AC repair in Pennsylvania

Air conditioning failures cluster into a handful of causes, and the first heatwave of the summer finds all of them at once. Here is what we actually diagnose.

The unit hums but the fan will not start

The classic failed run capacitor. It is the component that gives the fan and compressor motors the push they need to start, it degrades with heat and age, and it is among the most common air conditioning failures there is. It is also an inexpensive, fast repair — and one a maintenance visit catches before it strands you, because a weak capacitor can be measured before it fails outright.

It runs constantly but the house stays warm

Several possibilities, in rough order of frequency:

• A dirty condenser coil. The outdoor coil has to dump heat outside. Caked with pollen, cottonwood, grass clippings or dust, it cannot, and capacity falls while running costs rise.
• Low refrigerant from a leak. See below.
• A failing compressor drawing power without producing much cooling.
• Duct losses bleeding cooled air into a basement or attic. See ductwork repair.
• An undersized or oversized system for the house as it is now.

There is ice on the indoor coil or the refrigerant line

Counter-intuitive but common: an air conditioner freezes when it cannot get enough warm air across the evaporator coil, or when it is low on refrigerant. The practical causes are a clogged filter, a blocked return, a failing blower, or a leak. Turn the system off and let it thaw before calling, and do not run it while frozen — liquid refrigerant reaching the compressor is how an expensive repair becomes a replacement.

Water around the indoor unit

An air conditioner pulls a great deal of moisture out of Pennsylvania summer air, and that water has to drain. A clogged condensate drain backs up into the pan and then onto the floor, the ceiling below, or into whatever is nearby. Many systems have a float switch that shuts the unit down to prevent exactly that — so an air conditioner that stops on a humid day, with water in the pan, is often a drain problem rather than a cooling fault.

It cools but the house feels clammy

This is the Pennsylvania-specific complaint. Dehumidification happens while the system runs, so a unit that is oversized satisfies the thermostat quickly, shuts off, and never runs long enough to pull moisture out. You get a cool, damp house. The fix is sometimes a blower speed or staging adjustment, sometimes honest advice about sizing at replacement time, and occasionally a separate dehumidification solution.

The breaker keeps tripping

Do not keep resetting it. A repeatedly tripping breaker is reporting an electrical fault — a shorted compressor, a failing motor, a bad contactor or a wiring problem — and resetting into a fault risks damage and fire. Leave it off and call.

Heat pumps in cooling mode

If your outdoor unit also heats the house in winter, it is a heat pump, and its cooling-side faults are the same as any air conditioner's plus the reversing valve. See heat pump repair.

Repair or replace

Capacitors, contactors, fan motors, drains and coil cleaning are all routine repairs worth doing at almost any age. The calculation changes with a failed compressor, a leak in the evaporator or condenser coil itself, or a system more than twelve to fifteen years old needing a major part. We quote the repair and give you the comparison rather than leading with a replacement.

What you can check first

• Thermostat set to cool, and the fan set to auto.
• The filter. A clogged filter causes a startling share of summer calls.
• The outdoor unit clear of grass, leaves and shrubs, with about two feet around it.
• The condensate drain running freely.
• Both breakers — indoor and outdoor units are often on separate ones.