Why has flow slowed on my RODI system?

[Dom]

So I noticed that the flow from my RODI system has slowed considerably.

I used to generate 40 gallons of usable water in 24 hours. Now production is approximately 1/2 that amount.

I've replaced all 5 stages in the system, but still no improvement.

Has this ever happened to you? Did you resolve the problem? If so, how?

Thank you,
Dom

 

[The_Paradox]

What’s your pressure and waste:RODI ratio?

 

[Lavey29]

Do you have a back flow valve to purge and flush the system?

 

[Kmst80]

So I noticed that the flow from my RODI system has slowed considerably.

I used to generate 40 gallons of usable water in 24 hours. Now production is approximately 1/2 that amount.

I've replaced all 5 stages in the system, but still no improvement.

Has this ever happened to you? Did you resolve the problem? If so, how?

Thank you,
Dom

Could be a few things.
Number one is Temperature. In winter it takes longer than in summer to get the same amount of RO.
Number two is your sediment filter, obviously it filters out the big particles and therefore eventually will get clogged.
EDIT...just saw you changed all stages, could it be you changed your sediment filter with a finer new sediment filter?...they come in different microns.

 

[Dom]

What’s your pressure and waste:RODI ratio?

I don't know the pressure. It is water coming from the city system. That may have changed, but I'd have to reach out to the DEP and ask them if they've reduced pressure.

Typically, I generate 1-1.5 gallons of RODI from every 5 gallons that passes through the system.

 

[Dom]

Do you have a back flow valve to purge and flush the system?

Yes.

And I also have a device which is supposed to shut things down once the float valve moves into a closed position.

I wondered if one or both of these devices failed in a way to cause this issue.

 

[Lemons]

Stupid question, but have you changed your membrane recently?

If not then that'd be your issue.

But if you have then it is likely insufficent city water pressure to keep up with your demand i suggest a boster pump and a premembrane pressure gauge

 

[Dom]

Could be a few things.
Number one is Temperature. In winter it takes longer than in summer to get the same amount of RO.
Number two is your sediment filter, obviously it filters out the big particles and therefore eventually will get clogged.

Interesting; I never stopped to consider temperature, and after thinking about it, I can see how it would impact production. But the RODI system is in a climate controlled room at 72 degrees.

I thought the problem might be clogged filters, so, I replaced EVERYTHING, including the membrane.

But I am beginning to think this may be related to a clog somewhere. I may pull the float at the reservoir out and check for blockages and then work my way back to the source water.

 

[Cthulukelele]

Counter-intuitively, when the water pressure regulator in my house started to fail and my water pressure shot up to 110 psi I got a much worse daily yield of RODI water through the system. That may be worth looking into. Water pressure gages are cheap and you just hook it onto your main back of house water tap to measure. Anything over 80 psi can start interfering with the proper function of certain water-relevant things like water heaters, ice makers, and RODI filters.

 

[Dom]

Stupid question, but have you changed your membrane recently?

If not then that'd be your issue.

But if you have then it is likely insufficent city water pressure to keep up with your demand i suggest a boster pump and a premembrane pressure gauge

Yes, I replace ALL media when I first noticed this; membrane, resin, carbon...

I am wondering if the city dropped pressure. I understand that they plan on opening up the street to install a new storm sewer, so they may have reduced pressure related to that (although I don't see how they are related).

 

[PotatoPig]

Did the flow slow in late fall/early winter?

When the water/system is colder the flow rate slows down.

 

[Dom]

Counter-intuitively, when the water pressure regulator in my house started to fail and my water pressure shot up to 110 psi I got a much worse daily yield of RODI water through the system. That may be worth looking into. Water pressure gages are cheap and you just hook it onto your main back of house water tap to measure. Anything over 80 psi can start interfering with the proper function of certain water-relevant things like water heaters, ice makers, and RODI filters.

Interesting...

We do pay for our water here in the form of a quarterly bill. I know there is a meter on the main, but honestly, I never took a close look at it. I assumed it was just a total use meter and nothing else.

 

[Dom]

Did the flow slow in late fall/early winter?

When the water/system is colder the flow rate slows down.

Yes... I just learned that from an earlier post.

This theory has merit in my mind, so I will note how much production now and again over the summer.

 

[Lavey29]

Yes.

And I also have a device which is supposed to shut things down once the float valve moves into a closed position.

I wondered if one or both of these devices failed in a way to cause this issue.

It may be partially closed or clogged

 

[Dom]

It may be partially closed or clogged

I'm thinking one possibility is that the flush valve may "look" like it is functioning, but instead, the internal valve may be in a partial open position.

I'm going to remove it from the system as a test.

 

[Lavey29]

I'm thinking one possibility is that the flush valve may "look" like it is functioning, but instead, the internal valve may be in a partial open position.

I'm going to remove it from the system as a test.

Or hard water deposits have built up in the intake lines

 

[Kmst80]

Interesting; I never stopped to consider temperature, and after thinking about it, I can see how it would impact production. But the RODI system is in a climate controlled room at 72 degrees.

I thought the problem might be clogged filters, so, I replaced EVERYTHING, including the membrane.

But I am beginning to think this may be related to a clog somewhere. I may pull the float at the reservoir out and check for blockages and then work my way back to the source water.

Still the water in your pipes will be colder in winter. In summer it takes my system 3 hours to do 35 litres and in winter it can go up to nearly 4 hours.

 

[MnFish1]

So I noticed that the flow from my RODI system has slowed considerably.

I used to generate 40 gallons of usable water in 24 hours. Now production is approximately 1/2 that amount.

I've replaced all 5 stages in the system, but still no improvement.

Has this ever happened to you? Did you resolve the problem? If so, how?

Thank you,
Dom

We had some plumbing work - resulting in low pressure - do you have a monitor/pressure test? Since you've replaced all the filtration, etc - there could I suppose be a blockage in one of the pieces of tubing? PS when I read this there were no posts I could see - so sorry if I repeated someone else's comments

 

[The_Paradox]

Still the water in your pipes will be colder in winter. In summer it takes my system 3 hours to do 35 litres and in winter it can go up to nearly 4 hours.

In his case it’s double and suddenly. That’s a pressure issue the question is it the valve, line pressure, media induced back pressure.