Looking for help troubleshooting RODI pressure. (Before membrane)

[Valhalla Reefer]

Hi looking for some help with troubleshooting RODI pressure.

I’ve recently replaced all filter thinking this was the issue but I’m still getting close to 0 psi on gauge when making new water.

The pressure gauge (glycerin type from BRS) is installed between last carbon stage and the entry into RO membrane.

I’ve tested each pre filter by installing the gauge after each one..and getting a reading at close to house pressure of 55psi after each. But as soon as I place the gauge just before the membrane, it doesn’t read higher than 2psi.

It’s a brand new RO membrane (75gpd Dow Filmtec). The inline flush valve/pressure reducer is in correct position (perpendicular) and is for this membrane.

The unit is still producing 0 TDS water..but how am I supposed to know if pre-filters are becoming clogged if the gauge is already showing near 0 psi? (All while I’m getting house pressure readings of 55psi after installing gauge after each pre filter canister?

Lastly, if I place gauge before the auto-shutoff valve, install a closed valve on the end of the gauge and turn on water supply, I also get a 55psi reading.

I’m at a loss as to what’s going on. Am I missing something obvious?

Help or advice would be greatly appreciated.

 

[SteveMM62Reef]

Interesting- ok, perhaps the issue is with the gauge itself. Appreciated

Problem wasn’t with the Gauge, Port it was Attached to was Clogged.

 

[Valhalla Reefer]

Not sure where you have your gauge now but before the membrane is where you want it. Mine is screwed into the membrane housing and reads the same 80 psi running and shut off

How do you have it hooked up to the water supply? If you are using a pierce valve look there.

Thanks. I have pressure gauge now re-installed just before RO inlet.

My house pressure is 60psi and I’ve plumbed RODI unit off a a dedicated supply just off of 1” main’s PRV. (3/4” pex)
I could adjust the PRV for higher than 60psi if needed.

Yes it’s bizarre then how even with all new filters and membrane that I’m not seeing the same 60psi pressure at both locations.

Do you think not hearing a “hiss” sound from flow restrictor/flush valvecould be potential culprit? (its super quiet when running, can only hear with ear right up to it)

What’s also odd is how I’m still getting 0 tds before and after DI stage.

Appreciate your response.
I’ll now check gauge line for potential clog/debris as op mentioned.
Cheers

 

[Valhalla Reefer]

Problem wasn’t with the Gauge, Port it was Attached to was Clogged.

Thanks ok- yes that’s what I meant actually.

 

[Valhalla Reefer]

Thanks again.

I’m not sure if you read in earlier post that after I tested the pressure after each pre-filter port (and got same 60psi house supply pressure after each ) I then re-installed pressure gauge just before the RO inlet, and did a test by installing a ball valve just before RO inlet. (Placed at arrow location in below pic)

When that valve is closed, I get 60psi…and when it’s open and unit is making water, the gauge shows 0-5psi.

And 0 tds tested before and after DI.
I should mention I also have 3 way valve before DI that I use when flushing membrane.

I’m now wondering if the issue could be a faulty flow restrictor/flush valve then(?) I’ve removed and visually inspected. (When running, there’s no loud hiss sound )

Cheers

 

[Valhalla Reefer]

Thanks again.

I’m not sure if you read in earlier post that after I tested the pressure after each pre-filter port (and got same 60psi house supply pressure after each ) I then re-installed pressure gauge just before the RO inlet, and did a test by installing a ball valve just before RO inlet. (Placed at arrow location in below pic)

When that valve is closed, I get 60psi…and when it’s open and unit is making water, the gauge shows 0-5psi.

And 0 tds tested before and after DI.
I should mention I also have 3 way valve before DI that I use when flushing membrane.

