I have a series 3 in stainless with adjustable pressure relief set at 32 psi on my Tig welder the last 17 trouble free years. I can adjust from zero to 250 plus psi. I wonder what they want for that Procon magnetic drive pump? I bet in stainless it's a lot more than a March pump besides they do not like to be run dry at all. I have one spare motor with pump attached to a carbonator tank system, I recall it was pressure set at 180 psi this also has a adjustable pressure relief stainless Procon pump. I was told by a Procon rep years ago to keep the pump wet inside and the pumped fluid and seal under 200*F for maximum pump and seal life besides setting the pump pressure at the minimum pressure for the application. With this setup it would last many years, so far he is correct and now retired. This motor with pump for the Tig has a 12" square 3 row AC condenser with fan shroud and fan motor total cost $30 years ago as a whole unit. Just added a two gallon plastic lab tank, hoses, flow sight unit, fittings and pressure gauge. This sure beat the snot out of the asking price of Millers cooling towers back then. My friend spent $85 to have his stainless Procon pump rebuilt by Procon, shipping was included in the $85 four years ago. It is basically brand new as was mine and trouble free. Just don't run any grit or run 'em dry. A March would be a far better pump for brewing.
If you can get them cheap I bet there would be buyers on the www.millerwelds.com welding forum under the Ask Andy section wanting to build their own Tig coolers.