Mine is mounted vertically in a skygate hawk. Yesterday I noticed bubbles going into the pump when I throttled UP. There was not a single bubble coming INTO the ACCU from the on board fuel tanks, but several bubbles going up into the pump from the center feed line of the ACCU.
I have not followed the above mentioned purging procedure. I simply fueled up using the fuel line and started. If we drain out a bit from the "fill lines" wont air go into the ACCU when you remove the tube to cap it off? I dont understand why this is a must as other bubble busters dont need this method of purging. Is the ACCU designed differently that it needs a reverse flow through the main tanks and the fill line? Is it mentioned in the instruction sheet?