Tech Tips

The amount of pressure you're under depends on where you live. I live in Florida, so I'm very close to sea level. Therefore, the weight of the atmosphere is exerting exactly 14.7 pounds per square inch (PSIA) of pressure on every surface in every direction. There is no such thing as negative pressure—only pressure lower […]

When I was a green tech, I was really big into showing up all the other techs by doing THE BEST cleaning I possibly could. One of my favorite things to do was to clean the condenser until it was SPOTLESS inside and out. The only issue was that I really liked using that brown […]

Does setting a thermostat too low cause an air conditioning system set in cool mode to freeze? The answer is no, at least not directly. However, low evaporator load (low return temperature or low airflow) and low outdoor ambient temperature can lead to evaporator coil freezing. Low indoor setpoint can lead to low return air […]

When a system has abnormally high head pressure (high condensing temperature over ambient) and compression ratio, one of the easiest things to look for is a dirty condenser coil. More often than not, that will be the cause. However… There is another category of issues that can cause high condensing temperature (high head pressure), but these […]

I wanted to share a recent “rediscovery” with you out of pure humility. I call it a rediscovery because it’s a basic fundamental I already knew, but it just hadn't come up recently enough to be top of mind until the other day. I found myself troubleshooting a single-pole Mars 91311 contactor. I had voltage […]

My family tries to live as holistically as possible. We make a lot of our own food and stay away from things that are heavily processed and have a lot of additives, preservatives, and common allergens. That means we like to buy snacks from independent brands that are transparent about their recipes, and one of […]

“It sounds very fancy, but it's really the HVAC of the spacecraft — controlling humidity, temperature and the whole atmosphere onboard.” — Manuel Retana, NASA Project Manager, ECLSS Artemis II  |  University of Nevada, Reno, April 2026 A NASA engineer who spent five years building the life support system on the Artemis II spacecraft name-dropped […]

There are many appliances with compression refrigeration circuits that do not have ports installed for testing, recovery, charging, and evacuation.  These can include window units, PTACs, fountains, refrigerators, and much more. This fact presents a challenge any time you suspect or know there is a refrigerant circuit issue. How can you diagnose and repair when […]

When we say that there is “flash gas” at a particular point in the system, it can either be a bad thing or a good thing, depending on where it is occurring. Flash gas is just another term for boiling. It is perfectly normal (and required) that refrigerant “flashes” or begins boiling directly after the […]