LD1
Epic Contributor
I need a new t-stat, and has to have a specific feature, and hoping someone could point me in the right direction.
I am trying to work out some minor nuisances with my geothermal system. This is my first winter on the unit.
The furnace is a 4-ton, 2-stage unit, with (4) 800' ground loops (about 100gal capacity)
The combination of outside temps and loop temps the last few days, I have been having some extended run times. Heat sing is 0.5 degrees right now, so it should come on 1/2 degree below where I have it set, and shut off 1/2 degree above. It is set at 71. Just this past run cycle, it actually came on at 70.2 and off at 72.4. So I am getting a bit more swing than I have it set for. But thats not the issue. To gain that "actual" 2.2 degrees, the unit ran on first stage for 1 hour and 13 minutes. ITs 34f outside right now, and those run times were longer this morning.
With the extended run times, got me thinking. In theory, the unit could run on first stage 24/7 and never shut off, and never reach setpoint. If the heat it makes on first stage is exactly equal to heat loss from the house.....the temp would remain constant, never gaining enough to shut off, nor loosing enough to kick on second stage. And even if it did loose enough to go to second stage, as soon as it warmed enough to drop second stage and run only first again, it would fall behind and go to second stage again.....a never ending cycle that would cause the unit to run 24/7 until outside temp warmed up.
Fortunately, there is a setting in my current t-stat to prevent the later from happening. Its called "satisfy setpoint". In which if it falls far enough behind on 1st stage to kick the 2nd one on.....the second one remains on till the setpoint is met and the unit as a whole will shut off.
But there is no setting to prevent the first scenario from happening, in which the unit could run on 1st stage neither gaining nor loosing ground, and never shut off.
The t-stat in my parents house is not this way. It has a setting, in which after a set time (15 min, 30 min, etc) that the first stage dont reach the setpoint, it automatically goes to 2nd stage. Not sure the model of their t-stat, but wouldnt do me any good anyway as theirs is wired and I need a wireless.
So who out there knows of a wireless t-stat that can confirm that it has that feature. That it will automatically go to second stage or backup heat if the setpoint isnt reached in a timely manner on the first stage?
I am trying to work out some minor nuisances with my geothermal system. This is my first winter on the unit.
The furnace is a 4-ton, 2-stage unit, with (4) 800' ground loops (about 100gal capacity)
The combination of outside temps and loop temps the last few days, I have been having some extended run times. Heat sing is 0.5 degrees right now, so it should come on 1/2 degree below where I have it set, and shut off 1/2 degree above. It is set at 71. Just this past run cycle, it actually came on at 70.2 and off at 72.4. So I am getting a bit more swing than I have it set for. But thats not the issue. To gain that "actual" 2.2 degrees, the unit ran on first stage for 1 hour and 13 minutes. ITs 34f outside right now, and those run times were longer this morning.
With the extended run times, got me thinking. In theory, the unit could run on first stage 24/7 and never shut off, and never reach setpoint. If the heat it makes on first stage is exactly equal to heat loss from the house.....the temp would remain constant, never gaining enough to shut off, nor loosing enough to kick on second stage. And even if it did loose enough to go to second stage, as soon as it warmed enough to drop second stage and run only first again, it would fall behind and go to second stage again.....a never ending cycle that would cause the unit to run 24/7 until outside temp warmed up.
Fortunately, there is a setting in my current t-stat to prevent the later from happening. Its called "satisfy setpoint". In which if it falls far enough behind on 1st stage to kick the 2nd one on.....the second one remains on till the setpoint is met and the unit as a whole will shut off.
But there is no setting to prevent the first scenario from happening, in which the unit could run on 1st stage neither gaining nor loosing ground, and never shut off.
The t-stat in my parents house is not this way. It has a setting, in which after a set time (15 min, 30 min, etc) that the first stage dont reach the setpoint, it automatically goes to 2nd stage. Not sure the model of their t-stat, but wouldnt do me any good anyway as theirs is wired and I need a wireless.
So who out there knows of a wireless t-stat that can confirm that it has that feature. That it will automatically go to second stage or backup heat if the setpoint isnt reached in a timely manner on the first stage?
