Not getting any flow out of permeate line

[Northbound1]

Got up to the shack last night and started the ro (ro bucket 20). When I woke up this morning the ro was still running for some reason the pressure switch didn't shut it down. Guessing it was running dry for 2 hours. Now I can't get any flow out of permeate line even with needle valve closed on concentrate line. Any ideas? I don't have the time or wood to boil straight sap

[wmick]

Are you still generating good PSI?

[maple flats]

Ask the RO Bucket guys (manufacturers) they can likely help.
It might just need a cold permeate rinse, maybe more.

[eustis22]

Heyyy...me neither! A little background: I built Hodorskib's 4 X 150 GPD RO system a couple three years ago but found it a little slow to handle my sap volume. My Shaque is not heated so freezing temps are an issue in ROing. So this year I decided to increase my thruput with a 2 X 400 GPD system so I upgraded my pump from the 8852 to the 5800 and scored a couple of membranes from a buddy who works in the water industry. I did the rinse/wash/rinse process yesterday and noticed nothing amiss. Of course, my needle valve was wide open so almost everything was flowing thru the concentrate line.

Anyway, yesterday I hooked up the system to my sap tank, turned it on, and...well, I was not whelmed. The needle was only just cracked (wanted to build up pressure) so there was a small dribble coming out the concentrate line but the bad part was that nothing was coming out the permeate line. The pump kept shutting down too. Turns out this pump's shutoff is at 60 PSI (and I was used to the 100-125 PSI of the 8852) so that explains that, I guess. The lack of permeate is mystifying. I know the lines are all hooked up to their proper outlets.....I saw the Perm line draining during the cleaning so there's no blockage.

I will test using a couple buckets of permeate with the needle closed and see what happens but any suggestions would be appreciated.

http://mapletrader.com/community/attachment.php?attachmentid=22185&stc=1

[wmick]

I am not very knowledgeable with membranes... But is it possible that your membranes simply need more than 60psi to permeate?

[eustis22]

You know, I didn't even think of that! I think my 8852 can generate more PSI. Maybe I will swap them out.

[eustis22]

Can you even RO in 70 degrees?