Hi John and Pat,
While your unit may not be outputting what it should, just wanted to let you know that the fireplace is not designed for or intended to heat the trailer. It certainly can be supplemental however.
If you suspect that the unit is under-performing, my suggestion is that you contact your dealer and ask them to test it to the manufacturer's rated output. If it comes back as a fail, then the fireplace manufacturer should stand behind the warranty on it.
Jim