Hydro Flame Furnace 82-series fan doesn't always shut off! Blows cold air!

[aaron7]

Can't find the model number on my furnace but the manual says 82-series.

It'll click on with the thermostat fine and runs fine but when it hits temp and is supposed to shut off it'll only shut off the heat and the fan will keep blowing till you shut the power switch on the t-stat off.

It doesn't do this every time; sometimes will run, blow heat, get to temp, and shut off properly.

It had the original analog thermostat and I installed a digital Honeywell one with the same issue.

Thoughts?