Can a Chinese Diesel Heater run without fuel pump? [Re-upload due to sound problems]

Since the clicking piston pump is annoying to me, I'm testing, if a Diesel Heater like Eberspächer, Webasto or Planar can also run without a pump, just on gravity. See yourself, if it works. [Sorry for the sound problems with the original video. Somehow the renderer didn't like a specific frame.]