Those of you that still have a vintage Sportsmobile van Circa 1990s-2000 with the penthouse. I have a 1995 Dodge B3500 with a suburban NT12-Se propane heater. I go many cold places and researched getting a larger hear to help. what I found was a new heater was $500+ My research showed that There is virtually no difference between the NT12 and the larger NT20SE. The 12 is 12,000BTUs and the 20 is 19,000btus. All of the parts are interchangeable except for the orifice which is larger for the bigger heater. $7 for the orifice here,
https://pdxrvwholesale.com/products/...orifice-180231.
While I was at it I changed the fan from the SE series to the SEQ which is a more modern design and runs quieter here.
https://pdxrvwholesale.com/products/...mpeller-350207.
As a result I was able to do the upgrade for less than $30 and My heater puts out much more heat and runs for shorter times because of the upgrade. It is also quieter. Both parts install easily for the average do it yourself-er and are a direct fit on the motor and burner.