Hmmm, I had no idea that was the recommended procedure for operating the Suburban furnace. I've used mine for almost two years and have never followed that protocol. When I turn it on it blows cold for a bit until the furnace burner kicks on. And when I shut it off, it blows cold for a few minutes after the burner goes off. On some trips to Mammoth, I've run it 2-4x a day for 1-2 hours each time. Always works just fine and a tank of propane lasts a LONG time.
2006 SMB 4x4, EB-51, 6.0psd