We keep two-pole, 40-amp 24v coil contactors on all of our vans. They are versatile and reliable, and you can replace most residential A/C contactors with them. There are a few things to watch for, though, especially when you have a crankcase heater. Many brands power the crankcase heater constantly and shut it on and […]

This is a VERY in-depth look at ACFM vs. SCFM and why it matters to airflow measurement from Steven Mazzoni. Thanks, Steve! Imagine your job is to figure out how fast baseballs were traveling before they hit a sheet-rock wall. The only method you have is to measure the depth of the dent left in […]

Jacques Charles was a French physicist (and a real looker based on that photo) born in 1746. Little is known about his educational and family background, but he began his career as a clerk at the Ministry of Finance in Paris. After a short time as a financial clerk, he began focusing on science. The […]