Common Air Conditioner Capacitor Failure Symptoms

Capacitor Failure Symptoms

are sometime harder to identify without the right tools and expertise. the most common symptom of a bad capacitor is that the motors do not run. This is especially true for the compressor. Fan motors can sometimes run even with a bad capacitor but hidden damage is still happening to the fan motor. Fan motors can also run intermittently with a weak or bad capacitor. There are not always visible signs that a capacitor is bad. But there are times when you will see either a balloon shape on the capacitor or a split and leak. But this is not always visible when a capacitor is bad. It’s best to have an expert check the capacitor. There is a high risk of severe electric shock if a capacitor mishandled. This is not a DIY repair.

Types of Capacitors

Capacitors can be found in several different sizes and shapes. There may be one or multiple capacitors included in your ac with regards to the design. While the most popular capacitors are the types found on circuit boards, the ones most associated with air conditioning will be the bigger capacitors that assist start and run your motors. There are several motors present in an conditioner and heater systems:

  1. Compressor Motor Run Capacitor: Here is the most popular capacitor that fails. Most of the time these are duel capacitors, which means that there are 2 capacitors built into one. A duel capacitor will have three terminals on the top where a single capacitor will simply have two terminals on top.
  2. Outside Fan Motor Run Capacitor: That is the smaller capacitor found with or part of the Compressor Motor Capacitor. It helps start and run the outside fan that blows air through the outside coils.
  3. Indoor Blower Motor Run Capacitor: Similar to the outdoor fan motor capacitor, it is a small, single (two terminals) capacitor that will help start and run the indoor blower motor.
  4. Start Capacitor: Some models include an auxiliary start capacitor that helps jump start the motors. Most are found on the compressor. These are less common.

Why do capacitors go bad

When capacitors go south, they either go out entirely or they decline in strength. The decline is measured in the “capacitance” units called micro farads. When the capacitors are produced, they are labeled with their specifications capacitance and a range +/- from the design capacitance. This range is the allowable operating range, usually labeled in a percentage range, for the capacitor. If the capacitor starts to fail, the capacitance measured will be outside of the labeled range. Sometimes these are difficult to find any symptoms unless you have the proper tools. Warning, there is a risk of severe shock, so do not try this at home.

Diagnosing a bad capacitor

If a capacitor goes out completely, or is severely out of its operating range, it may prevent the motor affiliated with it from running completely. If the compressor motor is not working, then the air conditioner will not cool. If the outside fan is not working the compressor may cause problems and will short cycle or cease working. If the indoor fan stops, you’ll find that there is no air blowing through the vents.

For Quick, Honest and Affordable Service, call

Alexander Heating and Air Conditioning

1-919-886-HVAC (4822)

Raleigh Air Conditioner Repair

Holly Springs Air Conditioner Repair

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Why You Need an Air Conditioner Tune-up

Why You Need an Air Conditioner Tune-up

It is almost springtime again in Raleigh North Carolina and people will soon be starting to turn on their air conditioners for the first time. Most air conditioners have been sitting idle through the winter and probably have not been checked for several months. Through the winter, the condensing units have been exposed to adverse weather conditions, clumsy landscapers, dust and pollen, dirt from construction sites, road salts from the traffic, dirty air filters, and much more. All these environmental conditions have a significant impact on the operation and life of your equipment.York Heat Pumps

The #1 cause for air conditioner failures is compressor burn out. All the dirt, pollen, dust, leaves, and landscaping mulch can build up on the outside coils and cause the compressor to overheat. When a compressor operates at elevated temperatures, the oils inside begin to breakdown and stop lubricating the compressor parts. Then the friction build up elevates the temperatures even more and soon your compressor will stop functioning.

It is Time for Your Air Conditioner Tune-up Today

Alexander Heating and Air Conditioning offers our Spring Tune-up services that will your coils, check all your components that wear out with age, and notify you if you need any R-22 added. Our Tune-up will give you the peace of mind that your system is in the best shape possible to prepare for the upcoming summer. Don’t wait for your system to breakdown during the busiest part of the season. And during the summer months, most companies are backed up with calls and will cause you to wait several days for a repair. Don’t be stuck without your air conditioning this summer. Call us today.



