RODI pressure

[Nick Rose]

I have a question about the pressure coming from my RODI unit. I have the pressure gauge between the carbon block and the membrane. The pressure is just below 50 but when I attach the gauge to the individual canisters and also the faucet it shows just below 60. Is this normal?


Pressure from faucet

Pressure from sediment filter

Pressure from first carbon block

Pressure from second carbon block

Pressure when attached between second carbon block and membrane

 

[Webslinger]

you're within range

 

[Reef.]

I guess going through all those stages you are going to loose some pressure, it’s not much so I wouldn’t worry over the small drop.
You could improve that pressure for better results, 50psi is just within acceptable range, if you used a booster pump to get around 90 psi you would see a marked increase in the rate of production.

 

[RM24]

I bought a booster pump and I'm getting around 90 psi. Best upgrade so far. I highly recommend it. Membranes are more efficient under higher pressure which means your resin will last longer and water is processed faster.

 

[Nick Rose]

I mislabeled the pictures. The fourth picture is when I test the pressure with the sediment and 2 carbon blocks connected without the membrane it’s just under 60 but once connected to the membrane it drops below 50. Does the membrane cause some type of back pressure or something.

 

[Reef.]

I mislabeled the pictures. The fourth picture is when I test the pressure with the sediment and 2 carbon blocks connected without the membrane it’s just under 60 but once connected to the membrane it drops below 50. Does the membrane cause some type of back pressure or something.

I would think it does, the water has to force its way through the membrane, that is how it works, the harder the water pushes against the membrane the more efficient it is. Less than 50psi is not great, most membranes recommend at least 70psi I believe.

 

[mann1139]

I mislabeled the pictures. The fourth picture is when I test the pressure with the sediment and 2 carbon blocks connected without the membrane it’s just under 60 but once connected to the membrane it drops below 50. Does the membrane cause some type of back pressure or something.

With the tiny tubing we use for RO/DI systems, there is pressure loss every inch. I've done the same test you did, and had similar results.

When the system is running, the pressure will be lower, because one end has a pressure of '0'. Once the system is shut off, everything will try to 'fill up' to line pressure, unless it is valved off first.

 

[Nick Rose]

With the tiny tubing we use for RO/DI systems, there is pressure loss every inch. I've done the same test you did, and had similar results.

When the system is running, the pressure will be lower, because one end has a pressure of '0'. Once the system is shut off, everything will try to 'fill up' to line pressure, unless it is valved off first.

Glad you had the same results. I was trying to figure out when to change the sediment and carbon blocks. The highest my tap tds is 20-25. Those filters are hitting their 6 month mark. I test the waste was for chlorine and its still showing 0.