This summer, I had a AS Heritage 16 HP (#4A6H6048E1000AA) and AS variable speed air handler (#4TEE3F66A1000AA) installed to replace a GSDX system that had failed beyond reasonable repair. This unit conditions the second floor of my Kansas home. A 3.5ton US Power GSDX continues to condition the main floor and is my benchmark as I've had no trouble with its operation, ecomony or comfort year-round.

The new AS HP cooled our home perfectly all summer but I noticed the fan speed was much faster and never slowed until the last minute or so of the cycle. Now that we are in heating season, I notice the same fan performance but notice that the unit is calling for the electric resistance heat as it recovers from an overnight drop of 4 degrees. Also the air is never warm at the registers like the old GSDX was. Out outdoor temps have been mild, only one night into the teens, the rest in the 20s overnight.

I suspected that the compressor is running in only one stage, even though I understand this is a two stage unit. I checked the thermostat (White-Rogers 1F94-371) and notice there is no wire connected to the Y2 terminal. I stopped my investigation there and called my installer (trusted guy who did all my previous GSDX work). He's due to stop by soon.

Before he arrives, I wanted to get some education on what I should be expecting out of my new system. I learned a lot about my old GSDX and was able to converse with my installer much better that way. I want to have an idea of how this new system should work before he arrives. I've read the installer guides so I know the is specific wiring requirements from the Tstat and also that the fan speeds can be programmed on the control board in the air handler. I suspect the "assistant" installer who did the final day's check out of my new system skipped a step somewhere.

Would appreciate any "education" you guys would consider appropriate! (Promise not to hit my installer in the chops with it when he arrives!)