[krazy]

Some brief updates on the pumpology:

The pump has been running more or less nonstop since I bought it now with little trouble. I've still never had a single leak from anything on or directly attached to the pump. I actually just disassembled it tonight to have a look at the impeller. If you look at the pictures I posted initially (or your own mag-drive impeller), you will see that there is a small washer made of some kind of synthetic material that rides on the shaft between the impeller and one of the rubber end bushings. A few months ago, mine simply wore out. The pump started to make a rattling sound that was initially faint, but grew worse and worse by the day. I eventually shut the machine down, drained the loop, and tore open the pump. Everything looked fine, but I noticed that when I stuck the impeller assembly into the (removed) impeller housing, I could get the impeller to scrape against the inside face of the housing without much trouble at all. I popped one of the busings off of the shaft and took the pieces off of the shaft. The washer was worn right down to nothing for some reason. It seems that either the suction of the pump or pressure from the magnets pulls or pushes (respectively) the impeller assembly's magnet towards the inlet and was putting enough pressure on this washer that it simply ate right through it. All that was left was a paper-thin wafer with part of a rim around it that escaped being worn to nothing.

Since my computer couldn't run without a pump and I don't exactly have another workstation handy, I decided that I would have to fix the impeller pronto. I scrounged in the workshop, hoping to find something synthetic and the same size as the former washer, but all I could come up with was an ordinary steel #6 hardware store washer. It fit onto the ceramic shaft PERFECTLY and was also the same outer diameter and approximate thickness as the original deceased washer. I worried about rust and corrosion for about 30 seconds and then slipped the washer onto the shaft in place of the original one and reassembled the pump.

When I broke down the pump tonight, several months later, the washer was still there and still doing it's job well and wasnt even very rusty or corroded. The water I drained had a very fine black sediment that settled into the bottom of the dishpan I used after a few minutes of sitting still on the floor, but I don't know if it is related to the steel washer or something else in the loop. (the loop is aluminum-free and just has a few copper blocks, acrylic tops, clearflex tubing, acrylic reservoir, and a soldered copper/brass heatercore and the pump, so...)

Now the impeller assembly is rattling again (the reason for my disassembling it) but it is not scraping on teh impeller housing face. It seems that the actual individual impeller component no longer has tight tolerances on the ceramic shaft and is rattling around like a dying bushing would. If I stop and restart the pump a few times, I can pretty much get it to quiet down on a hit-or-miss basis, but I am ready to order a spare impeller assembly (or two). If anyone has a recommended place to get one for a good price (or with cheap/free shipping!!!), feel free to speak up. It hurts to pay $7 to ship an $8 part. I guess it's just the principle ot it...