MES Dolly 225 Questions

[concord maple]

Just completed upgrading Dolly 100 to 225 and I am running only 150 psi compared to 210 psi when processing with the single membrane. I am leak testing and checking with distilled water on 2 brand new membranes. When I concentrated sap on the single membrane running the flow meters at 0.8 gpm concentrate I would be at 0.8 gpm permeate as well. This morning with the test I was running 0.8 gpm concentrate but permeate was running 3.5 gpm. Is this because I am not testing with sap?

[Super Sapper]

The distilled water will go through filter at a faster rate than sap will, so you will get higher permeate flows.

[concord maple]

Will the pressure increase when I start running sap back to when I was running the single membrane (210 psi)? I have never adjusted the recirc screw from day one. It is running at 150 psi with the second membrane installed compared to 210 with single post at 0.8gpm concentrate.

[maple flats]

I'm not familiar with that RO, but in general any RO gives greater permeate flow and lower volumn but higher sugar % for concentrate. With that in mind, it all depends on the pump and the pressure the components are designed to handle.
Testing with distilled water is never going to give you an idea of how the RO will work with sap, with distilled water, while you can find leaks, the RO has nothing to seperate, like sap does.

[concord maple]

Ok. Thanks for the answers to my questions. I guess I will just run preservative in and wait until next season.

[concord maple]

Still trying to understand the pressure. So when I start processing sap the pressure will go up when running the concentrate at 0.8 gpm compared to 150 psi with distilled water at 0.8 gpm?

[toquin]

Yes. When just running water there us nothing for pump and membranes to do. But add a little sugar (sap) to the mix and they have to start working,pressure goes up.You will wonder why you didnt get the RO sooner. We cut time boiling and wood use in half.

[concord maple]

I just added preservative into the system and I usually ran the needle valve at 3.5 gpm concentrate when I rinse and add preservative at end of season when it was 1 membrane. Now with the newly installed second membrane the RO was shutting down when I got to 2.0 gpm with the needle valve for the concentrate. Not understanding why this has changed. Any ideas or help?

[concord maple]

I should have clarified that when running at 2 gpm concentrate the permeate is at 2.25 gpm.

[toquin]

It has a low pressure shut off,I think its around 30 psi

[concord maple]

Yes I believe it is around 30 psi for low pressure shutoff. I am not understanding why parameters have changed going from one membrane to two. Running one membrane I could run my concentrate needle valve to 3.75 gpm before the low pressure switch would shut it off. Now with adding the second membrane, I can only run the concentrate needle valve to only 2.0 gpm until it shuts down.