RO/DI Pressure Switch Problem

[abbypoodle]

I just installed a pressure switch before a T that goes to my pressure tank for drinking water on one side and DI on the other. I am also running an auto flush valve and an aquatec 8800 pump. This setup works well on the DI side but for the drinking water it will repeatedly shut on and off and will never stay off.



Any ideas? My configuration is pretty typical

 

[Flippers4pups]

Bump

 

[abbypoodle]

I think I’ve narrowed down the culprit but not sure how to proceed.

Permeate Pump

I’ve moved the pressure gauge to the product line before and the product line after the permeate pump and it happens on both.

The booster pump shuts off but the permeate pump gives one more click, which drops the pressure enough to fire up the booster pump and then we’re stuck in a loop.

 

[abbypoodle]

I’ve sent an email to both Aquatec and BRS. I called BRS and they said that having a booster pump and permeate pump is not that common but my setup appears to be correct and should work.

Just to reiterate - the shutoff works when I’m turned to DI and it only fails when pointed toward my pressure tank and air gap faucet. I am going to remove my check valves and try again

 

[abbypoodle]

If I turn off my pressure tank valve it works. I have eliminated all check valves and can say with 100% confidence that the shutoff works when my pressure tank is closed.

How could an over or under pressured pressure tank cause this issue?

Getting closer!

 

[abbypoodle]

I removed the permeate pump and now it’s working. The booster pump shuts down when the pressure tank is full and will turn back on when I’ve used a certain amount of water from the pressure tank.

I was hoping to have both a booster pump and permeate pump but it looks like that might not be doable.

Hopefully this is helpful to someone.

Thanks!