The 3 gallon still holds 2 gallons of liquid, leaving a 4" headspace. The water lines are pretty short, so I ordered 25 feet of 3/8" ID silicone tubing to reach my sink from the stove (about 10 feet for each line). The unit barely fits under the microwave oven above my stove, if I orient it just so. There are no instructions for using the thumper. Apparenty it's best to have a tube from the inlet to the bottom of the pan, so I bought a 3/8 HBX x 1/4F brass adapter, and attached about 4" of the 3/8" ID silicone tubing. The video on Amazon provided by the manufacturer mistakenly shows silicone seals placed on the inside of the boiler lid ("onion top"), but they should be on the outside. The hot vinegar run discolored the inside of the brass connectors, and created a reddish residue that should be cleaned off. The unit needs to be partially disassembled to do this. There was also metallic residue on the thermometer threads and nut. The instructions are in broken English, but not too weird. The rye whiskey recipe calls for a gram of ammonium fluoride(!), but they mean ammonium chloride. The bottom of the boiler isn't quite flat, so the unit rocks back and forth on my glass stovetop unless I wedge a couple forks under it. Overall it is reasonably well made, for the price.
robert 
