I searched for this problem, but couldn't find it, sorry if it is a repeat. I just purchased an 22" Weber Kettle grill and after years of gas grilling am attempting to move back to charcoal. My problem is I have been using a chimney, newspaper and hardwood charcoal, and while it lights and gets red and ashy, it isn't very hot and gets cold quick, like under a half an hour. I fill up the chimney, my vents are open and I put the lid on after I pour them out. The charcoal doesn't even burn all the way through.
You all look like such experts, I just tried the Weber help line and they didn't know how to use a chimney and had never used hardwood. I go to briquettes if that would be better,