Air Conditioning - Outdoor Air Temperature Sensor

Hello,
My condensor has an OAT sensor. What is its purpose?

Is it a heat pump??

Heat pump units use the outdoor air temperature sensor to shut down the heat pump and go to auxilary heat when the outdoor temp drops below a certain set point (usually set at around 35f) most standard heat pump units are inefficient below 35f although some have been designed to produce heat at much lower temps.

Mattison & DNT1,
No its not a heat pump, But I see it on the wiring diagrams. Am I mistaken and its only on the diagram as a option. I did ask the installer (a young man) if there was an outdoor air temperature sensor and he said yes. I assumed I have one and need to know what part of the condensor is it located and does it affect a change of compressor speed? But it appears both of you have answered my question. Its for heat pumps only .....correct?

In the last ten years residential HVAC controls have advanced at light speed you could have a outdoor air temp sensor that serves some purpose besides being on a heat pump but that is the most likely application, what brand and model number unit do you have? it would be interesting to see what and if it is used on this unit. Your electrical schematic could be like the parts diagram for my lawn mower transaxle, it shows axle bearings but they were a option and never installed (yes the axles have worn the soft aluminum casing and it has developed leaks and excessive noise thanks Tecumseh Peerless)

DNT1,
The installed equipment consist of a Bryant 2 speed plus model 598B condensor, a matching evaporator, a Bryant plus 80V varible speed furnace model 315 and a Evolution Control thermostat.

rjordan392

I may be mistaken but this OAT sensor would be used to know the outside temperature from your thermostat. Since you have the high end Evolution control, I would assume the OAT sensor is connected to the control and allows you to call up the outside temp. Just an idea to check on.
:)

Oh yeah you have bought the high end model heck that thing is probably communicating with the gray computers at the sands labratory to control the temp and humidity in your home NICE SYSTEM enjoy.

You guys are soooo funny. Here is what you have. If you click on the "try programming one" and play around some you'll see it displays outdoor air temp. http://www.bryant.com/corp/details/0,,CLI1_DIV42_ETI8788,00.html?SMSESSION=NO

Tigerdunes,
The evolution thermostat does display outdoor temperature. But I believe it should do more. If it does not, then its just a bell and whistle that does nothing to control cooling comfort. If the dealer is telling me straight, that the outside temperature has nothing to do with any of the indoors controls, then why did the manufacturer have it put in (on display) the thermostat? Because I don't change my settings based on outdoor temperatures; I change them when the indoor temperature and humidity feel uncomfortable.

rjordan392

I was just trying to be helpful by answering your question. These high end controls have many "bells and whistles"-some more useful than others. I don't know if this sensor has anything to do with the operation of your system. Many people just like the idea of calling up the outside temp from the thermostat. I suggest you get your manual out and read it from cover to cover and if this does not answer your questions, contact your installing dealer. I looked at the Carrier Infinity system and Evolution controls last year but elected to go with another brand mainly because of lack of confidence in the dealer rather than equipment. I do recall looking at the Evolution Control brochure which was rather involved as far as its primary features and I believe it had an option/interface for connecting to your system via computer-both homeowner and Carrier.

Best Of Luck!

Tigerdunes,
I was referring to the installing dealer as being straight with me. Thanks for your help.