R22 Phase out

If you have been living with a refrigerant leak and your air conditioner contains R22, it’s about time you got that old junk replaced. In the last 4 years, R22 prices have more than quadrupled and and are expected to go up 50%-100% more by the end of summer. Most distributors are only allowing the purchase of one tank at a time to the HVAC service companies.

Some have offered drop-in replacements but the variety of 4531535_sreplacements out there make the task of servicing the unit 10 times harder if you do not know which replacement the previous technician used. Mixing the replacement refrigerants can further damage your system.

If you have not changed to a new system in the last 15 years, start getting your wallets out. The new systems will come with a bit of a sticker shock to most consumers. Expect to pay from $6000 to $8000 just for the entry level systems.

Check out our web site for more information on refrigerant leaks or new systems.

Why do HVAC Capacitors Need Replacing

Capacitors are very similar to batteries. They get charged up, hold this charge, then release it. The only difference between a capacitor and a battery is the amount of time it takes to charge and discharge. Batteries are slow to charge and slow to  discharge. Capacitors charge and discharge nearly instantaneous.capacitors

Several other properties are similar too. For example, they wear out over time, they have a shelf life, they lose their power capacity when exposed to extreme heat, and they can fail internally and leak. The one thing that makes them different also makes them dangerous. Since they can discharge in an instant, this means the current and voltage they hold can severely injure or even kill someone who does not know how to handle them.

The quality of a capacitor is dependent on the materials used to manufacture the capacitor. Some materials are better than others. There are capacitors that have 5 year warranties and cost more due to the materials. There are others that are made from cheap less suitable materials and the capacitors can fail within months.

HVAC technicians have a wide variety of choices from their distributors and sometime just go for the cheap brand so they can make lots of profit. Not to mention they get more frequent return visits. Most consumers are not educated on the brands or what to ask their technician. Check with your technician if he/she offers any kind of part warranty for your piece of mind.


Help! My heat is not working. I set my thermostat to 69 but my heat only gets up to 67 then it stops. What is wrong?

This sounds like a common problem that we run into many times during the heating season. It is especially common for people with image of digital thermostatheat pump systems. A heat pump system typically has two different heat sources, the primary heat and the secondary heat. The primary heat is supplied by the heat pump which is just an air conditioner in reverse gear. The secondary heat is usually electric heat strips similar to the plug in space heaters you find in many retail stores. This type of secondary heat is what is called radiant heat and is very inefficient. You can tell how frequently your system uses radiant heat by how high your electric utility bill gets in the winter.

This secondary heat is sometimes referred to as emergency heat or AUX heat on your thermostat. It Picture of resistance heat stripsusually will have an indicator light or some other indication on touch screen thermostats. It can also be the primary source of heat if the thermostat is manually set to AUX HEAT or EM HEAT. Setting this mode will turn off the heat pump and only use the secondary heat. But this is very expensive so only use this if your heat pump is not working and until the service technician can get it back up and working properly.

In our case, what is happening is that the heat pump is not working and the system is relying only on the secondary heat. With a properly matched thermostat, the internal program recognizes when the heat pump is struggling to heat the house in cold temperatures and initiates the secondary heat to help the heat pump. The program also limits this help to when the actual house temperature is 2 or more degrees below the set temperature. This restriction, which is built into the thermostat program, is why the house will never get all the way up to the set temperature with the malfunctioning heat pump and the thermostat on the normal settings.

The situation does require further investigation as to why the heat pump is not working, but the information provided here is not enough to make a proper diagnosis. That will require someone to put their test equipment on the unit. The home owner can switch the thermostat to AUX HEAT in the meantime and it will keep the house at the set temperature, but it will be very expensive to leave it that way for too long.