Gravity fed auto top off - need critique

[P.Sherman]

For those familiar with the nurce and similar gravity fed top off units, can you tell me if this will work? I have a picture attached. What I don't like about gravity fed top offs is the process of temporarily taking it apart to refill it with FW.

Basically, when the topoff unit runs low on FW I would like my RO/DI unit to fill it up either by float valves or manually opening a gate valve. The opening for the RO will be through a check valve to prevent air from escaping out.

What I'm worried about is when the RO water is coming in something else has to come out. Will air escape out the air line (which I'm hoping for) or will it cause more water to exit out to the sump? Or is this a waste of my diy time?

[jonathon_otts]

While filling the 5 gal jug with RO water, the escaping air will take the path of least resistance. This should be through the air line.

[TroyPierce]

Originally posted by P.Sherman
Basically, when the topoff unit runs low on FW I would like my RO/DI unit to fill it up either by float valves or manually opening a gate valve. The opening for the RO will be through a check valve to prevent air from escaping out.

I'm confused PS. You're looking for an automatic top-off for your gravity fed automatic top-off? If you're gonna put in a float valve, check valve, etc. from your RO/DI unit, why not bypass the whole GF top-off part and have the RO/DI go directly to the sump?

Guess I'm missing sumpin' here.

Troy

[T Sandman]

I think the idea here is that this person did'nt want the r/o to be cycling repeatedly. And in the event that the sump level is fluctuating it would be difficult to use a float switch for top-offs.

I agree with jonathan, you would need to vent air when filling up your 5 gallon container or you may have a problem.

[P.Sherman]

You're right in that I don't want my RO unit turning off and on at the slightest drop in the sump. With this setup I can wait until the water level is very low before activating the RO unit.

I figure that the air intake line will be just below the surface of the water. As water enters from the RO the pressure has to be released, which I think, should be the air exiting out since that would be the weakest point. It's kinda like a surge device. When a surge tank fills up the air is forced out which eventually starts the siphon.

[thedogofwar]

I'm sure most any 5G container should be strong enough, but I just wanted to point out that I attempted a gravity topoff with a milk jug, the thing just collapsed under the pressure.

[P.Sherman]

I've been searching the forum and have decided to go with a peristaltic pump instead. It's a constant drip method that I can also dose with kalk.

[TroyPierce]

Originally posted by T Sandman
I think the idea here is that this person did'nt want the r/o to be cycling repeatedly.

Okay, that makes sense. Sorry.

[capricorn]

How is this project going with the peristaltic pump? Just curious since I want to be able to do same.

[P.Sherman]

The peristaltic pump works great! I have a 5 gallon water bottle that I pump from and I don't have to worry about it for another 4 days. You have to dial it in at first to get it balanced because it will obviously evaporate faster during the day than at night. Also, as a safety precaution you'll want to fasten the tube coming from water bottle to the pump, a simple piece of tape will do, so if the rubber piece of the tube wears out and breaks (supposedly after 3 months) the tube will not fall to the ground and syphon out your water bottle.