pumps

I don't doubt that. I get the impression that there is a high variance in success for March pumps.

 

Cavitation sounds like you are sucking air. Have you resealed all of your connections?

 

I think it just takes some practice getting them primed. I used to beat my head against a wall the first 4-5 brews, but I figured out a process and it works beautifully. I always thought cavitation sounded more like a small forest animal being tortured.

 

Could be, though it's a pretty simple design that I wouldn't suspect such variances from. I had similar problems, and the concurrent cussing fits, until I discovered the head was essentially mounted upside down (though it sounds like that's not the case with yours). I added the big impeller at the same time and the difference was like night and day (not sure which had the bigger impact, though I suspect it was the orientation of the head). Priming still takes some technique, but it's not nearly the chore it once was, and my flow rate was greatly improved.

 

I'm looking to get the bigger impeller...is it just the March 815 impeller? Any other pieces needed to retrofit?

 

The impeller I bought was sold as a HF replacement for an 809 pump. My understanding is that it's the 815 impeller, but I don't speak with authority on that. It's a drop in replacement - no additional considerations.