I have a Rheem RGFD that was just installed this past summer, so this is my first heating season with it. So far, so good...nice, even temp distribution, hardly any noise, I'm almost not even aware of the furnace running. So different from what was here before...I just LOVE this new system.
Anyway...where was I? Oh, yeah, my question: When my touch-screen stat clicks on, it sometimes says "System On +2". This is usually when I crank the temp setting up from, say 62 to 70. Is this the stat's way of telling me that it's running in high fire? I can't seem to find any difference in the look of the flame (through the observation window on the furnace) and except for the first few minutes of operation, there's not much difference in the sound level.
Once the room temp has stabilized, the subsequent cycles have just "System On" showing (without the +2). I presume this means that it's at low-fire. As the cycle progresses, the noise level and airflow taper off very gradually, which I guess indicates that the mod feature is functioning properly. Correct?