View Full Version : Pressure loss after changing R/O pre-filters

05/09/2014, 06:01 PM
I recently replaced my 1 micron sediment, granular catalytic carbon, and carbon block pre-filters with new 1 micron sediment, chloraguard block, and carbon block filters.

pressure before-60psi

pressure now- 45-50psi (which also causes my product water to have a couple more TDS from 3 before to 7 now) source water tested same at 220.

I installed the sediment filter and chloroguard block and flushed for 10 mins, discarding water after second stage, then installed the carbon block and flushed another 10 minutes discarding that water.

Where could I have gone wrong to cause the pressure loss?

Buckeye Hydro
05/10/2014, 07:14 AM

So the only thing different is you swapped out the CGAC for the Chloraguard. Because the GAC does offere some resistance to flow, the most pressure drop you should see is something along the lines of 2 to 3 psi - definitely not 15 psi.

Something else is going on...

Maybe your neighbor turned on his huge irrigation system? Or you had a couple showers running in your house?


05/11/2014, 03:59 AM
Something along those lines was my first thought also. I have tried making water a few times now, at different times of the day, but it's still low.

Buckeye Hydro
05/11/2014, 04:13 AM
Is your flush valve cracked open a bit maybe?

05/11/2014, 07:23 PM
I did readjust the waste water ratio, since I noticed I was running almost 6 to 1, but now its 4 to 1.

I usually open the flush valve for a minute or two before and after running the system, but I am pretty sure the valve is being closed fully.

Buckeye Hydro
05/12/2014, 02:24 AM
If you went from a 6 to 1 to a 4 to 1 that would have increased your pressure. Might want to check this out - my guess is that the pressure change has something to do with what you did to the flow restrictor. Do you have a needle valve on the waste water tube?

05/12/2014, 06:49 AM
Yes, I do have a needle valve. Actually I purchased a new one from your website recently, because it looked like it would be easier and more precise to adjust than my current one I was using. And I suppose in that perspective it was, but it was dead silent, whereas the cheaper one that came with the system makes a hissing noise when running. I grew to like the noise, because being the absent minded person I am, without the noise I know I would forget that I had turned the R/O system on. So I swapped it back in.

When I first put the newer needle valve in, is when I noticed the pressure drop, I even tried closing the valve much more than usual, but it didn't seem to make much difference, which is when I assumed I had done something wrong putting the filters in. Is it possible I installed the valve flowing in the wrong direction? I didn't think it mattered.

Buckeye Hydro
05/12/2014, 07:00 AM
Now there's a new one... I can hear the conversation around the water cooler here this morning... Customer liked the noisy valve better... Ha! :)

Flow direction doesn't matter on the two valves you mentioned.

Closing the needle valve should have a dramatic effect on the pressure shown on your pressure gauge. If closing/opening the inexpensive needle valve doesn't change pressure, the valve should be replaced - its striped.

Check to make sure you're at something close to a 4 to 1. I'm pretty sure the difference you're seeing in the pressure has nothing to do with the new filters, and everything to do with the adjustments you made in the flow restrictor.


05/15/2014, 09:31 PM
Well, my pressure is back up to 60, strangely enough I didn't adjust or change anything.

It did seem at the time like water pressure in the rest of the house was slightly less, but it wasn't anything I was measuring, so maybe it was my imagination. Is it common for city water pressure to vary from time to time? I have my filter installed under my kitchen sink, and don't look at it all that often.

Anyway thanks for the quick responses

Buckeye Hydro
05/16/2014, 03:30 AM
Yes - city water pressure can fluctuate - for many people it's a daily event, but only something you'd notice if you monitored a pressure gauge.