Better heat with a blow dryer?

[Sunnyside]

We went out to the Mountaineer to get it ready to pull to the campground where we winter camp, and I turned the heat on so the DW didn't get frostbite (8 deg outside). The furnace ran for a while and shut down. When I re-started it, it seemed to work, but had very little air/heat coming from any of the registers. Less than a regular blow dryer. This does not seem normal to me. Any ideas?

Thanks,

Jim