RO/DI output pressure???

Hopefully someone can help shed a little light on the situation here.

I'm running a RO/DI straight to a float valve in my sump for top off. The problem I'm having is the RO/DI doesn't seem to be putting out enough pressure to keep the tank topped off.

The thing that's really wierd is my old cheaper GE RO unit from Home Depot worked this top off fine. The only difference between the two units is the older GE had an expansion tank and the new Air Water Ice RO/DI does not have an expansion tank. Would the pressure being built up in this expansion tank be what was topping off the tank with the old unit? I'm thinking the pressure that built up in the expansion tank was enough to push the water through the top off line and with the new RO/DI it's just a straight output that really can't build up pressure. Or at least enough pressure to stay running correctly.

Oh, the automatic shut off valve on the new unit isn't shutting off either but AWI said they would mail me out a new one today. Don't think that would be the cause of the low output pressure though.

Let me know what you all think. What am I missing? Is my thinking correct with the expansion tank and the output pressure that builds up?

 

Well I didn't get any response on this so I'm going to go ahead and order the expansion tank in hopes it will fix the problem.

 

That expansion tank won't fix the problem you don't have enough volume and that tank will give you about 3 gallons of pressurized water P/M me or E/M me if you want to discuss it , I log in for my P/m

 

Is there a pressure guage on this unit?

What is the PSI?

 

No pressure guage Matt but unit makes water at the rate it "should" without the top off line hooked up. I just don't understand how a crappy GE RO unit from Home Depot would run this auto top off fine for well over a year and then I upgrade to a better unit with more output and it won't run it. It's very close to keeping up with the tank but after 2 or 3 days the sump will get low enough that the return pump starts trying to pull air.

Do you guys have any idea if the Auto shut off valve not working on the RO unit would cause this? Maybe the RO is dumping too much water out of the drain to build up output pressure????

I'm stumped.


Roger email is on the way.

 

Not sure. But recently, many were discussing an ro/di auto top off:
http://www.3reef.com/forums/i-made/topoff-direct-ro-49461.html

I think dngspot would know as he did the same thing. I'd PM him as well.

 

Thanks Matt, I'll read through that this afternoon. I was really wanting to stay away from anything "powered" to do this becasue the old Kent float valve has worked awesome for well over a year.

I spoke with Roger and he thinks I've got an obstruction somewhere in the line. It's very possible since I took all of this stuff apart when tearing down the tank. I noticed the teflon tape on the threads of the float valve was everywhere when I took it apart. Wouldn't surprise me if I got some in the float valve in the whole process...