RO: What is the need for an ASV and/or flow restrictor for small RO systems?

[meredog]

Hi,

New member here. I live in Florida, on well water, where the TDS coming into the house is about 700 ppm. So all water related to human and pet cooking and drinking is RO. I have an undersink 4 gal storage tank system and a backup 20 gal storage tank system. I have been studying up on ASVs and flow restrictors, and I wonder if I should be using them? The original under sink system has both, but has always been a little problematic, and low flow and output (for a 4 gal tank). I installed the 2nd 20 gal system, and it runs like a well oiled machine without both ASL and flow restrictor, and it has a permeate pump. I test the TDS and maintain the filters properly on both systems. I am replumbing the undersink system so that it will be more easy to maintain without crawling into the cabinet, and plan to remove both the ASL and flow restictor. Is this a bad idea? I don't think I need either. Max pressure coming from the well is 40-60 psi. It goes through a sulfur aeration tank and water softener. I do not seem to have a 'won't stop draining' problem with either system.

I appreciate all advice!
Thank you,
Carolyn

 

[calibratedwater]

Hi,

New member here. I live in Florida, on well water, where the TDS coming into the house is about 700 ppm. So all water related to human and pet cooking and drinking is RO. I have an undersink 4 gal storage tank system and a backup 20 gal storage tank system. I have been studying up on ASVs and flow restrictors, and I wonder if I should be using them? The original under sink system has both, but has always been a little problematic, and low flow and output (for a 4 gal tank). I installed the 2nd 20 gal system, and it runs like a well oiled machine without both ASL and flow restrictor, and it has a permeate pump. I test the TDS and maintain the filters properly on both systems. I am replumbing the undersink system so that it will be more easy to maintain without crawling into the cabinet, and plan to remove both the ASL and flow restictor. Is this a bad idea? I don't think I need either. Max pressure coming from the well is 40-60 psi. It goes through a sulfur aeration tank and water softener. I do not seem to have a 'won't stop draining' problem with either system.

I appreciate all advice!
Thank you,
Carolyn

Hi Carolyn - (I realize this is an old thread) Without knowing more about your specific RO, I can only make some general comments.
The ASV - auto shut off valve - is a device that controls the flow of water to the membrane. It turns the system on and off. Most small domestic RO systems use an ASV. Some domestic RO systems, and probably most commercial RO systems, use an electronic shut off valve. If your RO system has an electric pump, it probably has an electronic shut off valve. Your system will have one or the other.
Some RO systems with a permeate pump, a type of non-electric pump that uses water pressure, and may or may not have an ASV. The permeate pump acts as the shut off valve.
A restrictor is needed on the discharge/waste line to create back pressure against the membrane. This can be a fixed restrictor, an adjustable needle valve (also called a throttle or choke), or an electronic valve. If you remove the restrictor, your RO system will not make much water if any. Additionally, you would be wasting a ton of water.