Pump Location

Do you think it makes any diference where you put the pump on the return on a radiant zone. Before the mixing valve or after. All mine push the return water toward the mixing valve. My new shop would be a cleaner install if I put the pump where it will pull return water past the mixing valve.

I have always put the pump after (downstream) the mixing valve.

That what I am going to do then. My pump will actually be right on the return header it has an internal flow check in it.