I saw a pump for sale by greatbrewseh.com that was a small DC pump with an AC adapter power source that pjumps about 3gal/min, that sells for half the cost of a March ($84 shipped, or $70 apiece for two). I recognized it as a version of a Topsflo 15 solar water heater pump, so being the cheapskate I am I bought one on ebay to give it a try. No adapter so I put a couple of alligator clips on it and ran it with a car battery charger. I want to try it for whirlpooling with an IC. Anyway, last night I heated 4gal of water in my kettle and recirculated it the whole time the temp was going up. The pump primed easily and runs silently. At 97C I measured it at 2gal/min and seemed to be generating a very nice whirlpool so I think it will work for my purpose. I’m going to put cam locks on the setup so I can use it on either of my kettles. I have it on a loop of braided vinyl hose with a ball valve on the outlet to adjust flow, although someone reported they screwed it right onto their kettle valve and it primed OK there. I may give that a try next, it’d really shorten the loop.
I have no idea if these things will stand the test of time, but supposedly a DC motor will last well and its made for continuous use so I see no reason why they won’t perform well over the course of time. Its half the cost of a March pump and it pumps at half the rate so I would suggest that if you can live with this rate, you might like to give these a shot.
