what's wrong with my r/o?

[zygote2k]

I have a 4 stage r/o (sediment, carbon, membrane, d.i.) that makes extremely low output. I took it all apart and blew air through all hoses and manifolds and even pulled the flow restrictor and checked it too. It makes the normal amount of water if I bypass the DI cartridge altogether, but if I put the empty cartridge back on, it goes back to weak output mode. My household water pressure is 40 psi and while I know this is low, at my other house I ran the unit just fine at 40. David Beasley lives across the street and runs his at 40 also. I currently have a 35 gpd membrane that will be rather slow, buy even when I switched back to the old 75gpd membrane, I have the same problem.

What's the deal?

[Origami]

What happens if you don't put the cartridge into the 4th stage housing, Rob? Are you installing the cartridge in the right direction?

[reefhunter]

what happens if you take out the sediment and carbon filters?

[zygote2k]

What happens if you don't put the cartridge into the 4th stage housing, Rob? Are you installing the cartridge in the right direction?

No cartridge in DI chamber still gets low flow.

 

 

what happens if you take out the sediment and carbon filters?

Didn't try it, but the problem seems to be after the membrane and before going thru final DI stage.

 

Can a flow restrictor go bad and allow too much water to pass thru?

[extreme_tooth_decay]

I currently have a 35 gpd membrane that will be rather slow, buy even when I switched back to the old 75gpd membrane, I have the same problem.

 

I wouldn't expect this part to change your production rate, since you are still using the 35 GPD restrictor (I wouldn't advise using a mismatched restrictor and membrane BTW).

[davelin315]

It's the PSI combined with water temperature is my bet. PSI starting at 40 will only drop further and below 40 renders most RO membranes useless. Factor in cold water (if it's not at around 76 then the membrane begins to decline in productivity) and that's probably your answer. Try and run the unit either in a warm bathtub so the water temp goes up or coil up a bunch of tubing and put it in a bucket with a heater and run it through there.

[zygote2k]

I wouldn't expect this part to change your production rate, since you are still using the 35 GPD restrictor (I wouldn't advise using a mismatched restrictor and membrane BTW).

As a matter of fact, I am using a mismatched restrictor/membrane combination. Maybe that is my problem. It all started when I switched membranes...

[zygote2k]

Good info for anyone changing membranes- use the proper sized flow restrictor, otherwise the water will not flow correctly.

Lesson learned.