The Ultimaker filament loading process has three phases--a slow loading, a fast loading, and then a second slow loading to get the filament the last part of the way down the tube and into the nozzle. The photos below are of the feeder and printhead on the Ultimaker 2+ and Ultimaker 2+ Extended; however, these instructions apply to: the Ultimaker 2, 2+, 2 Extended, 2+ Extended, and 2Go.
1. You can either load the material during the material loading in the start up wizard, or by going to Maintenance --> Advanced --> Insert Material. In either case, when the nozzle is hot and the material is ready to insert, you’ll hear the feeder motor start to turn slowly. On the 2+ feeders you'll see the silver colored circle on the back of the feeder begin to turn. On the UM2 feeders, you'll see the silver colored knurled feeder sleeve protruding from the black feeder housing turning.
2. Push the filament firmly up through the hole at the bottom of the feeder. The hole is recognizable by the metal grommet at the bottom on both the UM2 and UM2+. (Note: if your UM2 is more than 1 year old as of 3/22/16, there may be no metal grommet, just a hole.)
3. You should be able to feel it when the filament is caught by the feeder, and you’ll see the lever inside the feeder move itself to the left slightly (red arrow), to make room for the filament. On the UM2 machines, you'll also see the white lever with the bearing adjust slightly.
The ideal place to begin the fast forward is just as the filament comes over the feeder housing (green arrow) in the back of the machine. If you wait too long, the filament will grind at the feeder when it reaches the nozzle. You trigger the fast forward by pressing the button on the front of the machine and choosing Continue. The motor will make a whooshing sound as it turns quickly for a few seconds.
4. At the end of the fast loading with the Ultimaker 2+ machines, the filament disappears into the printhead block, but should not be coming out of the nozzle yet. After fifteen to thirty seconds of additional slow loading, the filament should begin to come out of the nozzle. When you see it, hit Continue to move on and choose a file from your SD card and print. With the UM2+, if the filament stops moving in the tube, wiggle the tube in a circle where it meets the print block.
With the Ultimaker 2 (not +) family of machine, the filament should come to just above the printhead block. It will then advance slowly through the rest of the printhead and down toward the nozzle. You'll be able to see it in the tube as it makes it's way past the spring on the printhead. If you begin to hear a clicking sound, but no filament is coming out, push up on the filament from the back of the feeder; it may be caught on the edge of the PTFE coupler and just need a little help. It should begin extruding.