Tag Archive for: HVAC

What Is a Capacitor and Why Do They Keep Failing?

Assortment of generic electronic capacitors

Many of our service calls are very simple: a blown capacitor. This is good for our customers because capacitors are comparatively inexpensive and quick to replace. Unfortunately, capacitors are a little bit like light bulbs. It might last 3 days. It might last 3 months. It might last 3 years, but it is very hard to tell how long they will last. Thankfully, our expert technicians at Mode Comfort can assist you with any AC issues. 

What Does a Capacitor Do?

The capacitor is the part of a unit that stores and dispenses electrical energy to make the AC or heat pump run. The electricity from the capacitor runs the motors, such as the compressor, the fan motor, and the blower. The main job of a capacitor is to jump start the AC unit or heat pump. Without the capacitor, your unit will not start consistently or run to its top capacity, leading to less quality AC. 

What is the Difference Between a Start Capacitor and a Run Capacitor?

Start capacitors give a jolt to the system to get the compressor and fan motor going. Run capacitors provide the oomph to keep the system running. They might be little, but without them, your unit is essentially dead.

How long do capacitors last for?

Capacitor lifespans can really vary based on the type of product and the conditions with which the AC or heat pump runs. The common HVAC capacitors that you see in many homes can last between 5 and 20 years. The capacitors that are used in industry-sized units can last for much longer. Thankfully, though, doing upkeep on your AC unit or heat pump can result in not needing replacement for 15 to 20 years. At Mode Comfort, we offer HVAC Inspection programs where our technicians maintain the upkeep of your unit so that your capacitor lasts as long as it can.

HVAC compressor on the side of a home

Why Do So Many Capacitors Fail?

1. Overheating

Capacitors fail if they are in direct sun for too long or if they run for too long, contributing to failure in the air conditioner fan capacitor. 

2. Open capacitors

Sometimes there can be breaks in the circuit of the capacitor, which stops the flow and renders the machine inoperable. 

3. Dielectric Breakdown

Sometimes AC units require high voltage capacitors, which can cause the dielectric materials within the capacitor to break down and fail.  

4. Environmental Factors

Areas that experience intense humidity or extreme weather environments may have earlier AC capacitor failure. Hermetically sealed capacitors are recommended if you live in these conditions. If your AC unit is near any sort of corrosive chemicals, this could damage your unit as well.

5. Service life

As with any appliance, AC units and heat pumps have prospective lifespans. If an AC unit or heat pump is nearing the end of its lifespan, the capacitor may begin to fail. 

6. Insulation resistance

The insulation in the machine is what keeps it from having any sort of electric shock. If the insulation begins to decrease, there can be more frequent short circuits that cause the capacitor to fail. 

7. Capacitance

The capacitance of a device describes its ability to store electric charges. Unfortunately, sometimes the capacitance can exceed the limit for a device, causing it to burn out. 

8. Vibration, acceleration & shock

Any sort of mechanical movement that is not routine for a device can disrupt the function of the mechanisms inside and cause issues with the circuit’s function. 

9. Dissipation factor

The dissipation factor (DF) for a capacitor is the measure of how much energy is lost and dispelled as heat when the AC functions. A low DF is preferred for efficient usage, but a high DF can burn a machine out quickly. 

10. Barometric pressure

Large changes in air pressure can put a lot of strain on an AC or heat pump, and can result in a faulty capacitor. 

11. Radiation

Radiation can be one of the most harmful things to impact a capacitor. If a unit is exposed to radiation, it can degrade the materials and lead to complete breakdown of the unit permanently. 

If you think your capacitor may be failing, it is imperative it is caught and replaced early. Running your unit with a failing capacitor can cause major (and expensive) damage. A dead capacitor can take out a motor or compressor with it, and possibly even cause the unit to fail entirely.

But How Do I Know If My Capacitor is Failing?

