water coming out however I'm not sure how much I need to restrict.

The other thing is that I don't understand why the water is moving so slowly.

Thanks :)

[lordofthereef]

The waste line should not always be running. I am no expert with RODI but I do know that my waste line only runs when I am "making" RODI water. My unit was plug and play though so it didn't take much effort at all to set up. Hopefully someone will chime in, but in the mean time I would shut your water off. You are going to be wasting a TON if your waste is constantly running.

[Playa-1]

The output is determined by how efficient the filter is. Some of the fancy systems here in the good ol" US of A can produce 1 gallon of RO/DI water for every two gallons of waste water. But most systems are not that efficient. A more common range is between 4:1 and 10:1. So it's normal for the waste water to have a higher flow rate then the product line.
On a simple filter you will have to turn on the water to make the filtered water and then turn it off when you are finished. If you don't turn it off then the water keeps running thru the waste water line and depending on how the filter is set-up could cause some serious problems. Many of the fancy systems have an auto-shutoff valve so that once the RO/DI reservoir is full, The water stops flowing thru the waste water line. This is usually set-up with a reservoir and a float valve along with the auto-shutoff valve.
As far as the water moving slowly goes. It's normal for the water to move thru the filter somewhat slowly, especially the product line. You can put a container on the end of the product line and the end of the waste water line to see what you ratio is from the waste water to product water. That would be a good place to start. Also test the water to make sure the filter is working properly. It would be a good idea to know what the water pressure is to the filter as improper water pressure can affect the performance of the filter. I don't use a restrictive device on my waste water line, but I've heard of others doing it.

[eliashickman]

I mostly figured it out guys. I have to buy a pump, a switch that will detect the water pressure and start and stop it automatically, and a flow restrictor for the waste line. The only thing I now have a question about is whether or not I should connect the switch to my sump. I've had my auto top off plumbed directly to the sump and I know it's a bad idea but I've never had a problem.

So my setup would look something like this


| |
| Main |------Sedement ----- Precarbon ----Membrane----Postcarbon
| | \ / \
\ / DI
\ / |
Motor ---------------------switch
|
Sump


I just wonder if such low pressure from the float valve would cause damage to the motor.