RODI producing very little product water

[dnott3]

I have a brs 75 gpd unit that I replaced the membrane with 100 gpd membrane and it isn't producing much product water. I changed the flow restrictor to 800 ml/min. I have 56 psi going into the membrane. All of the filters are new. I removed the shut off solenoid since I don't use it. Anybody have any ideas as to why it's only producing drips? It was producing faster with the 75 gpd membrane.

 

[ReefStable]

The only things that come to mind from when I did this are:
- Is the flow restrictor on correct or is it backwards. It's easy to mix up.
- Does the restrictor have a flush valve and is it closed?

If it isn't either of these, I would likely undo and redo all filters and the membrane. Something may not be seated correctly.

Hope this gives some ideas.

 

[dnott3]

The only things that come to mind from when I did this are:
- Is the flow restrictor on correct or is it backwards. It's easy to mix up.
- Does the restrictor have a flush valve and is it closed?

If it isn't either of these, I would likely undo and redo all filters and the membrane. Something may not be seated correctly.

Hope this gives some ideas.

Flow restrictor is installed correctly and it does have a flush valve that is all the way closed. Could the new restictor I got be a bad unit? It's pretty noisy compared to the 500.

 

[ReefStable]

Flow restrictor is installed correctly and it does have a flush valve that is all the way closed. Could the new restictor I got be a bad unit? It's pretty noisy compared to the 500.

Definitely should not be making noise. Try opening the flush and see if anything changes. Otherwise it may be a bad restrictor.

 

[dnott3]

Definitely should not be making noise. Try opening the flush and see if anything changes. Otherwise it may be a bad restrictor.

When I opened the flush valve it stopped making noise and seemed to be working like it shouldve

 

[dnott3]

Definitely should not be making noise. Try opening the flush and see if anything changes. Otherwise it may be a bad restrictor.

Had a new restrictor sent to me and installed it. It is a 800 restrictor. It's still only producing drips of water. I just had it running for 2 hours and it only made about a cup of water. Any ideas?

 

[EeyoreIsMySpiritAnimal]

Had a new restrictor sent to me and installed it. It is a 800 restrictor. It's still only producing drips of water. I just had it running for 2 hours and it only made about a cup of water. Any ideas?

Can you post a picture of the flow restrictor in the closed position? Sounds a lot like you've got it open...

 

[EeyoreIsMySpiritAnimal]

Also, did you remove and reset the membrane, and are you sure it's not in backwards?

 

[dnott3]

Can you post a picture of the flow restrictor in the closed position? Sounds a lot like you've got it open...

Also, did you remove and reset the membrane, and are you sure it's not in backwards?

Membrane has been pulled out and reset a couple times.

 

[ReefStable]

Can you post a picture of the flow restrictor in the closed position? Sounds a lot like you've got it open...

I was going to ask the same thing.

@dnott3 Can you post a photo of it in the not-working, closed position?

 

[dnott3]

I was going to ask the same thing.

@dnott3 Can you post a photo of it in the not-working, closed position?

I think I'm confused by what you mean. Do you want a picture with the flush valve in the open position?

 

[Brett7397]

Just for troubleshooting purpose put the 500 back in. If flow increases you will know where the problem is.

 

[dnott3]

Just for troubleshooting purpose put the 500 back in. If flow increases you will know where the problem is.

I can try when I get home but wouldn't it just affect the amount of waste water? If I understand it correctly

 

[Brett7397]

Yes it will not be as efficient but it will tell you if it's the 800 restrictor or the
RO membrane.

 

[Malum Argenteum]

I run a 550ml restrictor (BRS, barrel type) on my 100gpd membrane. The 800ml did not allow high enough pressure for good production on my system. The 550ml has been working well (2 years since I installed it).

 

[Brett7397]

I run a 550 on mine. I have a 100gpd with a 150gpd piggyback to save water. When I had my 75gpd I ran an 800.

 

[dnott3]

Just for troubleshooting purpose put the 500 back in. If flow increases you will know where the problem is.

I ran it for 2 hours again with the 550. It did produce more water but not a significant amount, maybe 2 cups. But still significantly a lot less than when I was running the 75gpd membrane. Unfortunately I already threw out the old membrane or I would put it back in and see if it made a difference. I'm leaning towards just buying a new membrane and see if it makes a difference.

 

[Brett7397]

That should get you making water again.

 

[Malum Argenteum]

I ran it for 2 hours again with the 550. It did produce more water but not a significant amount, maybe 2 cups. But still significantly a lot less than when I was running the 75gpd membrane. Unfortunately I already threw out the old membrane or I would put it back in and see if it made a difference. I'm leaning towards just buying a new membrane and see if it makes a difference.

Another thing to maybe try before that is to change the prefilters (after 6 months of use, they're due for a replacement anyway, in my opinion). Not sure that will help, but needs to be done anyway and might just be the thing.

 

[dnott3]

Another thing to maybe try before that is to change the prefilters (after 6 months of use, they're due for a replacement anyway, in my opinion). Not sure that will help, but needs to be done anyway and might just be the thing.

All of the prefilters are brand new and were put in when the new membrane was.