AFW ASV90 ASV90-14Q 90% Auto Shut Off Valve for Reverse Osmosis ASV for RO with permeate Pump, 1/4", Gray

Note, only buy this if you have a permeate pump on your R.O. system (an upgrade everyone should consider). My incoming pressure is 60 lbs, my old ASV had my tank at 27lbs, this took it right up to 52 lbs., no instructions but the plastic body does have the ports labeled. My only complaint so far is the turn ON pressure is too low, it waits too long to come on let's the holding tank pressure drop too much which means inconsistent output. At least the ice maker seems to be recharging faster and when it's at full pressure really fills a glass.EDIT: After my disappointment in the 30 PSI differential between the turn ON pressure of 17-20 PSI and the turn OFF PS! of 47-50 (which I was happy with), I changed the lines so the ASOV was controlled by the Permeate IN instead of the Permeate OUT port, and now the pump kicks ON at 43 PSI and OFF at 47 PSI so the tank stays near max pressure all the time, except when I have a large draw like filling a cooking pot. NOW I am quite happy with this ASOV. I have included both the traditional and my revised plumbing diagrams for reference.

Pros: Looks to be well built. My incoming water pressure is 58 psi. Tank pressure is 51, so about 88% with permeate pump.Cons: No instructions. Not the same port locations as OEM.Overall: A keeper. One reviewer posted a connection diagram (many thanks). Follow it and you're good to go.

I have a fairly standard RO setup with a 50GPD FilmTec Membrane, an ERP-500 Permeate Pump, and 75PSI of feed pressure. Without an ASV my TDS would creep all the way up into the 180s (~220-300 softened feed TDS) and with your standard generic white ASV's I would get shutdown way too early for a system with a permeate pump. I decided to give this ASV a go since I was getting tired of doing weekly tank flushes and wasting a bunch of RO water. I still get plenty of production for my needs, the ASV performs somewhere around 75-80%, and my TDS has stopped creeping (~20 TDS floating average).I still plan on doing weekly partial tank drains refilling the pet's water fountains, but I'm very pleased without having to do a full tank drain weekly just to keep the TDS reasonable.

I have a 50 gpd ro unit with a permeate pump. without an aso my ro tank fills to 60 psi with my feed line at 65 psi. This aso shuts off at 35 psi tank pressure. This is about 54%, not even close to the 90% specification. If this aso shut off at 50+ psi, I would be happy, but 35 psi won't cut it for me as it severely limits how much water I can store in my tank. This manufacturer should be sued for false advertising.UPDATE: So I decided to take the aso apart, and reverse engineer it. The shutoff mechanism depends on a internal piston with different size faces which are pressure isolated from each other. The tank side face diameter is ~ 0.560 in. or ~ 0.246 sq. in., The supply side face diameter is ~ 0.425" or ~ 0.146 sq. in. This is an area ratio of ~ 60%, which is the measured pressure shut of point of the valve in my possession. Calculation shows that the tank side face of the piston would have to be in the range of ~ 0.450 in. to give a 90% shut off point. This is definitely outright false advertising since the valve is not mechanically capable of the manufacturers 90% specification.

Not a 90% valve. The normal Apec 65% valve closes at 45psi and this one closes at 47psi.... This is with 72psi inlet pressure. They both open around 30psi so no luck keeping my ice maker happy. Seems like a high quality part, despite the misleading description.

I have my under-sink RO system connected to the fridge as well as a hot water tank.The stock ASO didn’t allow enough pressure to maintain respectable flow so I got a 50GPD permeate pump. The pump solved the pressure problem but resulted in TDS climbing from 5 to 60.This ASO valve kept the TDS down at 5 while retaining the benefits of the permeate pump. I haven’t measured if it’s 90% but I’ve seen a dramatic improvement. Best addition I’ve made to my RO system.

I don't notice any difference between this ASV and the standard white one that came with my RO unit. If the inputs and outputs were in the same places I would have returned it but since these ones do a u-turn for the output I had to cut my tubing and redo half of what was going to the ASV

Item is very poorly labeled, and there are no instructions included on how to install this. that being said, you can look up other auto shut off valves on youtube. the difference being, this is a u-style return. the input and out are on the same side of the valve, respectively. i have an input of around 65psi and my holding tank is holding around 40psi. i installed a permeate pump for now, and will be installing a tds meter later.