I know that the differences in these modes have been discussed at great length and are well understood. However, I think I noticed something that I was not previously aware of before by placing a digital thermometer right near the stove temp sensor. (If this is not news, I apologize but I did do a forum search first.)
With outside temps around 15 here, I figured that the auto/manual switch, while in room temp mode, would have little effect since the stove would not be likely to go out at any point. There does seem to be a difference in the control strategy though. In room temp/manual, The stove appears to run at full output up to approx. 1.5 to 2 degrees above setpoint. Setpoint is a relative term because my Accentra has a knob and it's not very accurate to the increments printed around it. But for sake of argument, with a setpoint of 71.5, the stove runs with a large fire up to about 73-73.5 degrees. At that point, the stove goes into a low burn mode until the temp drops to about 1 to 1.5 degrees below setpoint (about 70-70.5). This cycle repeats resulting in a 2.5 to 3.5 degree swing (hysteresis).
If I stay in room temp mode but switch to auto, I observe that the stove constantly varies the fire size in order to hold room temp as steady as possible. Since switching about 2 hours ago, the room temp at the digital thermometer has only varied by a few tenths of a degree from the setpoint of 71.5 (70.9-71.6).
I don't know what this means for efficiency and pellet consumption but I found it interesting and I may do some more experimentation using a temperature datalogger that I have. I'll post some graphs if they appear useful.
With outside temps around 15 here, I figured that the auto/manual switch, while in room temp mode, would have little effect since the stove would not be likely to go out at any point. There does seem to be a difference in the control strategy though. In room temp/manual, The stove appears to run at full output up to approx. 1.5 to 2 degrees above setpoint. Setpoint is a relative term because my Accentra has a knob and it's not very accurate to the increments printed around it. But for sake of argument, with a setpoint of 71.5, the stove runs with a large fire up to about 73-73.5 degrees. At that point, the stove goes into a low burn mode until the temp drops to about 1 to 1.5 degrees below setpoint (about 70-70.5). This cycle repeats resulting in a 2.5 to 3.5 degree swing (hysteresis).
If I stay in room temp mode but switch to auto, I observe that the stove constantly varies the fire size in order to hold room temp as steady as possible. Since switching about 2 hours ago, the room temp at the digital thermometer has only varied by a few tenths of a degree from the setpoint of 71.5 (70.9-71.6).
I don't know what this means for efficiency and pellet consumption but I found it interesting and I may do some more experimentation using a temperature datalogger that I have. I'll post some graphs if they appear useful.
