What clogged my Grainfather pump?

[pym99]

My Grainfather pump (more accurately, the pump filter/screen below) got clogged while pumping to the fermenter for the first time since I got a hop spider. The recipe was a bit different than my usual because it included spelt and oat malt, which I milled mixed in with my regular malt at the regular setting. The other difference was that I used whole hops instead of pellets, in the hop spider as usual. The pump stopped pumping wort out with an inch or two above the pump filter, leaving a liter or so more in the Grainfather than usual.

Any ideas which ingredient caused the clogging, and what I can do about it in the future?

Thanks!

- I had already rinsed and started to clean it before I took the photos; it was completely clogged

 

[Jag75]

If you had a really fine crush that stuff seems to find it's way around the malt pipe since the top and bottom screen doesnt fit snug around the pipe . Also when using wheat or oats I use rice hulls to help . Around half a pound for a 5 gallon batch. Also I bet your ball and spring valve was clogged as well. I've had to take mine apart to clean the gunk out to allow it to flow. To me it looks like grain was the culprit not hops.