You probably won’t know the common air conditioner capacitor failure symptoms, but we will! Preventative maintenance is the key to getting ahead of potential issues. Mode’s Fan Club is only $19.95 per month (for one unit) and that includes two preventative maintenance visits per year. One inspection can cost $150-$200…you can do the math. During these check-ups, we will inspect all aspects of your comfort system, including your capacitors.

There are a few signs of possible capacitor failure modes that homeowners can look for in between check-ups to (although there can certainly be other causes to the below):

  • The compressor struggles to start and then shuts off quickly
  • The unit starts and stops over and over
  • The AC or heat pump is not blowing cold air
  • A humming noise
  • A clicking noise
  • Your system is performing differently than it previously had been

HVAC tech working on compressor on roof with supervisor looking on

Can I Replace a Capacitor Myself? Or Should I Call Mode Comfort? 

We do not suggest that homeowners ever attempt to replace a capacitor themselves, as it stores an electrical charge and contains hazardous oil. This is one piece of equipment best left to the HVAC professionals.

At Mode Comfort & Air Quality, we have technicians with the expertise to ensure that any issues with your HVAC are handled with precision and speed. Contact Mode Comfort & Air Quality at 804-481-6633 or admin@modecomfort.com today to hear what we can offer you. 

FAQs:

What happens if a capacitor fails?

At first, a capacitor failing may lead to less efficient cooling, but not handling the issue can lead to permanent breakdown of the unit. 

Do capacitors slowly fail, or is it just one day they won’t work?

This can vary! Many capacitors fail over time due to wear and tear, but sometimes they can fail quickly from electrical breakdowns or damage to the machine. 

What does a blown capacitor look like?

Things you should look out for that indicate a blown capacitor in your AC unit or heat pump is a bulging top, a broken casing, leakage of electrolytic fluid, or burn marks. 

How to prevent capacitor failure in a circuit?

The best way to avoid capacitor failure is to hire regular maintenance from a trusted HVAC company. If you’re looking for quality service in the Richmond area, give Mode Comfort a call today. 

What are the common problems in capacitors?

We discuss all of the capacitor problems you may encounter in the article above, but the most common are loss of capacitance, leakages, physical damage, and short circuiting.

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Open Vents for Proper Airflow

All of them? Yes, all of them. Even the one in the bathroom that is always freezing cold? Okay, you can close that one.

Depending on many factors, the cost of heating and cooling your home can be responsible for as much as half of your electric bill. At Mode Comfort & Air Quality, we are often asked by homeowners what they can do to lower their energy costs and increase the efficiency and lifespan of their comfort systems. The first response to this question is another question:

Are all of your vents open?

You likely have a return register that is non-adjustable (just a grille), but your supply registers (through which air gets pushed through the house) will have a means to adjust them. It seems perfectly logical that if a grille is adjustable (like window blinds), then you should be free to adjust it, and many people do just that.

Wait, are you saying I shouldn’t touch the lever on the vent cover once it is opened?

Closing even a few vents can cause problems for your system. Issues can be minor, such as low air flow or condensation, or major, such as a dead compressor or a cracked heat exchanger.

Many homeowners tell us that they thought that by closing a vent or two in an unused room they were asking the unit to “work less.” The marvelous world of HVAC does not work this way. By closing vents, you are actually restricting the duct system by increasing the pressure in the air ducts, which could cause leaks. Believe me, no one wants leaky ducts. Energy Star reports that “In a typical house, however, about 20 to 30 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts. The result is higher utility bills and difficulty keeping the house comfortable, no matter how the thermostat is set.”

Here is the technical part, in case you like numbers.

Air conditioners have to move a certain amount of air all the time. For instance, a 3-ton air conditioner is designed to move 400 cubic feet of air per minute (“CFM”). This flow can be raised or lowered 25 CFM without much impact on the unit (such as closing the vent in the bathroom that is always freezing…but just that one). A typical residential 6-inch metal vent moves 100 CFM. If you have a 3-ton AC and close off four vents, you just turned your 3-ton unit into a 2-ton unit. Thus, losing a third of the effectiveness (having a really dirty air filter can do the same thing).

