Suburban NT12SE Furnace Upgrade

[pcdarks]

I have a 1995 dodge Sportsmobile Van. It has a Suburban 12,000 BTU heater in it now, model NT12SE. I travel in cold climates and have been looking to upgrade to a 19,000 BTU heater that is the same model,NT20SE. Doing some research I have found that the only difference in the two heaters is the Orifice size in the burner. Burner, gas valve, fan, housing, clearances, exhaust ports are all the same part number. To buy a larger heater is around $500 but I bought the larger orifice for $6. Anyone else use this modification?

[Clarkboulder]

@pcdarks
I have recently looked into this as well. I spoke yesterday with Suburban CS. I've been having problems with my 96' NT12SE at altitude only intermittently working when everything else checks out OK. Suburban only tests their models to 4500ft. Recently someone else told me that the larger aftermarket orifice swap would help with the high altitude function but was actually dangerous if used at lower altitudes as it would burn rich and could turn the Van into a fireball. (Obviously high and low is relative. I live at about 6Kft and often camp between 4500-10,500ft. So low to me is the 6000 and below since it's my baseline.) So I am left to wonder the question. The module ignition board part #s are all the same between 12,16,20. I think the 16SEQ would be plenty increased warmth being 16KBTU over 12K. The SEQ is a quieter blower version of the SE. A quieter blower would be nice and worth the extra money but maybe not $500worth. But I am very reluctant to install a larger orifice if it will make me explode in the night. :-)

[Clarkboulder]

Where did you source the larger orifice from? Part number? Have you yet tried this?

[arctictraveller]

Originally Posted by Clarkboulder

@pcdarks
Recently someone else told me that the larger aftermarket orifice swap would help with the high altitude function but was actually dangerous if used at lower altitudes as it would burn rich and could turn the Van into a fireball. :-)

It seems to me that at altitude, you would want a smaller orifice due the lower amount of oxygen available, but then, I have heard of folks who cover the air intake during start up at altitude, just long enough to get it to light, but that would cause a richer mixture. I'm confused................

[pcdarks]

NT20SE orifice here. https://pdxrvwholesale.com/products/...orifice-180231
SEQ fan Here: https://pdxrvwholesale.com/products/...mpeller-350207


On this same site you can call up all of the parts for the 12,16 and 20 heaters. If you examine the parts lists from all of the different heaters you will find that the only difference is the motor on early models and the limit switch which is a 170 degree for the 12 and 16 and 175 for the 20. If all of the part numbers are the same it's pretty much a no brainer. I went out last week on a mid 20s night and My heater worked great. Also I live at 7000 ft. Less than $40 for the upgrade vs buy a 20 for $600+.P.S. the SEQ fan is a direct fit and actually lulls me to sleep.

[pcdarks]

Originally Posted by Clarkboulder

@pcdarks
I have recently looked into this as well. I spoke yesterday with Suburban CS. I've been having problems with my 96' NT12SE at altitude only intermittently working when everything else checks out OK. Suburban only tests their models to 4500ft. Recently someone else told me that the larger aftermarket orifice swap would help with the high altitude function but was actually dangerous if used at lower altitudes as it would burn rich and could turn the Van into a fireball. (Obviously high and low is relative. I live at about 6Kft and often camp between 4500-10,500ft. So low to me is the 6000 and below since it's my baseline.) So I am left to wonder the question. The module ignition board part #s are all the same between 12,16,20. I think the 16SEQ would be plenty increased warmth being 16KBTU over 12K. The SEQ is a quieter blower version of the SE. A quieter blower would be nice and worth the extra money but maybe not $500worth. But I am very reluctant to install a larger orifice if it will make me explode in the night. :-)

The less oxygen at altitude will burn richer.(less oxygen more fuel= richer mixture) Lower altitude make the unit run leaner. Standard fuel theory.

[pcdarks]

On an additional note, I checked the temperature output of the 12 heater and then the same heater with a 20 orifice with an infrared thermal sensor. Yes the 20 puts out higher heat as you would expect but still far below dangerous temps. I did notice it really dried my Fly fishing shoes much better over the night.

[pcdarks]

https://www.sportsmobileforum.com/fo...ter-30823.html

[Stone Cite]

Originally Posted by pcdarks

On an additional note, I checked the temperature output of the 12 heater and then the same heater with a 20 orifice with an infrared thermal sensor. Yes the 20 puts out higher heat as you would expect but still far below dangerous temps. I did notice it really dried my Fly fishing shoes much better over the night.

Excellent info. Thanks!