[prairieschooner]

OK the NT-16L is a 16,000 BTU input / 12,000 BTU output, while the NT-12L is 12,000/9,000. We have the NT16L and I would expect you to have the NT-16L, there is a model/serial tag on the unit although you may need to pull it to get those numbers. These units are Suburban Dynatrail models. The L may be a designation for LPG since they are designed for Propane (LPG) but I am not sure about that at all.
I replaced the Fan motor on one of mine last year. The old Number for the Fan Motor was #220634 but cross referenced to a replacement #2-520950. You should get a replacement "kit" because it has the Gasket needed. Be careful when pulling the Unit because there is a SCREW from the OUTSIDE, otherwise pretty straight forward. Remove the Gas Line, Rear Screw, mounting Fasteners and the wires (2 for the Power and 2 for the Thermostat). I Pulled the Housing on the forward unit but left the Housing in place and slid the unit out that is under the Fridge.
I tried to clean and lube the fan motor but don't bother, it didn't work very long. You may need to be patient with the Squirrel Cage that is inside of the Housing. The Set Screw on mine was stubborn, I had to drill it out to save the Squirrel Cage.
There is a Switch for the NT24-M that tells the unit that it has cooled down. This little switch was only about $20.00 or so and I would recommend that you replace it if you have to pull that unit out as well. I believe that I left that Housing in Place as well.
The reason for leaving the Housings in place if possible is to keep the Ducting in good condition. You may also need some good Duct Tape just because the old stuff would have dried out.
Good Luck.

I forgot to tell you about the burner. I cleaned ours with a stainless steel "toothbrush" size brush. The LPG Gas left behind a residue, no big deal.