Float Valve?
 

Where can i get a float valve for an auto top off system?

I can't seem to find one.

Thank you

Home Depot sells float valves. All plastic ones made by "Wait" or something like that. Its for humidifiers.

http://www.jlaquatics.com/phpstore/s...ID=ro-kpfvalve

Are you trying to control and RODI until, or just water from a reservoire into your sump?

Here's my HomeDepot (might be Waite) humidifier valve hooked directly to the ro/di. Doubt the sump level varies 1/4" in total since installed (salt line you see is since from adding some extra fans).
http://i67.photobucket.com/albums/h316/das75/float.jpg

Humidifier valve connected to an RODI, can you explain this more?

How do you stop waste water production from the RODI?

Have the Aqua-safe with tank, float valve is hooked up to the ro/di output line. RO/DI unit works as normal, no demand (no flow), no waste water.

Grand plan was to have the ro/di unit feed a reservoir with aeration (for pH adjust and to limit possible amount of fresh water that might be added if float failed), reservoir supplying sump via float valve.

Thinking now this setup works great, don't need to worry about topping up a reservoir, only adding little ro/di water a time so doubt I'll get much pH swing (system volume ~200g) and really, how many people have ever flooded their basement because their humidifier float valve got stuck open?

But waste water production doesn't stop unless you stop the water supply to the RODI, how does your system control this?

Check if your unit is continually making waste water or not, even when the tank is not demanding water.

The RODI will stop waste water production if you have a hydraulic valve plumbed into the RODI that detects the pressure increase when the float valve closes, do you have this then?

I picked up an auto shut off float valve at Wai's. It was worth the $20.

My Aquasafe RO/DI has an auto shut off valve to stop the water flow.

As a side note, if you run your RODI production water line a long distance, those waste water shut off valves don't work so well, they need pressure bladders installed.

I had mine setup this way, it failed to often for me. But I run my output line across my house.

Mark, does your aquasafe have a built in pressure activated valve to shut off waste water production then?

The Aqua-safe units have the valve and just assumed all other units would have one included as well (why I was specific).

As the valve is mounted on the ro/di unit sensing the pressure differance between unit supply and output, can't see why distance would matter (my float is on the end of a probably 20' run).

No, they don't all come with them, I didn't know any of the did come with them.

The RO unit I have came with an electric pump so it can go the distance and has a built in auto shutoff in the unit

?? The feed line can go a long distance, but when the float valve closes, the pressure buildup over the length of the line is not enough to trigger the hydraulic shut off valve. Installing a pressure valve boosts the pressure in the line.

Where does your electric pump come into play in your setup exactly? Are you sure it doesn't boost the psi of your house water pressure for the RODI?

I thing Greg is talking about a booster pump with a pressure switch.

That's it Harvey. I thought that was what we were talking about. Didn't mean to create a thread hijack.
I have my RO running to a res. and from there I have an "Aqua Medic" auto top off unit. I only set it up very recently but so far it works really well.

Thats ok. Your pump is for input pressure, I meant pressure created on the output by a float valve closing. No pump can do that, but pressure bladders like spectra pure sells with their units will.