Need check valve fittings?

[Hunt4sap]

The elbow fittings that came with my RO membranes have a check valve built into them. Do I need this or is it going to be a problem if I use them?2212722128
Can be read on right side of paper.
Not sure if I use them if it will cause it not to work?

[fred]

If they are there, they are meant to be used. What did you get? And where did you get them from?

[blissville maples]

Perhaps they are trying to prevent a potential issue; if your water tank is higher than the machine, and the end is submerged you could draw all that water back into the machine and depending on your valve arrangement that liquid could go to an unintended place!!

That's the only thing I can think of!! Otherwise you shouldn't need any check valves.

[Hunt4sap]

If they are there, they are meant to be used. What did you get? And where did you get them from?
What I'm referring to is in the pictures I have attached that show the check valve in one of the elbows

[Muddy Bottoms]

Trying to blow the picture up, doesnt it say "OR" checkvalve

[Hunt4sap]

Trying to blow the picture up, doesnt it say "OR" checkvalveyeah "or" which makes no sense because the elbow that they come with has a check valve built into it

[carls47807]

The check valve with the pink ring around it is really only used for domestic water applications. When the RO is used to make water in a pressurized tank, it stops the tank from draining back through the RO when the booster pump shuts off (or supply water turns off). You can put it on either outlet, but it isn't necessary. Do not put it on the inlet.

[Hunt4sap]

I'm just making sure by using it in my sap ro system that it won't create an issue ( I'm using the fittings that came with the membranes so one will have a check valve...)