Introduction Replacing a reversing valve is either every technician’s dream or nightmare. The sheer amount of brazing involved in confined spaces will inspire either delight or nightmares about the upcoming valve replacement. Fortunately, these emotional highs and lows are uncommon because we don’t diagnose and replace bad reversing valves very often.  That itself poses a […]

In order to wrap my head around diagnostic issues, it helps me engage in thought experiments where I think of more extreme examples of an issue or situation or consider the ideal to find the “edges” of a concept. Once I find the extreme edges, I can begin to sort down to a more exact […]

Air changes per hour (ACH/ACPH) simply describes how many times the quantity of air in a room (or structure) is completely replaced per hour. If you have a 10'x10'x10′ room, the room contains 1000 cubic feet of air. If the supply and return to the room is supplying a balanced 100 CFM (cubic feet per […]