I'm hoping somebody can point me in the right direction on fixing my RO/DI system. I purchased a typical 100GPD Ebay unit with storage tank; it was working fine for around 2 months. Now, it produces very little water, even after 24hrs - the 3 gallon holding tank never fills (I maybe get a gallon out of it). If I pull the tube out of the tank, the ro water sloooowly drips from the RO part.

I installed it under the sink, using the self piercing valve. I get about 60 psi going into the unit, however if I messure the water pressure just before it enters the RO membrane, it's barely detectable. I've taken it apart, and the filters, including membrane, all look clean.

Could it be the auto-shutoff valve?

I would think that 60psi would be adequate, if not ideal. Any thoughts on what else to check or any methods to troubleshoot the problem?

Thanks!

Jason

If the filters are in good shape there could be an obstruction in one of the various tubes/passages that carry water between the various prefilters,or the tube connecting the prefilters to the RO membrane, on my first RO/DI unit this happened to me, I got a little sediment buildup just before the membrane, flushing the tube with luke warm water dissolved the blockage. Just a thought

Yep, sounds like there's blockage somewhere. I believe I'd pull off the tubing before the prefilters and check that, and then pull ot the prefilters and check the passages between canisters. Also, just because the prefilters look OK doesn't necessarily mean they are. 60 psi should be just fine so something is stoped up.

i agree, it sounds like there is a blockage somewhere before the RO membrane. i would start with the first canister and work my way forward from there.

Thanks for all of the responses!

I did a little more testing: I measured the rate of the water coming out of the RO membrane, and it's about 6 minutes per cup. That's about 1 gallon per 1.5 hrs. If I bypass the prefilters and connect the source water directly to the RO unit, I get a rate of a little over 3 gallons per hour; that's closer to what I'd expect. Although I assume that there would be a little less pressure when flowing through the pre-filters, just not that drastic of a difference.

I'll have to take the prefilters off tomorrow and see if I can find a blockage that I didn't notice before when I examined them.

Thanks!

Jason

Well, I took it apart and I did not see any blockages. When I put it all back to together, I noticed the first two stages of the pre-filters fill up rather quickly, however the third stage took much longer (2 to 3 times as long). Is this typical?

I'm kind of out of ideas on what else to try with this unit. Any other thoughts before I scrap it? Thanks!

Jason

I think you need to rule out the filters now. I'd take out the prefilters one by one and try it. I bet even though they look ok, one of them is cloged. Either that, or you'll take all 3 out and it still won't work, in which case there is a block somewhere you missed.

Phurst -

That was my next move. Looks like I have a little weekend project ahead of me.

Thanks!

Jason

Are you sure you put the prefilters in the right order??

They need to get progressively smaller in particulate filtration as the water travels through them. In my case its 10 micron sediment -> 5 micron carbon -> 1 micron carbon (I think).

If you accidentally put them in reverse order the 1 micron filter will do all the filtering and clog WAY faster than necessary and slow production.

After a little trial and error, it turns out that the carbon filter was the culprit. I replaced that and it's back to working as expected. The filter didn't even look very dirty...until I compared it to a brand new filter.

I will verify the filters are in the correct order....although they were already installed in then unit when I received it and I don't remember seeing any kind of micron-size identification on the filters themselves.

Thanks again!

Jason

Cool, glad you figured it out :)