Home built RO pump question

[paulslund]

Thank you. Yes you are correct in your understanding. It works at 50/50, just more membrane fouling which can reduce effectiveness/life of membrane over time.

Aliexpress is legit. I've bought thru there a few times.

Ok thanks! I was starting to get confused (which isn't that hard )

[82cabby]

Were you looking at procon pumps or aquatec pumps? Many use aquatec 8852 for 1 or 2 of the 400 gpd membranes. I did this for a few years.. However a better option is the Coronwater TYP-8900 pump. Much higher flow rates at higher pressures. Can actually go up to 5 of the 400 gpd membranes in series with that pump. I have built 2 units like that - use both in parallel for big runs or one at a time on slower days. Both aquatec and coronwater are diaphragm pumps and can self prime and run dry. Good for smaller operations. Much like what the RO bucket uses in its RB5 - rB25 models.

The one you linked to would not work. The flowrate is probably open flow at 0 pressure. There is a reason its so cheap.

Procon pumps are rotary vane pumps.

Sorry to jump in but what power supply do you use with the Coronwater 8900 and do you have a source for replacement diaphragms? I am going to order one but would like to get all the items and a backup diaphragm all at once.

[Swingpure]

Sorry to jump in but what power supply do you use with the Coronwater 8900 and do you have a source for replacement diaphragms? I am going to order one but would like to get all the items and a backup diaphragm all at once.

Not Dan here, but when you scroll down on this link, you can see the power supply and diaphragm options that go with it.
https://www.aliexpress.com/item/1005...d=TlS4rCQZrXF7

[82cabby]

Not Dan here, but when you scroll down on this link, you can see the power supply and diaphragm options that go with it.
https://www.aliexpress.com/item/1005...d=TlS4rCQZrXF7

I’m sorry, I really don’t know why I’m having such trouble with this. There are several power supplies, I’m guessing I need the 5amp one based on the current draw listed for the pump. The only diaphragms showing up for me are for chainsaw carburetors!

[DRoseum]

I actually used 24 vdc power supplies similar to this one: https://a.co/d/dmfxpTl ... because I had them available and because I built other automated controls into my RO such as tank level sensors that can automatically turn my unit on or off and a heater to keep it from freezing. I put it all in a weatherproof workbox and vented the bottom with some holes for heat dissipation.

HIGLY recommend more than 5 amp rating. Look for 10 amp. The 5 amps is at 80 psi. Operating at 120 you will see higher current.

As for spare diaphram- not sure. I bought 2 pumps with one originally in mind as a spare before I built a 2nd unit to increase processing speed on heavy flow days. Will have to research diaphram availability further.

[82cabby]

So, once again sorry for hijacking, but this way all the info is in the same thread.

D.Roseum, I have looked at this pump that you use in your setup and I know you have had good luck with them. (link) https://www.aliexpress.com/item/1005...d=TlS4rCQZrXF7

I spoke with an aquatec dealer and they recommended this pump when I described the application: http://www.aquatec.com/documents/dow...6.00%20LPM.pdf


I have had such good luck with my aquatec 8852 and the parts are available, I don't mind spending the extra money on it if it will serve the purpose. In looking at the specs, it seems like it will work, but I am far from an expert on these things. Will the aquatec 5357-2LM2-B738 work for four 400GPD membranes in series with a recirc line?

Thanks!
Cabby

[carls47807]

That is a really good pump and the flows are similar to the coronwater one. It looks like the duty cycle would be around 2 hours if you ran it around 100-110psi, and then you would get close to tripping the thermal shut off. The pumps we use have a continuous duty cycle at bypass pressure (150psi). Depending on how you plan to run it, it could work for you. Aquatec makes a good pump but the larger ones tend to run hot for some reason (and their thermal cutoffs are a bit conservative i.e. less than the <145F they state).

[DRoseum]

I have spent a lot of time looking at that pump. I believe it's a quality product and flow/pressure specs look great and should work for that setup.

My only concern with this pump is the thermal shutoff. You might not be able to run continuously for greater than 1 hour at higher pressures/amps. See heat rise graph on page 2 of spec sheet.

Also, 2+ years ago when I built my RO this pump could not be found via any aquatec distributors. I also talked with aqautec but they won't sell direct and referred me to suppliers who none of which carried the pump. It was brand new at that point.

[eustis22]

Anyone use a ShurFlo 4008 to move sap thru 400 GPD membranes?

[DRoseum]

Those won't go high enough on pressure.