Worst case scenario

Closing vents also causes the blower to slow down by restricting where the air can go. This can cause the evaporator coil to freeze, which will eventually destroy the compressor in the outdoor unit. Low airflow may also cause the heat exchanger to overheat, which could lead to a crack that potentially releases carbon monoxide into your house.

Final words

We suggest that you open your vents (but you probably figured that out by now), open your interior doors, change your air filters regularly, and let your HVAC unit work as it was intended. We go on many service calls that could have been avoided. At Mode, we are always happy to answer your questions and help you avoid costly repairs to your system.

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Thinking about buying HVAC equipment online? Here are some things you should know first.

When we go to a client’s home to quote an equipment replacement, here are the things we look at:

 

  1. What is the type and size of the equipment currently installed, if any?
  2. Why are we replacing the equipment? Is it because it is old and the client is being proactive (not usually the case)? Has the unit has been riddled with issues (if so, we need to find out what the issues have been)? Is the equipment not performing correctly (if so, why)? Is the unit just not worth fixing (we also need to know why)?
  3. Then we look at the details. Is the unit sized adequately? Are there any issues with the duct work? Was the current system applied and installed accurately (how do we rectify this)? Is the current system code compliant (if not, we must figure out how to make it so)?
  4. We also need to know what the client wants and expects. High efficiency? Reliability? Simplicity? We have to determine what brand will best suit their needs. We also have to figure out how to best adapt the existing duct system to work with the new higher efficiency equipment.
  5. Once we have answered all of these questions, we present an estimate based on those answers. We devise our recommendation from decades of experience, knowledge of the industry and its products, the latest in industry news and training…lots and lots of training.

 

When you buy online, they say you eliminate the “middle man,” but that is not true. You simply exchange one for another. You remove the person who has spent thousands of hours immersed in the industry; the person who will actually come to your home and make a customized suggestion; the person you can call on if there are issues; the person that has built relationships with local vendors; the person that will stand by his/her work; the person who has invested hundreds of thousands of dollars in his or her business; who has spent thousands of man hours on the job and in training to master his/her trade.

 

What you will get is an online retailer who will assign you a customer number and has no real qualifications other than shipping boxes. Admittedly, I have very little experience with shipping boxes.

Most, if not all, online retailers offer installation. They pay very little to the subcontractors they hire. Generally, you will end up with a new contractor; or one that is just “getting by”; or a contractor who relies on volume and not quality to pay the bills; or maybe a contractor with no customer service skills, so he relies on others for his/her customer base. Hopefully, the contractor they hire will have a business license and insurance, but that is not always the case. The online retailer will accept no responsibility for anything other than shipping the equipment to you or their contractor. Most reputable, well-established contractors will not install customer-provided equipment. It is often not worth the headaches involved.

 

Online retailers say that the units come with a factory warranty. This is true and false. Local equipment distributors depend on sales to contractors for their income. Anyone without a proper contractor’s license that attempts to obtain parts from a local vendor will be denied. Online retailers are the competition and the brick and mortar distributors are not going to help them – or their customers out. For warranty purposes, equipment serial numbers can be traced back to the original seller, despite what anyone tells you. The distributor will be able to tell where your equipment came from. So, even I, with my four Master Tradesman Licenses and my contractor’s license, will not be able to buy parts under warranty to fix your unit purchased from an online retailer. You, the buyer, not the contractor, will have to go to the original online seller to get the components you need for the repair. If the original equipment arrives damaged, you will have to contact the seller to get new equipment. Some manufacturers will go as far as to completely void the warranty if purchased online.

 

Unfortunately, many people find this out too late.

Yes, you can save money on the initial purchase, but the costs that you may incur later as a result of lost time, frustration and correcting shoddy workmanship will greatly overshadow any potential savings. In the end, as with most things, you get what you pay for. You can save a little money up front and risk potentially paying dearly in the future, or hire a reputable, local contractor to take care of everything for you and rest easy.

 

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