Air Conditioner Does Not Cool
A central air conditioner that runs but doesn't cool may just need to be cleaned. Plan to do this on a relatively warm day. First look for your owner's manual and, if you can find it, follow its instructions. If you can't find it, request one from the manufacturer.
1) Before you begin, turn off the power to the unit. There is normally a shut-off or disconnect panel on the house wall next to the outdoor compressor. Otherwise, shut off the air conditioner's 240-volt circuit at the main electrical panel.
2) Rake leaves and debris away from the outdoor condenser.
3) Remove any protective grille or cover from the condenser's fins.
4) Use a soft brush to clean dirt and debris from the fins, then vacuum them with a brush attachment (be careful not to bend or damage them).
5) Unscrew and lift the top grille off the unit, if possible. If the fan is attached to the grille, be careful not to pull any wires loose.
6) From inside the unit, hose out the fins (protect the wiring and motor with plastic). If your owner's manual calls for lubricating the motor, do that now - but don't over-lubricate.
7) Then reassemble the unit.
8) To test it, turn the power on and set the thermostat to turn the unit on. Let it run for a few minutes, then feel the two pipes that connect to the condenser unit (slide any insulation back). One should feel warm, the other cool. If they are not, call an air conditioning technician - because the refrigerant may need to be recharged.
Air Handler Squeals
Squealing sounds from a forced-air heat pump generally occur when the belt that connects the motor to the fan slips. If the blower is making a grinding noise, shut off the unit and call a heat pump repair technician - the motor's bearings are probably shot.
In most cases, the belt is improperly aligned or worn and needs replacement. Follow the instructions in your owner's manual. (If you don't have one, contact the manufacturer and ask for one.)
This job involves removing the access panel, loosening a couple of bolts that hold the blower motor at the proper tension, and realigning or adjusting the belt. In many cases, it's a good idea to remove it and buy a replacement at the hardware store.
When reinstalling the belt, be careful not to over-tighten it as this can wear out the motor bearings.
Air Ducts Are Noisy
Many heating/cooling ducts are metal, so they conduct noise quite readily from the air-handling unit to your rooms. To break the conduction of sound, you can have a heating contractor insert flexible insulation ductwork between the heating/cooling system and the ductwork runs.
If you hear a pinging or popping sound coming from the ductwork, this may be caused by thermal expansion or by air blowing past a loose flap of metal. Track along the duct runs, listening for the sound. If you find it, make a small dent in the sheet metal to provide a more rigid surface that's less likely to move as it heats and cools.