I’m now wondering if the issue could be a faulty flow restrictor/flush valve then(?) I’ve removed and visually inspected. (When running, there’s no loud hiss sound )

Cheers

Btw I only mention the lack of loud hiss sound from flow restrictor because I definitely remember that sound being louder when making water on my older 50gpd setup.
Unless someone has something else to try or has advice on a better combo flow restrictor/flush valve- I’ll order a replacement one from BRS and see if that’s the fix.

 

[GoVols]

Interesting thanks. Much appreciated
I’ll save those in case needed.

I don’t think I’ll need a booster as my house pressure is 60psi and I’ve plumbed a dedicated supply just off of main’s PRV which I could actually dial higher psi if needed, maybe I should.

Cheers

Were you able to get your ro/di unit rolling?

If so, what was your issue?

Thanks

 

[Valhalla Reefer]

Were you able to get your ro/di unit rolling?

If so, what was your issue?

Thanks

Hey there,
Well it’s still making 0 tds water as it’s been from the beginning of troubleshooting ..however I never did figure out why my gauge reads so low when making water, despite all new filters and membrane.

Ill buy new flow restrictor/flush valve to see if that the culprit and provide update if that’s the fix.

 

[GoVols]

Hey there,
Well it’s still making 0 tds water as it’s been from the beginning of troubleshooting ..however I never did figure out why my gauge reads so low when making water, despite all new filters and membrane.

Ill buy new flow restrictor/flush valve to see if that the culprit and provide update if that’s the fix.

If you did not buy new di resin, then buy some and recharge it's canister. Then recheck your tds meter readings after the di stage. Make sure your tds meters probes are in the right position.

Start at 1:20

 

[Valhalla Reefer]

If you did not buy new di resin, then buy some and recharge it's canister. Then recheck your tds meter readings after the di stage. Make sure your tds meters probes are in the right position.

Start at 1:20

Thanks for your reply.
Yes it’s new DI resin, but I also have an 3-way valve installed before the DI stage that lets me bypass DI (for RO membrane flushes and for drinking water).

The TDS meter is also new, and I ensured the pins are correctly positioned . (It’s the first time using AutoAqua’s TDS meter..my previous HM meter finally quit and I thought I’d try this new style )

If you’re also using a pressure gauge (installed just before the RO housing inlet)…I’d be curious to know what your pressure reading is when making water.

Further details..
My water supply pressure is 60psi and to minimize pressure swings when others in the home are showering etc..I plumbed a dedicated 3/4 supply line to just before my RODI unit straight from the home’s 1” main (branched just after PRV..which I set to 60psi).
I can test that same 60psi after each pre-filter…but, when making water, tge pressure drops to 0 then slowly rises to 5psi.

I expect some drop, but is this normal for a 75gpd system with 60psi supply pressure and all brand new pre-filters, membrane?

Cheers

 

[GoVols]

I expect some drop, but is this normal for a 75gpd system with 60psi supply pressure and all brand new pre-filters, membrane?

Cheers

If your new valves do not change things for the long haul, you may need to go with a booster pump that produces a stronger back pressure.

Would not feel comfortable to raise your incoming plumbing before it ties into your ro/di lines to 80psi

Please watch the below video to the end.

 

[Fredinva]

Valhalla Reefer​

"I can test that same 60psi after each pre-filter…but, when making water, tge pressure drops to 0 then slowly rises to 5psi
I expect some drop, but is this normal for a 75gpd system with 60psi supply pressure and all brand new pre-filters, membrane?"

Please totally forget any previous pressure gauge readings while the pressure gauge was
anywhere except before your RO MEMBRANE. You have finally figured the gauge needs to go before the membrane. This is because the membrane requires the higher (50 to 90) psi to function properly. Remember your pushing water through a membrane with tiny tiny holes and this will ultimately reduce pressure down the line (after membrane).
if you still had 60 psi after di, you would be spraying water into rodi reservoir in lieu of it just dripping in like it does.
btw, you would still benefit by purchasing a 90 psi booster pump! your ro membrane would become more effecient!!