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5 Common Reasons Your Air Conditioning Fails

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There’s nothing quite like waking up in the middle of a sweltering hot and humid night to find out that your air conditioner is on the fritz, or worse yet — has stopped working entirely. Not only can this make for exceptionally uncomfortable temperatures inside your home, but it can also be a health concern for seniors, young babies, and even pets. 

When it comes to a failed air conditioning system, there are hundreds of potential causes, but here are the top five that we find:

  • Faulty electrical component/wiring
  • Clogged condensate lines
  • Dirty evaporator coil/air filter
  • Refrigerant leaks
  • Broken thermostat

Let’s take a closer look at these reasons your air conditioning can fail and some potential solutions for addressing them. 

Faulty Wiring

1. Faulty Electrical Component or Wiring

Faulty wiring in the thermostat, A/C unit, or even your house can be responsible for these devices not working. A/C units require a lot of power, especially during startup, and if your home’s wiring has a fault, it’s likely overloading the circuit and shorting the most vulnerable components of the air conditioning system. Diagnosing your home’s electrical wiring on your own is a bad idea. These lines carry fatal voltage levels, and working on live wires is unsafe even for electricians wearing special clothing to protect against electrical arcs.

Solution: If you need to reset the circuit breaker, be sure to wait at least 15 minutes to allow the compressor to cool down before turning it back on. If it continues to trip, then it’s time to call on a professional for help. Our technicians can help diagnose the problem and inspect related issues, such as the pressure limit switch.

Clogged Lines

2. Clogged Lines

Can you say Zoogloea? This may be a new word added to your vocabulary today! Zoogloea is a type of bacteria that is commonly found growing at rapid rates in many air conditioning drain lines… think of the Swamp Monster from Goosebumps!

Okay, it’s not that bad. However, blocked drains are certainly the number one problem we come across here in the tropical climate of the Cayman Islands. Clogged AC condensate lines result from improperly designed drain pipes, absence of Ultra Violet (UV) lights to destroy microbes, and, most importantly, lack of regular air conditioner maintenance. 

Solution: While you can clean your air conditioner’s condensate drain line yourself, there are many very important things to know beforehand. For example, after clearing the line, the drain trap must be reset to prevent humid outdoor air from being sucked into the air handler through the drain pipe. If you are having ongoing issues and you cannot figure out why your AC drain line keeps clogging, it may be best to have a professional assess the entire system and sign up for a reliable air conditioning maintenance plan. Another solution to clogged A/C condensate lines could be redesigning the drain system to ensure sufficient slope and proper sizing of the pipe. Lastly, by installing UV lights we can deactivate any microbes before they start to grow on the air handler coil or drain pan. These two components tie directly into the drain line and, if they have Zoogloea, drain blockages become more likely downstream in the drain line. 

Dirty Coils

3. Dirty Evaporator Coils/Air Filters

It is at the air handler evaporator coil where all the action happens. This critical component absorbs heat and removes moisture from the return air, resulting in cold and crisp air supplied to the conditioned space. However, after some time and hundreds of tons of air passing through the coil fins, dust, grime, and mineral deposits from the salty ocean air build up on the evaporator coil. When the air handler coil is covered, it doesn’t effectively absorb heat from the air, forcing it to run harder to cool your home. This increased pressure can overwork the air handler blower motor, the outdoor compressor, or the outdoor condenser fan motor and cause any of these critical and costly components to fail. Not to mention the increase in your energy bill at the end of each month! The same effect can be caused by dirty air filters because they can obstruct airflow if not changed at least every 3 months. Many homeowners are unaware of the impact of clogged air filters on the operation of their air conditioning system and monthly energy bill.

