This was sent to me by Thomas Ask, P.E., associate professor at Pennsylvania College of Technology and I thought I would pass it on to my three readers:

It is difficult to drive theoretical concepts into the minds of students who like to work with their hands. What I ask all students to know when they complete my courses is a list of eight critical truths related to HVACR. This list is asked for both on the midterm and final exams. This is an imperfect list; however, it endeavors to lock in critical knowledge that the HVAC professional must always consider in his or her work.

HVAC professionals must always know the following:

• HVAC equipment is Heavy, check load bearing ability of structures and floors.

• Poor combustion results in undetectable CO, which can kill people.

• Fuel can Explode at certain fuel to air ratios, which can kill people.

• Things eXpand when heated and contract when cooled, which can tear apart systems.

• High surge Pressure is produced by the closure of fast acting valves, which can tear apart systems.

• Smoke travels through ducts, which can kill people.

• Water expands as it freezes, which can tear apart systems.

• Refrigerants can suffocate people.

I have developed the following mnemonic that is helpful in memorizing these key concepts: Heating and Cooling EXPerts Set World Right. Most professionals would add many more items to this list but I believe these eight facts encompass important safety and catastrophic destruction concerns in mechanical systems.