RODI - New Carbon and Sediment Filters - Low Membrane Pressure

[Quietman]

Odd issue here I can't figure out, I'm sure it's something simple but before I tear down want feedback if someone has seen this before to save me some time and money.

Input line pressure 80# (I have a gauge on input)
Input pressure to membrane 25#

Last week - Replaced carbon and sediment blocks with new last week and just now checked again (2x now) so make they're not in wrong (be very hard to do but...just in case). Added an input pressure gauge and local supply valve. No other changes beyond that. Tap is off the cold water side (hard connection so really can't mess it up).

Setup - Running Koolermax 122 for Carbon/Sediment and RO Membrane (with BRS 3 stage DI). No booster pump (don't need it with my city pressure of 80#), replaced stock flow restrictor with a rated flush valve/flow restrictor (800ml) for 100gpd system when installed 2+ years ago. Again, made about 100 gpd before this last sediment/carbon block change.

Output is about half based on how long to fill my tank (before was about 2 hours to fill 10 gal, now it's 4 hours) so the pressure gauge is reading ok as the output is what I'd expect for that pressure. 0 TDS output from DI still and really TDS out from RO is same (just takes a few min longer to get there when starting).

Ran this system for a couple years, replaced carbon and sediment twice before - no issues.

Any thoughts before I start replacing flow restrictor and auto shut off blocks?

 

[Reef.]

I would try removing the input valve gauge, see if that is slowing the flow.

 

[Quietman]

Pressure reads 80# after the valve, but just switched it out since that's easy...no change.

 

[Reef.]

Pressure reads 80# after the valve, but just switched it out since that's easy...no change.

my next suggestion was going to be removing the filters one at a time and seeing if that increases the flow, you would have to decide if the risk to the membrane is worth taking with no sediment filter in place, you could remove the di resin for this.

 

[JoshH]

Pressure reads 80# after the valve, but just switched it out since that's easy...no change.

Do you have a spare valve kicking around?

 

[Quietman]

my next suggestion was going to be removing the filters one at a time and seeing if that increases the flow, you would have to decide if the risk to the membrane is worth taking with no sediment filter in place, you could remove the di resin for this

Took all blocks out....same reading.

So...when I open bypass pressure drops to zero, with it shut it's at 25#.

Should I replace restrictor/bypass or check the pressure gauge is working (no real reason to doubt as it responds and was reading 80# before replaced the blocks.

Puzzling...

 

[Reef.]

Took all blocks out....same reading.

So...when I open bypass pressure drops to zero, with it shut it's at 25#.

Should I replace restrictor/bypass or check the pressure gauge is working (no real reason to doubt as it responds and was reading 80# before replaced the blocks.

Puzzling...

the dropping to zero when open is correct, doesn’t sound like it’s the bypass, could be but yeah I would try removing the restritor see if that increases the flow, the only other thing I can think of is, if you have any ball valves on the tubes, are they fully open/broke?

Has to be some blockage surely for the drop in pressure.