i installed this backflow preventer. did i do it right?

I have the direction of flow right? I am not getting waste water in the dump pit, but want to sure.

Don't know about the BFP, but you used the wrong Fernco connectors. The connectors for above-ground applications are supposed to be the banded couplers. Now, these may work OK, but your inspector may not like them. My limited experience with BFP is for irrigation purposes and are obviously totally different, but I would think there would be an arrow indicating the direction of flow stamped on the case.

What Gary said. Also, you typed "dump pit" but I'm going to guess you meant sump pit. Pumping sump water into the sanitary sewer is illegal in many places.

The dump is from a tub. The connectors came with it. But I can see shy no hubs would be better.

Those connectors help absorb the pressure change when the pump starts, otherwise it might push the pipes apart. They are always used with that type of check valve. The ones on the 'large" pipe, however, are incorrect.

I didn't put those in, but I can't imagine getting a no hub in there.