Dan has been in the HVAC industry for 23 years with experience ranging from installation and service to sales and distribution.
Air Conditioning Basics
If you're having work done on your air conditioning system you may be like many homeowners out there...in the dark. Like many specialty areas of service, air conditioning is something that most people know nothing about and therefore feel vulnerable when having service work done. You want to feel confident that your money is being spent wisely and that the work you're receiving is needed, right? Well the best way to feel more confident about these things is to educate yourself.
The following information will not make you a professional HVAC technician but it can help you to understand some of the basics of air conditioning and somewhat makes sense of what you're being told by your service provider. The result will be the feeling of confidence that you're not being taken to the cleaners.
Get To Know Your A/C
1 - Regular Maintenance
Maintaining your HVAC system is a must. Particularly when dealing with your A/C system, maintenance is of the utmost importance. Quite often, air conditioning service calls are related to lack of maintenance. The good news is, much of this can be done yourself.
Air conditioning is very temperamental. Dirt building up on the filter, outdoor unit and in the evaporator coil located on top of the furnace is often very problematic to your system. This is because the air conditioning system operates based almost entirely on a pressure/temperature relationship.
The airflow passing through the furnace fan, over the evaporator coil and over the condenser coils plays a major part in this relationship. If dirt is building up in these areas, the airflow is then restricted causing higher temperatures and thus resulting is higher pressures. The end result is the refrigerant running through the system in "states" that aren't intended for the system.
There is a whole lot of science involved in the process of refrigerant converting from gas to liquid and so on to provide the proper de-humidification for your home. I don't want to overwhelm you with this information so just understand that regular cleaning of your system is very important. It will extend the life of your parts, increase the efficiency of operation and save you the discomfort and cost of simple breakdowns that could've been avoided by cleaning.
Keep Your Refrigerant
2 - The "Charging Your System" Mistake
Often we are told that air conditioning systems are in need of charging. This may be true in some cases but is often misdiagnosed or the leak is not repaired.
Understand that an air conditioning system is a sealed system that is to be extensively leak checked upon installation. Once the system has been checked, it should not leak unless something has impacted the unit. (broken part or seal, heavy damage by a storm or collision, etc...)
The thought that an air conditioning system just needs to be recharged every so often is a myth.
Though it's a good idea to check the charge of the system, especially if you didn't have it installed, don't do this on a regular basis. If the system is low, ask that the leak be found and repaired. If you don't, you'll be looking at a yearly bill to charge the system and aren't doing the environment any favors (meaning the environment in and out of your home depending on where the leak is).
Once the unit is said to be leak free, don't have the pressure checked unless there is a problem with the system again. Every time the gauges are hooked to your system, it is inevitable that refrigerant is stolen from it. Over time, this will add up and you will end up needing a charge.
Again, the pressure/temperature relationship of an air conditioning system is very finicky. Slight adjustments to either of these 2 factors can result in problems with the system.
Air Conditioning Tip
If your A/C is humming but the outdoor fan is not spinning, it may very well be the capacitor. Without getting into the service panel, you can take a small stick and try to give the fan a push. If the fan starts to spin with your "boost", it's almost gauranteed that the capacitor is bad. The good news is replacing a capacitor is easy.
3 - It's Often an Electrical Problem
Air conditioning repairs are often electrical. Three very common problems are blown fuses in the service panel located outside near the condensing unit, tripped breakers at the main electrical panel and blown capacitors. Checking these items first could potentially save you a service call or at least provide confidence that you know what the service should be.
Listen to the outdoor unit...is it humming? If not, it's quite likely that your not getting power to the unit as a result of a blown fuse or tripped breaker.
Is it humming but not running? It may very well be the capacitor. The capacitor is a small silver part in the service panel that is usually round or oval shaped with a dozen prongs on top. Do not attempt to mess with the part but visually you should be able to see if the top is "mushroomed". This is a tell-tale sign that it is blown and at least you know when your service technician shows up, what the repair is likely to be.
4 - If Something Is Wrong It Will Let You Know
Aside from shutting down, air conditioning will usually let you know something is wrong before there is a shut down that is not electrically related. Routinely check the copper lines in your system for frost or ice. If you see this, your air conditioner is telling you that something is wrong and you may be able to have service performed before it shuts down completely or the problem becomes worse.
