Endlessly pushing the ignitor button

Question

When hooking up a new 20 lb propane tank to the heater, it must take 4-5 minutes and almost endless pushing of the ignitor before the pilot light will ignite and stay on. I was told by the previous owner that it takes so long to get "the air out of the line". My other problem is fear of "wearing out" the ignitor prematurely.
Thanks in advance/steelie