Notice the corrosion on the filling port. Not present in all the other EPGs . Also ,in the second image, notice the corrosion at the juncture of at the plastic pump port and and the copper pipe. This is clearly not due to soldering. tThis corrosion may be due to the suspending agents such as oleic or stearic acids in the ferrofluid. The corrosion pattern near the filling port is consistant with a spill or overflow and seems correct given the position of a working epg. The appearance of the smaller corrosion of the plastic-copper junction is consistant with a slight seepage or leak.
little giant pump photo courtesy rwg research
http://www.youtube.com/watch?v=0OT--OXQ-aY
