Hi Drskint

I have only installed 2 of these and had no issues so I can't really advise here, but see below for more...

Check out this link for more info.:

https://www.askmehelpdesk.com/plumbing/watts-premier-reverse-osmosis-tank-wont-fill-water-continues-run-318082.html

You can also check out this manufacturer's link for more information:

http://www.tdsmeter.com/education?id=0008

A number for technical support is available at this link.

Good luck!

Mark

Continuously like 24/7? These units do run a good bit of water down the drain when they are recharging, could be for up to an hour but more than that I'd guess you have a stuck valve. How old is this unit and how long ago did this problem pop up? I too have only installed 2 of these RO systems and was surprised when it ran for so long.