Goodman Furnace F02: Blower Speed Number, Not an Error

Where F01 to F09 appear in Goodman's menus

Each blower mode has its own menu item, and choosing it shows the current speed as F followed by two digits. The rows below are the blower-speed items from each manual's menu table, as printed; the other items in those menus are settings and history, covered further down.

The speed-selection steps say the same thing in prose. The *M9S96: "Press the left or right switch until LED displays “FSd”. Press the center switch and LED will display the selected speed number as Fxx (xx: Blower speed number from 1 to 9). F01 is the default speed for circulation." (IOG-2029A p. 35). The *M9S80*U: "Press option button and LED will display the currently selected speed number as Fxx (xx: Blower speed number from 1 to 9)." (IOG-2031A p. 22)

Which speed is the default

Defaults differ by series and by mode, which is one reason the same F number does not mean the same airflow everywhere. Goodman's tables mark the default speed for each thermostat call.

So on a single-stage *M9S96, F02 is the speed the control uses for heating unless someone has changed it. The *M9S96 note on the same page reads: "NOTE: Always refer to the Heating Chart to choose from available heating speeds".

What F02 means in airflow

An F number is an index into a model-specific airflow table, not a fixed amount of air. Each of these manuals has tables that list the airflow, in CFM, for F01 to F09 at a range of external static pressures, separately for each cabinet size. Those tables are on pp. 35–38 of IOG-2027B ("Airflow Table GM9C96" and "GC9C96"), pp. 45–50 of IOG-2029A ("Airflow Tables" for the *C9S96, *M9S92 and *M9S96), and pp. 30–31 of IOG-2031A.

Picking a speed is an installer's job. The *M9S80*U wiring diagram says so in note 3: "BLOWER SPEEDS SHOULD BE ADJUSTED BY INSTALLER TO MATCH THE INSTALLATION REQUIREMENTS SO AS TO PROVIDE THE CORRECT HEATING TEMPRATURE RISE AND THE CORRECT COOLING CFM." (IOG-2031A p. 32) The same manual adds: "The selected speed must provide a temperature rise within the rise range listed with the particular model." (p. 22)

How to find the real fault code

Faults on these furnaces are not F codes. Two items in the same menus are where the control reports them, and both show the code as E followed by two characters.

The codes that show up there, such as EE2 or E11, are explained series by series on the Goodman furnace codes hub, and the pressure-switch codes have their own page. The idle reading, 1dL, and the gas-heat status, 9H, are not faults either.

Goodman's safety wording

Blower settings are made at the furnace's control board, among the gas and electrical parts of the appliance. Goodman prints its gas-leak instruction on p. 3 of IOG-2029A, IOG-2027B and IOG-2031A; it is here verbatim with the carbon monoxide warning.