Today while browsing, I saw an interesting ad for system performance checks. Everyone always feels more is better, 44 ounce soda for a $1.oo is better than 12 ounce soda for $1.00. I see the same behaviors in air conditioning check ups and air conditioning tune ups. The real issue here is what’s checked before and after and what should a maintenance plan actually include? I can check 85 items, even 90 if I track every single step I take in inspecting and cleaning.
The point here is more is not always better! The quality of the inspection and maintenance check is more important that quantity. Let’s walk through a typical 100% commission based tune up. The technician will ask a few questions, go to the unit turn it on and run it for a period of time. The tech will then return with a series of recommendations that are required to keep the unit running, coil cleanings, capacitors and contactors are the hot ticket items.
Lets break this down further. A contactor that is showing signs of charring should be replaced. I’ve included a picture here to help you understand what a charred contactor looks like. Any capacitors that are bulging or swollen should be replaced as well. When testing a capacitor it must be tested at applied voltage with the unit running. You measure the through put amperage into the capacitor and the voltage across the terminals. The tech must perform a calculation to determine if capacitor is bad. Capacitance=(2851*amperage)/voltage. So if the capacitor is not swollen or bulging and the tech cant answer the two questions of amperage and applied voltage, don’t buy it, they are lying to make a sale.
Another tip is refrigerant charge. The refrigerant charge cannot be checked without verifying airflow, clean indoor coil and a clean outdoor coil. The two critical properties of refrigerant are subcooling and superheat. Cleaning and outdoor coil can add 5defgrees of subcooling which is a lot. How much refrigerant should be added before its a concern? more that 15% of the system capacity. So a typical system holds about 12 pounds of refrigerant. So the limit is 1.8 pounds of refrigerant but a leak must be sought out and repaired according to the EPA or it’s in direct violation of the clean air act.