DID i kill the RO membrane?

[vivek]

My set up includes a RO/DI 4 stage unit connected to a float valve in the sump to top of evaporation (which is significant as i am running a fan on the sump for temp control) When the RO is actively adding water the pressure on the gauge reads 70 which is good and stays that way. So i know i have no low pressure issues on the supply side of the unit. But once the sump is topped off the pressure drops to nothing even though the water faucet is open all the way. At this point even though the water is getting filtered and is of good quality (tds 0) i am concerned that the pressure gauge is reading zero. Could this be a problem? My first RO membrane lasted only 9 months. (tds reading in my tap water is usually 360). So am i going to kill this new membrane again with this setup? Anyone else use a float valve connected to the RO/DI output to top off water in the sum

[kgross]

Sounds like you have a shutoff for you RO that is connected in front of the pressure gauge. This way when the output is stoped, the shutoff turns off the water going to the RO so you are not wasting water to drain.

If you did not have the shutoff the water would still flow to the RO, but all if it would flow out the waste line and you would waste a lot of water.

Kim

[vivek]

Originally posted by kgross
Sounds like you have a shutoff for you RO that is connected in front of the pressure gauge. This way when the output is stoped, the shutoff turns off the water going to the RO so you are not wasting water to drain.

If you did not have the shutoff the water would still flow to the RO, but all if it would flow out the waste line and you would waste a lot of water.

Kim

You maybe right. But i do not know if i noticed it. But when no RO water is being made there is no water coming out of the waste line. But with my RO connected to the float valve in the sump the RO unit has frequest starts and stops as the water in the sump is constantly evaporating. The pressure gauge never reads above zero for these short runs of filtration thru the unit (though it normally takes about 5 minutes for this gauge normally to register the pressure in the RO system.

Any one has any thoughts if this is a bad idea to connect my RO/DI unit to a float valve in the sump for automatic top off (i.e. will it kill the membrane)

[kgross]

If it is connect properly it will not damage the membrane, but you will have TDS creep issues. But to answer you question we would need to know how your RO system is setup, does your system have a pressure storage tank? We know it has a shut off or your waste line would flow water all of the time and your pressure would never drop to zero. if you have a storage tank that would explain how you could flow some water without the RO turning back on. Just having a float valve connected properly will not harm your membrane.

Kim

[vivek]

Originally posted by kgross
If it is connect properly it will not damage the membrane, but you will have TDS creep issues. But to answer you question we would need to know how your RO system is setup, does your system have a pressure storage tank? We know it has a shut off or your waste line would flow water all of the time and your pressure would never drop to zero. if you have a storage tank that would explain how you could flow some water without the RO turning back on. Just having a float valve connected properly will not harm your membrane.

Kim

My system is very simple. Faucet connected RO unit input directly. And the RO unit output is connected to the float valve directly in the sump. I do have a T connector with a manual shut off valve to a 32 gallon reservoir to make RO water for water changes that i manually control.

What is pressure storage tank?

Do you think i need this from spectrapure


http://www.spectrapure.com/St_alc_p1.htm



vivek