I've been using a racking cane for years but picked up one of these recently because that was all they had at the store. Is there a trick to getting it to work when you only have a half batch, say 3 gallons? The liquid falls back down into the autosiphon into the carboy rather than down into my bottle bucket. Not enough of it clears the crook in the cane to travel down the tube and do the work need to start the flow. This was one of my frustrations when I first used autosiphons years ago and it has come back to haunt me.
They can be a bit tricky at times. Try taking the cane out of the tube and running hot water over the plunger for a few minutes. Then reassemble lube it up good with starsan. Make sure your hose is tight at the top of the cane and there is no air leaks. It may take a few rapid pumps (full stroke) (waiting for the comments on that phrase lol). I recommend you try this with some water in a similar vessel first. Good luck!
The issue isn't air leaks. I only have this problem if I have a small batch. I think it is because I need to get the initial flow about 1.5 feet higher than if I have a full batch (more work). I do have difficulty with the full stroke because of ceiling clearance issues (I bottle in my cellar). I gave up and rigged up a racking cane.
I typically use a short and vigorous motion to get my auto pump running There's a little oxidation in this method, but when DON'T you oxidize a little when racking?
I can get a siphon going on my auto siphon with less than a gallon of wort in the fermenter so it's definitely possible. The only thing I can think of (if you are sure you have no leaks) is maybe try doing a few "short pumps" in rapid succession at first. Edit: looks like inchrisin made the same recommendation a minute ago while I was typing my response!
