Question about my A/C Thermostat

[aphex]

Why does my thermostat register one temperature, but when I pull it off the wall and simply place it on the counter does the temperature change dramatically?

I understand the sensor is in a protected place on the backside of the thermostat, but it reacts opposite to how I would think it should.

For instance, when it was on the wall, the thermostat was showing 74 degrees. I pulled it off and placed on on the counter directly below (less than 3 feet away), and it shot up to 82 degrees.

Is there something wrong here?

 

[Baked]

Because the exposed counter surface is colder than the insulated wall?

 

[aphex]

Originally posted by: Baked
Because the exposed counter surface is colder than the insulated wall?

But isn't that the opposite of what it should show? The temp shows its colder on the wall than the counter surface, though technically im balancing it on its bottom, so its not touching anything, just the ambient air.

 

[olds]

Originally posted by: aphex
Why does my thermostat register one temperature, but when I pull it off the wall and simply place it on the counter does the temperature change dramatically?

I understand the sensor is in a protected place on the backside of the thermostat, but it reacts opposite to how I would think it should.

For instance, when it was on the wall, the thermostat was showing 74 degrees. I pulled it off and placed on on the counter directly below (less than 3 feet away), and it shot up to 82 degrees.

Is there something wrong here?

You're smoking too much pot?

 

[Capt Caveman]

Is it digital or one of those older mechanical ones?

 

[aphex]

Originally posted by: Capt Caveman
Is it digital or one of those older mechanical ones?

Digital

 

[Squisher]

If this is a digital thermostat it is possible the voltage supplied by the battery as opposed to that supplied by the transformer is causing the readout to change. The battery is there just so you can sit down in a comfortable chair and program it and also there so that the program isn't lost during power outages, not to give a reliable readout when off the wall.

 

[drinkmorejava]

The countertop will feel colder to the skin because it can transfer heat faster, however, it should be about the same temperature. I'd say it's because of the battery vs transformer.

 

[aphex]

Originally posted by: Squisher
If this is a digital thermostat it is possible the voltage supplied by the battery as opposed to that supplied by the transformer is causing the readout to change. The battery is there just so you can sit down in a comfortable chair and program it and also there so that the program isn't lost during power outages, not to give a reliable readout when off the wall.

Ahhhh, ok makes sense then. Thanks!

 

[Rubycon]

How long did it take you to remove it? If the sensor has a small mass it's possible that your body temperature could warm the sensor giving a false reading temporarily. The refresh rate is probably quite slow. Let it sit there for a while and see if the temperature drops back down to normal.

I'm not sure how these digital 'stats handle anticipation (aneroid mechanicals used a carbon resistor for cooling and wirewound rheostats - adjustable - for heating anticipators). So if anything the reading should be slightly lower when dismounted.