Instruction: Given a question and its related document, determine if the question is answerable by analyzing the information in the document. Output yes if the document addresses the question, or no otherwise.

Input:
Question: Will the probes provided with this unit measure ambient air temperature, or do they have to be in contact with a surface to give accurate readings?
Document: I could not calibrate this error out, since there is no gain adjustment on the instrument. I then pressed the T1-T2 button. The unit said the temperature difference between T1 and T2 was 100F! (not 10F). Loose probes? No. Apparently the unit could not reliably subtract with the probes at about 199F.
I asked Amazon for a refund and I did not attempt to get a second unit to see if it had the same issues. That said, the unit I received malfunctioned in a way that made me believe the design suffers from poor quality.New out of the box, I installed a new alkaline battery and I put the supplied temperature probes in a cup of stabilized ice water per the calibration instructions. The probes read 2-3 degrees F apart.
I had previously order a cheap electronic thermometer for adjusting HVAC Freon levels and came to deeply regret it. Never got the same readings twice and never knew if the Freon was too much or too little.I've had none of those problems with this unit.
So far so good. The calibration instructions end there...Having had my share of bad experiences with instrumentation, I went one step further and that's where everything went awry. At my altitude deionized water boils at approximately 199F. To confirm that the instrument was accurate over the range at which I will use it, I put both probes in a bath of simmering deionized water.
However, the erroneous readings on the Fluke 52 were such that it was possible for me to associate the error with the source of the problem. Of course, the Fluke 52 costs three times as much as the Fieldpiece.If I could give the Fieldpiece a revised rating of "n/a" so as not to affect their average score, I would. As I said, the poor results I observed were not the fault of their instrument.
The temperature meter is easy to use and calibrate. It seems like a well made meter and it takes less than a minute to determine the accurate temperature once the hvac system has stabilized. I have used it about 30 times and so far I am very pleased with it.
I bought this thermometer a few years ago when my FLUKE 52 thermometer broke after 12 good  years of service. Usually I always go for Fluke but the cost of the model 52 thermometer has just gotten way too expensive. I simply don't know why a meter that only measures temperature has to cost over two hundred dollars. I can say this meter is rugged , reliable and accurate.
I purchased this item for general HVAC use and it appears to be a decent  value. Quality is good & unit is capable of the basic functions (i.e., dual-thermocouple inputs; Min/Max temperature sampling; temp. hold; 1 deg/0.1 deg. resolution). I calibrated unit using the two thermocouples included and it holds calibration OK. I later purchased two additional probe-type thermocouples. They matched within 0.2 deg.
I just use the meter to measure delta t's on minisplit heat pumps. comparable equipment sells for $250 - $300. I am very pleased.
I like the fact that this meter can be calibrated. It costs about 1/3 the the price of the Fluke model.The two inputs make it great for checking super heat and sub cooling. And it's good for taking air temp in duct work and checking air temp from room to room in a customers house to prove that the master bedroom is not 10 degrees warmer than the living room.Bottom line is YES it is a good quality meter.
Answer: yes