I have been having difficulty finding someone that can give me the proper information on this, hoping to find someone here that can help.

I have a Trane XL80 furnace (U060R936K) and as I was verifying the operation of the heating stages (did not have 2 stage tstat) when I noticed that once the tstat kicked the 2nd stage off the blower turned down to low speed for 1st stage heating right away.

According to the installation manual and process of the logic, once the 2nd stage is satisfied the tstat will open the relay at that time the draft blower slows and 2nd stage gas shuts off. The blower then should run at high speed for approximately 30 seconds. My concern is the blower shuts off as soon as the command goes away for the 2nd stage. I am not sure if this is normal, maybe because the 2nd stage only ran 5 minutes and was not hot enough to constitute a longer run time.

I am going to be doing some flow checks today with a hood so I need to let the system run longer. I will see if it does the same thing or will run longer since it will be hotter. Any feedback would be greatly appreciated.