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Suburban NT Furnaces
Suburban NT Furnace


Starting At: $625.73

Product Code: VTS-423

NT34SP [Add $24.97]
NT40 [Add $115.43]


The ducted Suburban NT Series propane gas furnaces were used in Airstreams and other vintage trailers from the 1970s and later. The styles have changed somewhat, but they are generally the same size and shape as the originals, making them the proper replacement furnace for older NT units of a similar BTU rating.

Cabinet size is the same on all models, providing a standardized size with three capacity options (see below). NT Series furnaces are not difficult to install, but some of the internal hot air ducts and gas line locations are slightly different than the original. Using flexible pipe and ducting, you can make the connections to your old system. See below for helpful documents.

All three NT models have two 4" round ducts on the left side and two more on the right side. They also have one rectangular duct on the bottom. When you receive the furnace, either 3 or 4 side ducts will be open (see ducting specs below) and the bottom duct will be closed.

To use the bottom duct, you must close the side ducts and use a duct adapter for the bottom. These parts must be purchased separately. If you are using side ducts, you will need the round duct collars.

All units include:

  • Gasket-sealed vent assemblies.
  • Energy-saving and low maintenance solid state electronic ignition.
  • Long lasting steel gas manifolds for a long life.
  • Efficient sealed forced-draft combustion.
  • Durable chrome-plated vent caps.
  • Operable from wall thermostat (but thermostat not included).
  • Unit Size: 12 1/2" H x 12" W x 23" D

Minimum ducting:

  • NT-30SP requires a minimum of 36 square inches of duct coming off the furnace.
  • NT-34SP and NT40 require a minimum of 48 square inches coming off the furnace.
  • When you receive the NT-30SP you will see that 3 of the 4 round ducts are open and the bottom rectangular duct is closed. This is the minimum ducting required. Or you can close the round ducts and duct solely from the bottom rectangular duct.
  • When you receive the NT-34SP or NT40, you will see that all 4 of the round ducts are open and the bottom is closed. This is the minimum ducting required. Or you can close the sides and use the bottom rectangle.
  • Don't forget to buy the accessories necessary to do proper ducting. Round duct covers, round duct collars, and the bottom rectangle duct adapter are sold separately.

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