4x40 RO - What would you do different??

[craigwade2005]

As the title suggests I’m building a single post 4x40 RO with a 190 GPH procon and 3/4hp motor. This will be similar to the single post from the RO bucket. Here’s my plans -

190 GPH procon - sap tank above pump level.
3/4 hp Dayton Motor.
1/2” stainless fittings and Goodyear hose
Recirculation needle valve with 3/8 line.
3 flow meters 0.1-1 gpm


For people that have built similar, what are things you would change or adjust?
Does anyone have a good option for a low sap level shutdown? I know I can’t use a low pressure switch, maybe an optical sensor on the feed line or something similar?
I know many will say go bigger, however it is not an option for me at this time and the single post is more than enough for my 2x3 Mason.
Thanks!

[DRoseum]

GRL8-02 for level control. You just use wire probes to set the depth you want to shut off. I use these to control RO turning on/off automatically and as a safety shut off for my natural gas evaporator if the head tank gets too low. They are fantastic.

https://www.ebay.com/itm/392807118356?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=i8nwhndjqfw&sssrc=2349624&ssuid=GETUsOInQmO&var=&widget_ver=artemis&media=SMS

[craigwade2005]

D. Roseum, Thank you!
I found compatible sensors on eBay which look pretty simple.
Do you have a bulkhead style fitting probe or something similar to this? Thanks!
(Sorry photo upload is on the fritz )
https://www.ebay.com/itm/393674548588?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=uyegnppssry&sssrc=2349624&ssuid=DAfGzwgoS9e&var=&widget_ver=artemis&media=COPY

[DRoseum]

Anytime! Those sensors look nice. I actually just use 14 gauge solid copper wire (14/2). It uses resistivity of the fluid to sense the level so you just need 2 leads touching the fluid at the same time to trigger the relay. For the low level switch, I trim one of the wires to be slightly shorter than the other and then put it into the sap from the top of the tank all the way to the bottom...one lead can touch the tank bottom but the other needs to be slightly off the bottom to trip the low level switch when the sap runs below it. For high level switch just fix the wire leads to the height of the fluid you want to turn it on.

[BSHC]

I home built RO for this season. 4x40 single post.
www.kleen-ritecorp.com. 200 GPH Fluid-O-Tech pump + 3/4 HP Marathon motor
I am in Canada so I bought my water filter and RO housing plus membrane from https://www.maxwaterflow.com/
flow meters from amazon as well as a needle valve for recirculation line. The rest is just from the hardware store. I cant figure out how to link a photo but send me your email and i will send you an image. I used pex

[craigwade2005]

That sounds simple and I like it!
I found some cheap water tank sensors for a rv that I can install into the tank. Excited to try it!!

[minehart gap]

I'm missing something here. My first RO was a single post 4x40 and it had both high pressure and low pressure shutoff. I wouldn't run an RO without either of them. Too easy to burn up your pump or ruin you membrane. I am fairly sure that a little time looking through old posts on here would give you the how to.

[craigwade2005]

I'm missing something here. My first RO was a single post 4x40 and it had both high pressure and low pressure shutoff. I wouldn't run an RO without either of them. Too easy to burn up your pump or ruin you membrane. I am fairly sure that a little time looking through old posts on here would give you the how to.

Thanks for the reply. I probably could have worded it better and said that “I couldn’t run a low pressure shutoff after the feed pump since I’m not using one” I will have a low pressure / high pressure / high temp shutdowns. The low fluid level is just another level of safety as well.

[Hillcrest Maples]

What’s everyone doing for a recirc pump on home built 4x40’s? I’ve scoured all the “recirc” threads here but can’t seem to find a solid answer

[darkmachine]

I have a procon 330gph with two 4x40's and instead of a re-circulation pump, i just added a second needle valve for re-circulation. It seemed to work pretty well, and way cheaper than a second pump, not to say that a pump wouldn't do a better job, especially to keep the membranes clean. If you find a pump that someone is using let me know!