RO Auto-shutoff Valve with Widest Range

[l4tl]

Does anyone know of an automatic shutoff valve (ASV) for RO with a wide separation between ON and OFF pressures?

The widest-range valve I find is the Hydronamic ASV-ERP, which closes at 90% of line pressure (and opens at 70%, anecdotally, because no specs).

The 90% is ok, but I'm looking for one that opens at somewhere around 40%. Does such a thing exist? (I've searched, unsuccessfully.)

There are many threads like this, for example (my situation also), where an RO system was installed and, after a time, the homeowner notices rising TDS levels that are traced to infrequent, small discharges. @ditttohead's post here explains it well, along with how the ASV addition yields some relief.

In making corrections, I want them to be optimal (reason I'm asking about the best (widest-range) ASV for this application).



(This was to be my first post, until an unexpected detour. Godspeed Terry Love.)

 

[Fitter30]

Don't know about ro systems but a permeate pump is used to enhance the performance of the ro membrane and increases pressure and volume of water in the storage tank. Without the pump more wastewater goes down the drain. With a big differential won't it go lower that the storage tank pressure and increase wastewater defeating the purpose.

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[Sponsor]

 

[l4tl]

Don't know about ro systems but a permeate pump is used to enhance the performance of the ro membrane...

Apologies for not stating clearly, this is for a PP-equipped system. That detail was mentioned in the two OP links, which I thought was sufficient. (A post that gets it said with fewer words is always better. ... Unless entertaining haha.)

To optimally minimize tank-side dissolved solids due to TDS creep, the valve would close high and not reopen until the tank were at the minimum operational pressure, call it 20 psi in my case. Nothing on the market (I find) comes close to this.

The advantage to a pressure-actuated valve is; no electrics needed. Then manually flushing the higher-TDS permeate (only a cup or two) before the next ON cycle each time -- very easy and doable in my case -- would essentially eliminate the problem.

So I'm still hoping someone knows of a wide-range shutoff valve. If not, there'll be no choice but to go electric.

 

[Fitter30]

Contact https://terrylove.com/forums/index.php?members/ditttohead.49098/
He's a water expert.

 

[Reach4]

Apologies for not stating clearly, this is for a PP-equipped system. That detail was mentioned in the two OP links, which I thought was sufficient. (A post that gets it said with fewer words is always better. ... Unless entertaining haha.)

I think this disproves that theory.

What is a PP? Polypropylene? I think you mean permeate pump, and throwing in your cool abbreviations does not help clarity.

Expecting people to follow two links doesn't aid communications either.

 

[l4tl]

Contact https://terrylove.com/forums/index.php?members/ditttohead.49098/
He's a water expert.

Tagged him in the OP, hoping he'd get the notification and pay a visit here. May have to PM and ask directly, thanks.

 

[l4tl]

I think this disproves that theory.

What is a PP? Polypropylene? I think you mean permeate pump, and throwing in your cool abbreviations does not help clarity.

Expecting people to follow two links doesn't aid communications either.

Whoa, a cheery good morning and welcome to you.

This board contains a wealth of information, the linking to previous posts of which is a well-accepted way to set the context of a stated question.

Accusations of "throwing cool abbreviations" are unhelpful, at minimum, and invalid when the definitions of those acronyms (in this case) are part of the OP, whether by link or plainly stated. Such negative posts cast this forum in a bad light; you may wish to rethink and reword to something positive. Deletion is an option.

If unwilling to take the time to read and understand the question, please move along and let others help. That's actually a good general policy for all of us to follow.

 

[Aaroninnh]

Apologies for not stating clearly, this is for a PP-equipped system. That detail was mentioned in the two OP links, which I thought was sufficient. (A post that gets it said with fewer words is always better. ... Unless entertaining haha.)

To optimally minimize tank-side dissolved solids due to TDS creep, the valve would close high and not reopen until the tank were at the minimum operational pressure, call it 20 psi in my case. Nothing on the market (I find) comes close to this.

The advantage to a pressure-actuated valve is; no electrics needed. Then manually flushing the higher-TDS permeate (only a cup or two) before the next ON cycle each time -- very easy and doable in my case -- would essentially eliminate the problem.

So I'm still hoping someone knows of a wide-range shutoff valve. If not, there'll be no choice but to go electric.

I've got a permeate pump and am using the pentek pentair 1:1 membrane and my rejection rate is amazing. I just tested it a couple weeks ago...I do it every january. My raw water has a TDS of 65, after the system its 2. This is with a membrane that has passed 2 years of service.

Lowering the cut-in will also leave you with less water in the tank. For me, since I have to cook with it as I have arsenic, I may need to pull a gallon to make a big pot of Pasta. I want my tank to fill as quick as possible.

The permeate pump is the best way to improve the rejection rate by reducing backpressure on the membrane. You already have that. Anything more seems like over optimization to me.