General HVAC in Kingston, NY

Called out for a general HVAC diagnostic — homeowner said the system had been running strangely for a couple weeks, short-cycling and not holding temperature. Pulled the blower compartment and found the run capacitor on the air handler was starting to read low, but that wasn\'t the whole story — the real issue was a filthy evaporator coil restricting airflow enough to cause the system to trip on high-limit repeatedly. Cleaned the coil with Nu-Calgon coil cleaner, swapped the capacitor since it was already at the low edge of tolerance on a unit that looked to be pushing 12 years old, and verified static pressure before and after. Airflow came back up significantly, system cycled cleanly through four full runs before I closed it up. Homeowner hadn\'t had anyone look at the whole system in at least three years — told them to get on an annual schedule because this kind of buildup doesn\'t show up overnight and it adds wear fast.