About 20min into todays' flight and with the transfer pump switches set to auto, the system failed. Actually it had failed before takeoff but I was unaware since the header tank was full on takeoff. I observed the sight gauge level drop to its normal pump on level and kept falling. The EI fuel gauge for the header tank agreed and kept falling. Normally the pumps come on automatically at about 7.5gal but not today so I continued the flight and operated the transfer pumps manually for the 2.5hr flight. About 5 min out from landing I again turned on the transfer pumps manually and this time forgot to shut them off. :-(
Needless to say fuel was being pumped overboard as I taxied into the hangar....

So what went wrong? The auto transfer system is controlled by a solid state relay from Perhelion Design and it works great.
However, the system failed due to the fact that one of the leads to the relay from the buss had somehow slipped off its terminal on the relay(these terminals are pointed down in this installation). A female spade connector that was obviously just loose enough to wiggle itself off, did so. In the end, a simple fix but it reinforces the point that none of our building work should be taken for granted. Now the two power leads to the relay are secured with clear heat shrink as well as lacing tape.

Angier Ames
N4ZQ