View Full Version : Cartridge flow restrictor

01/14/2009, 08:22 AM
I purchased a cartridge flow restrictor and a new membrane a few months ago to turn my unit into a 150 gpd unit.
It was working great for a while but now it only makes around 50 gpd again.

It's not a cold weather thing because we have had mild weather until just a week ago.

What could have happened?

Buckeye Hydro
01/14/2009, 08:25 AM
What is your pressure? Tap water temperature?


01/14/2009, 11:54 AM
55-60 psi

Temp has been around 70-75 degrees. Right now it's 60 degrees because we're having a cold front, 40's is cold here.

Buckeye Hydro
01/14/2009, 04:42 PM
IS that your water temperature or the air temperature. We need the water temp.

Buckeye Hydro
01/14/2009, 04:43 PM
are you reading that water pressure from a gauge?

01/14/2009, 06:08 PM
That's the water temp ; ) Today the water was 60 degrees which is colder than usual due to the cold front we're having.

I guess my above post was confusing. 60 degrees was referring to the water temp. When I said that 40s is cold I was referring to the air temp.

Yes I have a pressure gauge on the unit.

Buckeye Hydro
01/14/2009, 06:25 PM
OK. That pressure (55 psi) is on the very low end for that membrane. The temperature of course is much lower than the 77 degree spec for the membrane. Those two combined are likely causing a pretty substanitial decrease in the production of the membrane.

Of course you might have other issues but we'd need to look into the situation in more depth to figure that out.

What is the tds of your tap water?
Do you have a softener?


01/15/2009, 01:30 PM
Usually the psi is above 60. Right now the psi is 65. The other day it said 55. I'm not sure why.

I remember asking you guys if I had enough pressure before I purchased the membrane and you said it was fine. I think you said above 60 was good if I rememeber correctly. I think in the summer it was 65-70 psi but I'm just guessing by memory.

What do you mean by 77 degree spec for the membrane? Does anyone have 77 degree cold water from the tap? I'm confused.

The tds are 100 from the tap. I do not have a water softener.

Buckeye Hydro
01/15/2009, 01:53 PM
65 psi is spec for the membrane - 60 or above should be good - 55psi would be at the very lower end of OK.

All membrane manufacturers spec their membranes at 25 degrees C or 77 F. Colder water means less production.

Have you measured the production from your membrane (or did you estimate it? - which is hard to do with any accuracy...)?


01/16/2009, 09:23 AM
I measured it per gallon filled and then per 40 gallons filled and did the math.

Buckeye Hydro
01/16/2009, 04:56 PM
So you sometimes have low pressure, and you have low water temperatures (that are surely worse this time of year than others). In addition to that do you have water conditions that would tend to foul the membrane? Well water? Iron? High hardness? Manganese?

The other thing you could do is check for biofouling. Open up the membrane housing and see if you notice any slime. Check the ends of the membrane for a foul odor.


01/17/2009, 03:13 AM
The other day was the first time I noticed the pressure under 60 psi.
The water from the tap was fairly ward during the summer and fall but I didn't measure the temp at that time. I'm just guessing on that.

It's not well water and I don't know about the mineral content, only that it reads about 100 tds when tested randomly.

I changed the cartridges recently and the membrane was changed over the summer.

The other day we opened the membrane housing to see if anything was loose and it seemed okay. Interestingly enough it seems to be putting out more water now, even with the cold temps. Tomorrow I will measure the output and see exactly what it's producing.

Thanls for your help so far. I'll let you know once I measure the output.