This topic came up because I was testing out the new MR45 digital recovery machine. That machine goes off by itself when it hits a 20″ Hg vacuum. It's a cool feature, but it is good to know when that level of vacuum is overkill and when it's not enough according to EPA requirements. You […]

I was walking around at the AHR conference today, and I stopped at the booth of a popular hard start kit manufacturer (especially popular with white-shirt sales techs). I listened to the guy behind the booth “training” some municipal maintenance techs on the use of his hard start kit. (To be fair, I actually think […]

Let's start with the basics. Water freezes at 32° Fahrenheit (0° Celsius) at sea level and at atmospheric pressure. When any surface is below that temperature, and the air around it contains moisture, ice/frost will form. In some situations, ice is to be expected, such as in refrigeration evaporators and exposed portions of the refrigeration […]