If the terminal board on the furnace has wires hooked up to R, W, Y, G then buy a single stage type of tstat. If it has an W1 and W2 terminal with wires on them then you need a 2 stage tstat. Label the wires before removing any of them. There should be a wiring diagram of the unit on the inside of one of the furnace doors. Hi All! I have a 2,300 sq. ft. two story home with an Armstrong Air ULTRA 5 TECH 80, (Model No. 45647-001) furnace heating it. My wife and I think this furnace was in our house before the previous occupants added a large addition and that it under-powered to handle the size of the home. I have done some searching on the web regarding this Air Ease Ultra SX 80 Natural Gas hot air Furnace. Armstrong air ultra sx 80 manual. Armstrong air ease furnace manual ultra 80 sx free PDF ebook downloads. eBooks Manuals armstrong ultra sx 80 furnace starts up and runs and then the gas shuts off for a Parts Located In The Air Handler Section (Indoor Unit) For parts located in the condensing unit (Outdoor Unit) Click Here All MODELS: Search for your part below using your model number or part number. If you cannot locate your part using the above part finder Call or Text Message 1-914-294-2432 (EST) or 1-281-817-1088 (CST) or 1-509-293-9290 (PST) Gas Furnaces Product List List Current as of January 02, 2009 Armstrong Air Ultra V Advantage 93 Gas 92.5 All models beginning with G1D93 Armstrong Air Ultra V. There's a perfect choice for you. The Armstrong Air product family includes a smart, efficient solution for every home. Find your Ideal System ». Furnaces Product List. ROTOM MOTORS FB-RFB547 | Armstrong Johnson Air ease Efficiency Ultra 90 Draft Inducer 115 Volts. 4.8 out of 5 stars 7. $125.50 $ 125. 50. Get it Wed, Jun 22 - Mon, Jun 27. OEM Upgraded Replacement for Goodman Furnace Vent Air Pressure Switch B13701-42. 4.5 out of 5 stars 1,258. $17.99 $ 17. 99. Get it as soon as Wed, Jun 22.