What Do Strange Noises Coming From Your AC System Mean? (And how to fix them)

[@tailzzzzz]

Ever since an HVAC tech replaced a capacitor on my exterior unit, my thermostat makes 2 clicks when I turn it from off to heat or cool. There are, also, 5 minute delays when switching from heat to cool and immediately back to heat and vice versa. Unit doesn't stop immediately, if I turn it off after turning the temp up or down in quick succession...maybe a few seconds delay. The thermostat, also, behaves differently in that it now runs beyond the desired temperature on the display, but refrigerator thermometers balanced on top of the thermostat and one on the table always read the desired temperature indicated on the display when it finishes. Trying to figure out why when I turn the heat from 69 to 70, the thermostat will reach 70, but continue on until the refrigerator thermometers read 70. I replaced the thermostat with a new one, identical brand and model. These are non-programmable thermostats, but I know another HVAC tech had to program something into it by holding certain buttons down to get 'emergency heat' mode as an option. It can't be my thermostat since this happens with both the old one and the new one. Some KZbinrs say there is supposed to be a delay before the unit responds to protect the compressor, but I found one who said there was a short or blown fuse on the exterior unit. Regardless, changing temp or modes always triggered an immediate response, no delays of any kind and the unit stopped at the desired temp I'd selected. Any clue? I just know neither thermostat behaves as it did before that capacitor was changed. The system is 6 years old, forced air electric heat pump, but only 4 years of normal use because the house sat for a while, so I kept the house very chilly in the winter (50 degrees) and warm in the summer (probably 80-85 degrees).