Operate the machine with the blind filter in place (doesn't have to be hot) and see what sort of flow you get in the return hose to the reservoir. You can easily operate the machine like this for 30 seconds and then give it a minute's rest.

My thought is that you may get a little flow at first but then it will head to essentially some drips. This would be indicative of a sticking/stuck suction check valve internal to the pump.

This problem has, in fact, been reported before and I tried a search with no luck.

edit - but now that I have been given superb assistance by the chief detective - here ya go - Pump? OPV? Check Valves? Wit's end!

Yes, the pump was toast but all is well...read my tale of happiness below:


All's good in espresso land...

For the past several, probably 6 months or more, I've been having serious trouble with channeling in all of my espresso pulls on my Andreja premium. I tried the NSEW, the toothpick, combined the two, standing on my head while whispering sweet nothings to the portafilter - nothing worked. Occasionally I'd get something that was ok, but rarely twice in a row.

So, I decided that it must be the grinder. It was most likely operator error, but after 6 years with my Rock doser it was time for a change anyhow. So I narrowed it down between the K3 and the Baratza Vario, and after reading many reviews decided on the Vario. It didn't look like much, but performance is what I was after. So, a couple of Friday's ago I called Chris Coffee and ordered it up. I had considered ordering a new pump for my Andreja at the same time, but thought maybe it really was the grinder?

The next morning I descaled my machine, and the pump died. But I had to wait until Monday to order a new one, which wouldn't get to me until the day after the Vario. Then, to top it off, I was out of town when they both arrived, and couldn't get to them until this past Saturday. So I tore apart the machine and replaced the pump, cleaned out the lines inside the machine, replaced the expansion valve seat and the cam lever gaskets while I was at it. I then let it warm up and began the dialing in process. Right away I could tell something was better with the machine - the water dispersion without the portafilter was much better, and sure enough, so too was it when pulling a shot. I was pumped.

I had to adjust the burrs per the instructions in the manual, but the provided tool made it very easy. And it only took about ½ lb of coffee to get it dialed in, and get my 25 second pull with my triple basket. It looked and tasted beautiful. As for the Vario, it's fantastic. No clumping, no waste, hardly any mess. Some people say its quieter, and it is quieter than the Virtuoso I have, but grinding coffee is a noisy affair. The grinds are very fluffy - so much so that I might need some more coffee in the basket. I probably should use a scale, but I don't have one.

I guess the point of the story is that I have a great espresso experience again, but I'm not sure what made the difference. I can honestly say I don't really care that much, but I do love the new grinder.