What a tune-up actually is
Before anyone sells you a plan, it is worth knowing what the visit inside the plan
consists of, because the word covers everything from an hour of real work to a man
hosing off your condenser and leaving a magnet on the fridge.
A real one is mostly measurement. Microfarads on the run capacitor, compared against
what is stamped on the can, because a capacitor that has drifted ten percent low still
starts the compressor in April and will not start it in August. Amp draw on the
compressor and the condenser fan. The contactor, checked for pitting on the points,
which is the cheapest part on the system and one of the most common reasons a house is
88 degrees on a Saturday. Static pressure across the air handler, which is the only
honest way to find out whether the duct can move what the equipment is producing.
Superheat and subcooling, which is how you find a charge problem before the coil
freezes into a block of ice and the compressor starts drinking liquid.
Then the boring half. The condensate drain, blown out and flushed, because in this
county the pan grows a biological slime that will fill the pan and trip the float
switch on the hottest afternoon of the year. The blower wheel, which collects a felt
of dust on every vane and quietly costs you a third of your airflow. The coil, washed.
The filter, actually changed, and the size written down somewhere so you can buy the
right one.
March is the cheapest month you will ever spend on your air conditioner, and October is
the second cheapest. Everything in the paragraphs above is easier, faster and less
urgent when it is 70 degrees outside and nobody is waiting in a hot house.