Hey guys, HVAC is a huge trade encompassing heating air conditioning and ventilation put an R on the end and you have refrigeration. It is usually broken down into separate trades, tin bashers install the duct work and furnace. Gas pipers is a separate trade again and so is air conditioning. To SERVICE all the above is where you get a technician who is usually an apprentice refrigeration or journeyman. It is not like your regular trades, ie plumber, carpenter, bricklayer, its H V AC R. The problems you guys have been disgussing here about mismatching coils is simple, it is bad practice, but it is done and the indoor coil (in case we are talking heat pumps as well) should only be one size larger, not smaller. Pipe sizing is set for refrigerant velocity to ensure proper oil return to the compressor. The problems generally show up on retrofit systems where you get salesmen sizing things up improperly and putting in that oversized or under sized coil, a new apprentice with little experience installing it. Then it doesn't work, the warranty expires, a tech comes in and discovers all the screw ups. I am just wondering why you guys are busting a nut over this? The standards state clearly that we don't do capacity or adequacy or efficiency or any engineering. Seems to me if we guys were to stick to our own standards of observe describe and report, we would have less to worry about. I have spent 30 years in HVAC Canada and I've seen it all and all I do is write down the model and serial numbers and don't worry about the rest, if I have any questions about the system I defer it to the "EXPERTS" and let them figure it out.