Check valve

[Wanabe1972]

I was told a while back to T into the concentrate line just before the concentrate needle valve and run back to the infeed to the HP pump for recirculation. I'm finally plumbing this and feel it needs a check/one way valve in this line. Am I correct or do I not need the check valve. Jeff

[mellondome]

You may want a needle valve on that line so you can maintain your desired pressure

[Bricklayer]

You don't need a check valve. I thought the same thing when I was plumbing mine but since it's inline and the hp pump is sucking it won't need a check valve. You will for sure need a needle valve in the recirc line to control the amount of recirc.
The way mine is plumbed is tee from concentrate line from membrane to a needle valve, then to a Flowmeter then to the inlet of the hp pump. This is a fairly high pressure line when it's wide open it's coming right off the membranes hp side so use good connections and hose when plumbing this.

[Wanabe1972]

Thanks that is how I have mine. A T off from concentrate to another needle valve through a flow meter and back to the HP pump feed line. Jeff