Solution:  Regularly changing air filters is the first line of defense against dust and dirt buildup on A/C evaporator coils. If you haven’t had regular service on your system over its lifespan, and you suspect it might already be dirty, there are a number of solutions to consider. A thorough in-place cleaning may do the trick. This involves using a small mobile pressure washer to clean the sludge out from between the coil fins. The correct cleaning solution must be used as some acidic cleaners can eat away at the coil and cause an even bigger problem. Special tools are needed to reach the nooks and crannies of the coil. If the sludge buildup is advanced, it may be best to completely remove the coil so that it can be taken outside and cleaned even better. This takes much more time and is more expensive. Lastly, installing UV lights help to prevent the growth of microbes on the evaporator coil. This is a great option because it is like having a tiny AC technician cleaning the coil and air handler 24/7!

Refrigerant Leaks

4. Refrigerant Leaks

As you can probably imagine, refrigerant is an essential part of any air conditioning system. Over time, the components that hold refrigerant can corrode and slowly leak. These refrigerant leaks can occur in the evaporator coil, condenser coil, filter drier, and at joints in the refrigeration system. There are also some occasions where leaks occur from poor manufacturer welds at joints. A specific type of corrosion that is common near coastal areas is called formicary corrosion. This is where very tiny organic acids from the air collect primarily on evaporator coils and create pinhole-sized leaks by eating away at the system. These are believed to be most common in very airtight homes that have little introduction of fresh air because there are many household items that release, or offgas, these organic acids — cleaning products, candles, paints, carpets, cooking fumes, drywall, wood floors, etc. In airtight homes, these compounds are highly concentrated and are more likely to cause leaks in the air conditioning refrigeration system. 

Solution: There aren’t always preventative measures to avoid all types of refrigerant leaks, however, there are things you can do as it specifically relates to formicary corrosion. The introduction of fresh air using an Energy Recovery Ventilator (ERV) can help to reduce the levels of organic acids in the home. Another more budget friendly option is to install an oxidizing device that breaks down these organic acids. Introducing fresh air not only benefits the air conditioning system but also has proven positive health effects. Limiting the number of chemicals and gases (including organic acids) floating around in the air in your home is shown to ease various medical symptoms including dizziness, headaches, nausea, blurred vision, lethargy, memory lapse, and lung problems. 

Broken Thermostat

5. Broken Thermostat

Sometimes the A/C equipment is working just fine — the problem is actually in the thermostat. If the temperature in your home feels dramatically different than its setting, it could be due to a faulty, uncalibrated, or improperly placed thermostat. If your thermostat display is not powering up, the first thing to do is replace the batteries. If that doesn’t help, there may be an internal short in the thermostat. Alternatively, your air conditioner’s safety float switch may be engaged and braking power to the thermostat. The thermostat may not be faulty at all, just uncalibrated or improperly positioned. For example, if the thermostat has been installed on a wall that gets direct sunlight, it will affect its accuracy and performance. 

Solution: If the thermostat is not turning on, you may try replacing the batteries first. The second thing to check is the circuit breaker and/or the safety float switch located on the condensate drain line of the AC air handler. It is important to handle the float switch with care, as repeatedly engaging the switch may damage the compressor. For this reason, it may be better to have a professional do these checks. A reputable air conditioning service provider will be able to confidently diagnose the problem. Sometimes the only fix is to have a professional replace the thermostat, reposition it, or recalibrate it. They will also be happy to discuss the option to upgrade to an automated or learning thermostat that can automatically control and schedule your cooling program to optimize energy usage and maximize savings.

Bonus Reason — Old or Worn-Out Parts

There’s another common reason your air conditioner could fail — it’s old. Over time and regular use, everyday wear and tear can slowly break down the components of your air conditioning, which can negatively affect its performance. Not only that, but parts like your compressor, electrical components, and fan blades can break down simply due to regular use. 

Solution: If you want to save yourself that emergency air conditioning repair call in the middle of the night, invest in regular tune-ups and other maintenance from our team of professionals. We can inspect your entire system and replace old or worn out parts. Fixing the small issues now can help prevent inconveniences and more significant problems in the future, so rely on our air conditioning maintenance services to keep your system performing at optimal capacity for years to come. 

Some of these tips and tricks can be performed yourself, but don’t be afraid to call a professional to assist when necessary. HVAC is a complicated subject, and our workers are trained and certified in what to do. Give us a call to find out how we can get your A/C unit back up and running today.

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