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How to Replace Central Air Conditioning

Air conditioning units have become almost a necessity for many people around the world. A broken or underpowered unit will be unable to keep a home or office cool, and may need to be replaced. Most units come in two forms, split systems and package systems. Split systems can be extremely difficult and costly to replace on your own. The appropriate tools to replace such a unit, such as a refrigerant recovery machine, can often times be more costly than professional installation.

Package System

Replace Central Air Conditioning
  1. Shut off all power to the house. Also shut off the gas line outside of the unit.
  2. Disconnect any wiring and gas lines connected to the unit.
  3. Remove the old unit and replace it with the new one. The unit might be bolted into place, in which case remove the bolts first. Bigger units may require a professional tool to lift off the ground, while most units can simple be picked up by a two to three people.
  4. Reconnect the gas lines and the wiring.
  5. Turn the power and the gas back on.

Split System

  1. Shut off all power to the house.
  2. Use a refrigerant recovery machine to empty the system of the refrigerant inside. Each tool is slightly different in its use, so make sure to read all of its instructions carefully, and use as directed. It is illegal to allow refrigerant to escape into the atmosphere.
  3. Disconnect the air conditioning unit from all tubes and wiring connected to it.
  4. Remove the old unit from the ground and replace it with the new one. The unit might be bolted into place, in which case remove the bolts first. Bigger units may require a professional tool to lift off the ground, while most units can simple be picked up by a two to three people.
  5. Reconnect all tubing and wiring to the new air conditioning unit.
  6. Connect one end of a set of gauges to the service port of the AC unit and the other end to a vacuum pump.
  7. Turn on the vacuum pump and evacuate the system of all air. Keep the pump on until the pressure of the system reads 0, then turn it off.
  8. Let the system sit for an hour at 0 psi. If the pressure remains at 0 when the hour is up, proceed to step 9. If the pressure has gone up, the system possesses a leak. Make sure all the tubing is securely fastened and try the test again. If the pressure still rises during the hour, consult a professional.
  9. Remove the vacuum pump and attache a cylinder of refrigerant to the gauges. Charge the system to the appropriate psi per the specifications of the unit.
  10. Remove the cylinder and the gauges from the service port, and replace the cap onto the service port.
  11. Turn the main power to the house back on.

Things You Will Need

  • Refrigerant recovery machine (Split System)
  • A/C system gauges (Split System)
  • Vacuum pump (Split System)
  • Refrigerant cylinder (Split System)
  • Bolts and a ratchet
  • Wrench

Tip

  • Make sure the entire unit needs replacing before opting to change it. It is often possible to fix the unit at a much lower cost than replacement.

Warning

  • Be sure that power and gas going to the unit are shut off before beginning any work on it.

Resources

Photo Credits

  • By DaynaT