7 Lbs of air should be fine but you can back it off to about 5 if you want. The reason it stops producing at 20psi is that there is an auto shutoff connected between the intake tubing and the output. When pressure builds in the output line it shuts off the input so that leaks don't occur. This is a nice feature especially when using a storage container like a trash can for RO water. When the float valve shuts water flow stops before pressure is high enough to cause a problem.

 

There shouldn't be any valve on the waste water line. This should just go directly to a floor drain or to your sinks drain via a saddle connector.

 

If you remove the tubing from your storage tank the RO unit should make water continuously. When connected to the storage tank the unit will make water until the tanks capacity is reached then it will stop. This isn't usually enough water for our needs. That's why I suggest putting a Tee in the line just before the storage tank and running a line to another storage container. You can get a float valve from a LFS or Marine Depot that uses a 1/4" push connect fitting and a 1/4" Tee fitting form Home Depot or Lowes also with push connect fittings. When your container is full the float valve will close and pressure will build in the storage tank and line shutting off production of RO Water until needed.

 

Check out this Video on RODI units from BRS. It will show you all the components of the various RO and RODI units. http://www.bulkreefsupply.com/store/video?file_name=52

 

They also have an instructional video which should answer any questions about setup.

 

 

when i first got tank, i filled it with 7psi of air. it reaches about 20psi when full. is 20psi to low? what do i want the tank pressure at?

waste water line has no valve to adjust restriction.

 

 

when working correctly, will RO units give a steady stream all day? or will it just give you the 2-3 gallon tank capacity of water, until it re-pressurizes?

What I would suggest is that you get a large storage container (I use a 35Gallon Rubbermaid Trash can) and tee of the line between the storage tank and the RO unit. Then get a float valve and attach it to the inside of the container at the height you want the water to stop. Now run a piece of tubing from the Tee to the float valve. 

This will allow the storage container to fill with water before the pressure in the tank stops flow. When the water reaches the float valve it will close the valve and when pressure is high enough the Auto Shut Off valve on the RO unit will stop production of RO Water. Now you will always have 1 gallon you can take from your storage tank as well as all the water available in your storage container. 

This is probably clear as mud but I hope it helps. Maybe this pic will help. You can see where my line is Tee'd off and runs to the trash container in the picture. Good luck and feel free to give me a call if you have any other questions.

If you can give us some more details on the unit you have it probably will help us to better answer your question.  What model, the gpd, was it new/used, etc.

 

only problem i'm having is im only able to get about 1 gallon of water every few hours.

i thought maybe i just need to wait for it to fully pressurize the tank, so haven't touched it since last night, and was still only able to get maybe just 1 gallon worth of water.

any ideas?