Mr. Pump Box

As my home brewery has gotten more and more towards an all electric set-up, I have been trying to find ways to simplify my brewday and make my brewery as modular as possible... on the cheap.  For less than the cost of a second March 809 pump, I was able to build a 2 pump box with full flow control using a couple of parts off of Amazon, as well as a few items I've had laying around the house.

The really nice thing about this pump is that the flow control is completely adjustable.  The dimmer switches on the box allow me to adjust the flow from zero to 1.5GPM.  Sparging and transferring is much easier with less of a chance of cavitation.  The toggle switches aren't necessary, but allow me to ensure the pumps are off to reduce the chance of burning out.

The only thing I would have done differently is to mount the pumps to a chunk of wood on the bottom of the box.  The pumps have mounting holes, use these instead of trying to use the inlets & outlets as your seals.

Behold, in all its glory:  Mr. Pump Box

Plan View


Parts list:


Part Name Part Number   My Cost  Source
Nema Enclosure NBF-32018  $   25.40
Pump zjchao-6935824c  $   20.60 
LED Power Supply 821418829416  $   15.50 
Dimmer  T90040  $     5.98
Waterproof SPST CXCP190KB  $   11.99 
Outlet Cover MM710C  $   12.41 
RV Plug RVA4012  $     5.00 
Street Elbow M603-08  $     7.12
Plastic Fittings 12010308088  $     9.23 
  Total  $ 146.93  

I used whatever low voltage wire and screws/nuts I could snag from work, had all the other fittings in house already, including the junction box, washers, camlock fittings, PTFE tape, wire nuts, WAGO connectors, electrical tape, and command strips to stick things in place.

As for the build:

1) Measure/cut all holes as best you can.  This is what the extra washers are for - in case you fucked up like I did and forgot to take draft angles into account when slapping a ruler on the box..  Use a step drill, or if you have it, a knockout punch for the inlet/outlet locations.

2)  Wire everything up.  Since the dimmer switches are hidden under the box lid, you won't have access to them after they're mounted.  The wiring is extremely easy, and since it's 12v you don't have to worry about getting zapped.  Order goes:  Male Receptacle, Power Supply, Toggle Switches, Dimmer Switches, Pump.  I like to use WAGO style connectors where I can.  They cost a bit, but make wiring a breeze.  I'll also be switching out my crap wiring to use spade terminals for more secure wiring.  Also, do what I didn't and get some wire wrap so you don't pinch your damn wires.


3)  Mount everything.  Again, not too hard here.  Toggle switch is threaded to the box lid, dimmer switch needs some machine screws to hold them in place.  If you have O-rings, put them where you can to ensure a good seal.  Water-proofing is the goal here.  Don't forget to use PTFE tape on all threaded components.

4)  Seal everything that isn't gasketed with silicone

5) Label in's & out's.  I haven't done this yet, I'm waiting for work to get more label tape in.

6) Put on your dimmer switch knobs. Silicone in place if they tend to slip off (like mine)

There you have it, your very own, cheap pump box for less than the cost of a single March 809 pump.

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