Air Conditioning Is Complex Science in a Simple Package
Air conditioning is a simple system that uses complex science but this basic knowledge is what's most important to you as a homeowner and can protect you from allowing certain mistakes to be made.
Want More A/C Knowledge?
- Central Air Conditioner Parts
Learn what your air conditioner is made of and what parts you may very well be able to replace yourself if there is a breakdown. Easy to follow explanations with photos.
- How to Buy Air Conditioners
The best way to make any significant purchase is with sufficient knowledge. Buying an air conditioner is no different. This hub will provide you a basic understanding of an air conditioning system's parts and functions, buying considerations and offe
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
© 2012 Dan Reed
Christine vaughn on August 31, 2020:
Thermostat cool blinks n i think that means it's in delay mode its humming the fan isn't spinning I turn it off and the fan kicked on I turned it back on fan shut off under the thermostat plate i reset it n flipped the black switch n for Amin the fan came on ac bl we in seconds later it cut off I've replaced fan motor cleaned the unit airflow replaced the fuses the capacitor looks fine it stays in delay mode .it only started after I wired the light outside my house wrong it tripped the breaker I replaced the breaker because after I shutdown the breaker I got no power to the light. I don't know what else it could be I've had two people so far what I was told first the second opinion said that the first guy had no idea what there talking about so I'm stuck in the middle n if anyone can help plzz
carlos53 on September 14, 2019:
am an ac tech an we charge a service call to diagnose you all ac system i have found that systems do have a small leak in valves outside condenser this makes the system be low on Freon many times my tech replace those valves and the issue gets resolved they very small valves also i charge hourly plus the service charge is on the invoice of all my clients remember i had to send a tech over pay him hourly wage i have to put gas on that van truck and miscellaneous parts
Ramona on August 31, 2019:
If the ac blower is out will it still blow?
Osvaldo on August 14, 2019:
The fan is no working .. Am need onther
Zil on August 05, 2019:
I don't know what is wrong with my air conditioner, it seems working, but not enough coming out of any registers ( set to 69F)
Ice2rink on July 11, 2014:
Thanks Cre8tor for the info. The posts in this string are very educational. Thanks again
lyns from USA on July 10, 2014:
Excellent and very informed hub on the AC I wondered why my AC wasn't working properly this hub have given me some great insight thanks for sharing. 7101411a lyns
Dan Reed (author) on July 04, 2014:
Ice2rink - Not usually but yes it's possible and yes there are overloads in place. It would be hard for me to confirm or deny any suspicions that his work and diagnosis were lacking without knowing how he drew his conclusions and what tests he ran. That said, there are often problems that a tech sees and repairs while "stressed" components aren't as detectable thus leaving him looking bad when they show their heads a few days later. There are also problems that should've been detected but weren't because the tech hurried and didn't go as far as he should've in his diagnosis. I'm sorry but I would have to have a long conversation with the tech and you to see if you were shafted or just a victim of circumstances which is what I believe you're looking to find out.
Ice2rink on July 03, 2014:
If a capacitor fails and the system isn't shut down is the compressor in danger of burning up? I had a system diagnosed with a bad capacitor and fan motor - tech changed them out. A week later it stopped blowing cold air and tech diagnosed that heat from system inning without the fan cooked the expansion valves and compressor. Wouldn't there be some type of preventive overload breaker to protect the system from this?
furniturez from Washington on August 08, 2012:
Regular maintenance is extremely important, just like a car, if you don't stay on top of the upkeep it's not going to last!
Dan Reed (author) on July 04, 2012:
summerberrie on July 04, 2012:
Vincent de Jong on April 10, 2012:
Great hub. Very informative. Voting up!
Dan Reed (author) on March 22, 2012:
Thank you wayseeker. I'm glad it's helpful. There is a lot of science that I tried not to get into but for yourself or anyone else...I am open to questions that may give further explanation of this information.
wayseeker from Colorado on March 22, 2012:
This is marvelous information in an area I know next to nothing about. I just call when it doesn't work. Doing some simple self maintenance is a great idea as I do that with some other things around the house, but not the AC. I love the link to your other hub on this and I'll keep this one in my personal bookmarks so I can give it a try when I have time.
Thanks so much for saving me some money!