The 2720sl uses the nt20se furnace which has no ducts so the output side should be ok. I don't know how these get their cold air return. Take a look at how big the openings are for air to get into the furnace area.
The other difference in the nt20se is that the limit switch has a 170 degree setting rather than 180 degrees for the nt20s used in the 2720sd.
If your furnace is attempting to heat the trailer and the output temperature goes up 170 degrees and then drops to 100 degrees or so before cycling back to 170 degrees then back to 100 etc etc. it is cycling on the limit switch. You will hear clicking sounds as this occurs. This has nothing to do with the thermostat which keeps telling the furnace to make heat until the set temperature is reached. This cycling burns battery power because the fan keeps running all the time and it takes longer for the furnace to heat the room. In the case of a severely choked system such as I had the furnace could not heat the TM from 32 to 72 degrees. It made it to about 50 degrees and just cycled away making no more progress.
Peter
|