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How to replace a faulty air-conditioner capacitor

How to Replace an Air Conditioner Capacitor

As summer approaches, your air conditioning system springs into action. But before you know it, you might want to know how to replace an air conditioner capacitor if the first switch-on after the coldest months suddenly reveals your AC unit has stopped working and is faulty.

One of the most common reasons an AC system fails is a failing capacitor. Unfortunately, they are an integral part of any AC unit, as they release energy to the compressor, blower, and fan. Firstly, you have to decide whether it is the start or run capacitor that you need to replace. They have different duties but they are easy to locate.

They are easy to replace, and any contractor will know what to look for when identifying a faulty capacitor. They will quickly and easily remove and replace it with a new one before the problem becomes bigger.

How to Spot a Failing capacitor

You will start to notice the capacitor failing on your air conditioner if your AC unit does not blow out cold air, is slow to start after switching on, or if the compressor starts to make a humming noise. If the capacitor starts to make a clicking noise or the AC unit refuses to stay on, these are further reasons why you should investigate changing your AC capacitor.

A degrading capacitor usually shows up in the above circumstances, so it can be quite easy to identify and replace before any major faults start occurring. Faulty caps can lead to a damaged fan or compressor, that’s when repair costs start to mount up.

Not blowing cold air when you are entering a hot season is not what you want, so keeping an eye on your AC unit and monitoring how it is working can save you a fortune.

Visually, the capacitor can also take on a swollen look when it starts to degrade. The top of the capacitor will start to look domed rather than flat, meaning you need to investigate replacing it right away.

Another visual sign of a faulty air conditioner capacitor can be a sticky or oily residue leaking from the top. This is a definite sign of a need to replace the air conditioner capacitor quickly to prevent further costly damage.

The purpose of a capacitor is to provide high voltages when fully charged, and although they are designed and built with safety in mind, they can become dangerous and cause electric shock if handled incorrectly.

Universal Capacitor

Precautions When Replacing an Air Conditioner Capacitor

Simple and obvious safety precautions apply when working with electricity and changing the capacitor in your HVAC system is not beyond the capabilities of a home DIY’er.

  • Avoid touching the capacitor terminals
  • Do not short circuit the terminals with a screwdriver or other metal object
  • A specialist should always be used to discharge the resistance load

How to Replace an Air Conditioner capacitor

Replacing a HVAC capacitor is an easy task and is essential before it causes damage to other parts of your air conditioning unit. Here’s a few simple steps to help you replace the capacitor.

  • Always switch off the power supply to the AC unit
  • Remove outside panels to get access to the capacitor
  • Check to see if the capacitor looks faulty using the symptoms described above
  • Make a note of the capacitor’s capacitance and voltage rating. You need the details to find the exact replacement for your faulty capacitor.
  • Make a note of wire layout and connections before dismantling everything
  • Discharge and dismount your air conditioner capacitor
  • Replace with the new one and connect the wires as noted before
  • Reconnect the power supply and test your AC unit

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Always replace your existing capacitor with an exact replacement or a universal capacitor that can be adapted to your required capacitance. If in doubt, contact your local contractor and always seek advice before touching electrical equipment.

See our selection of replacement parts here