Check Valve Position

It depends on the check valve and application. What type of piping and what material are you talking about. A little more info Please.

You can place it in the vertical, but only as long as the flow is going up. If you have it pointing down, then the check valve will not work very well. The check in the valve will want to fall forward at zero flow due to gravity and if you only have a little reverse flow, it will not be enough to seat the check in its seat and stop the reverse flow. Even if you have a spring loaded check valve its not a good idea since the head of fluid could force this open.

So to answer your question, yes and no.