River water system - separate water/air tank?

[Blavidais]

Hello all,

So I successfully set up my drain back system for my river however I get hesitation, around 30 seconds at most before the water makes it back up from the river—then it runs indefinitely.

Right now I am using an 80 gallon waterworker pressure tank that holds—I believe—25 gallons of water. The run is approx 300’ up from the river. Based on that physics it’s just not enough. Is there a way to set up separate air and water tanks so I can avoid this hesitation? Maybe like a 50 gallon water tank to be safe to never have to worry about running out before the water makes it back up?

It sucks to eat the 600 bucks for the bladder tank and I’m grateful to have a successful self draining/working system not being a plumber; but it’s going to get old waiting for water supply during showers.

 

[LLigetfa]

You just need to let some air out so that the tank doesn't empty before the water arrives. Also, I would suggest a CSV so the pump doesn't cycle during use and drain back needlessly.

 

[Sponsor]

 

[Valveman]

Like LL says a CSV would keep the pump running the entire time the shower is on, so it would not be cycling and draining back. Reducing the air charge in the tank will also cause it to supply water for longer after the switch starts the pump. Will take a little trial and error as you want to keep as much air in the tank as possible. Start with really low air pressure in the tank. Note what pressure the system is at when the water finally reaches the check valve. Then adjust the tank aid pressure to be a few PSI less than that point.

 

[LLigetfa]

Two things to keep in mind if reducing the air precharge is that it may overstretch the diaphragm so reducing cycling with a CSV increases the longevity of the tank. Some tanks have internal dome limiters to protect against overstretching in which case the last few PSI pumped in can spike upward quickly creating water hammer.