March 815 ss flow issue (primes fine)

This is the stainless head with 3/4" center inlet. For a year now, the pump primes fine and will pump with ball valve 0-60% open. Any more than that and the water stops moving.

I have the same qd's as Kal, same pump, silicone hoses, but the only difference is it is mounted in a toolbox sitting on the floor instead of on a stand. Standard counter height to ground distance for pump inlet. There is not a pick up tube to contend with either.

I decided the problem must be the small qd's. I wanted a second pump anyway so bought the same one and equipped it with cam lock qd's. Just tried it and I have the same issue.

I have no problem priming the pump at all. It starts pumping immediately and will continue pumping until I try to open the valve all the way.

Ideas? I have a hard time believing it is the pumps. They were bought a year apart.

Edit: This happens with cold water as well as brewing temps. Thought I'd throw it out there since I've read of similar issues here but always only at boiling temp.

Had a lengthy chat with Walter at March. I can't praise him enough for his knowledge and patience.

So the magnet sits on the magnet shaft at a precise location relative to yhe pump head and impeller. I removed it to get it through the pump box wall. By removing it and just putting it back on I changed the interaction between the magnet and impeller.

As I figured, user error.

I owe it to Walter to put up a few pictures. I adjusted the magnets forward and boy do those pumps move some water. 9 gallons in 65 seconds on Pump 1 (camlock qd), 68 seconds on Pump 2 (ball bearing style qd). Much better than 3-4 minutes with the valves closed half way.

So the toolbox is a 16" Craftsman metal box. I cut holes just big enough for the magnet shaft without the magnet. I would recommend anyone else cut the hole big enough for the magnet to fit though too.

I also cut 4" vent holes in the side, gave the whole thing a black hammered finish paint job, and covered it with sheet aluminum.

In this process I discovered "blue" thread tape. (Oakley Megatape) It is much thicker than the white crap and doesn't shred to pieces removing it.


Thanks again Walter!


Edit: Ha! Just realized the pictures are the old ones and demonstrate the magnets installed too far back on the shafts.

Hey that's a nice setup ya got there
For anyone else wanting to do this type of tool-box pump setup.....the face of the drive magnet on the motor should be about 1/16" below the face of the motor bracket....so if you put a straight edge on the motor bracket where the pump would normally sit....then adjust the magnet until its slightly below the bottom of the straight edge.....and for those that want an easier way to cut the holes in the tool box here's a template you can use.....just set the printer to print it 1:1 or full size and you should be good to go

View attachment 809 Box Template.pdf

Thanks! To do it again, I would definitely cut the hole for the magnet as you suggest. It wasn't that hard to monkey with the magnet though after you told me how to set it.