The compressor is the heart of your air conditioner, providing the pressure needed to allow the refrigerant to transfer heat out of your house. A failing compressor is a major problem, so you want to be able to troubleshoot it as soon as possible. Here is a look at how homeowners can address compressor issues.
What the Compressor Should Operate Like
It is important to understand what the baseline for normal AC operation is. An AC compressor should have a steady hum during operation. It might be a little noisy when winding up or down, but once it’s in mid-cycle the compressor should operate at about 40 to 60 dB. This is about as loud as your dishwasher sounds when you’re standing near it.
Also, there should be no grinding and squealing sounds. If you hear metallic or mechanical noises besides a steady hum, it is best to turn the AC off entirely.
The unit should be relatively warm to the touch. However, it should not be hot. Overheating is another sign that you might want to turn the system off.
Refrigerant Loss
There could also be a loss of refrigerant that’s making the compressor struggle. That can be a problem because extended operation in this condition could eventually take out the compressor.
Fortunately, our technicians can usually check the AC lines for leaks and then recharge the refrigerant. The difference between replacing a compressor versus recharging the refrigerant is likely thousands versus hundreds of dollars.
A refrigerant loss can also cause hissing sounds. Even a small loss can quickly affect pressurization and performance.
Cycling
System cycles should take about 15 to 20 minutes. On very hot days, this could push as high as 30 minutes. Longer cycles are a sign the system is struggling but still working, with one possibility being a slowly failing compressor. Shorter cycles, such as five to 10 minutes, could indicate that a shutoff is triggering inside the AC. If a compressor is overheating, it can trigger a shutoff.
The time between cycles should be about five to 10 minutes. However, it could wait longer in milder weather.
Proper Sizing
An AC system should be a good fit for a house based on capacity, which is normally measured in tons or BTUs. Household AC units usually go from 1.7 to 5 tons or 20,000 to 60,000 BTUs.
Roughly speaking, 20,000 BTUs or 1.7 tons should cool about 1,000 square feet of house. This assumes the house has eight- or -nine-foot ceilings. Houses with south-facing exposures may absorb more sun and require perhaps 10% more cooling capacity.
Running an undersized AC in a larger house could strain the compressor. While oversized units aren’t particularly efficient, the difference doesn’t normally cause a problem.
Visible Signs of Compressor Trouble
The most visible sign of compressor trouble is accumulated ice on the condenser coils on the outside unit. If the system is struggling to exchange heat, ice forms. The issue could be as simple as cleaning the coils. It also could be a sign that the system is running low on refrigerant or that the compressor can’t keep up.
You should also check the filter. If the filter is dirty, the system may be struggling to draw and push air. Once more, this strains the compressor. If you see evidence of a dirty filter, replace the filter and see if the compressor issues get better. Also, make sure the right type of filter is in place. If a unit doesn’t support using a HEPA filter, having one could choke its airflow.
Refrigerant leaks also leave visible signs in many cases. AC refrigerant includes lubricants to keep internal parts moving well. If there’s a leak, these lubricants can leave an oily residue. You might see a patch of stained concrete under a fitting that has loosened, for example.
Smells
A burnt smell is a notable sign that something may be wrong with the compressor. This is another instance where you should shut the system down immediately and call an AC repair professional. That is especially the case if there’s any smoke.
Musty smells could also indicate a failing compressor. Especially if you’ve already replaced the air filter, a musty smell may be a sign that the system isn’t drying the air enough. This causes mold growth that leads to a distinctly basement-like smell.
Electrical Issues
Presuming the circuit for the HVAC is properly sized, usually between 20 and 60 amps, the AC should cause no electrical issues. If the circuit breaker regularly trips, then the compressor could be drawing too much power. Some compressors draw more power as they fail, leading to breakers tripping.
Sparking or buzzing coming from the unit is always bad. You also don’t want to see anything like this near the electrical panel of your home.
Troubleshooting
As long as there are no critical signs of trouble that call for an immediate shutdown, you can do some basic troubleshooting. Set the thermostat to five degrees below the current air temperature in your house. Wait five minutes to see if the system kicks on. Note whether the outdoor unit starts running.
Check the circuit breaker. If it has tripped, reset it once. If it trips again, then it’s time to ask one of our technicians for help.
If the AC is running, check the vents for airflow by holding your hand about a half-foot away. If you feel weak airflow, there’s a good chance the compressor is straining. If there’s good airflow but little cooling, the issue is more likely related to refrigerant.
Note the noise level and steadiness during AC operation. If it seems to be normal and there’s cool air, then there might not be an issue. If you’re getting cool air but hearing loud noises, then tell us what you’re noticing. It is better to be a little too suspicious than to let a problem go.
Also, note the length of the cycle. If the cycle time is normal and there are no other issues, then your system is likely in the clear.
Finally, check the exterior unit. Verify that it’s free of debris and ice. Make sure no plants are growing within three feet of the unit. Also, make sure no large objects, such as your lawn mower, are nearby.
When to Call Our Technicians
If you have exhausted all possible options and still suspect something’s wrong, then it’s time to schedule one of our technicians. Also, if you’ve determined there’s a refrigerant loss, then that is a job for us because homeowners can’t legally handle refrigerant. Similarly, accessing components like the compressor could void your system’s warranty. There are also frostbite risks associated with refrigerant, and the compressor’s high voltage can be dangerous.
O'Brien Heating & Air Conditioning is proud to have provided air conditioning services for Drexel Hill, PA and the surrounding communities for more than 70 years. We are a BBB-accredited business with an A+ rating, and our company is a Lennox Premier Dealer. We work on all HVAC models, too. Our technicians can quickly perform HVAC installations, repairs, and maintenance.
If you’re worried that your AC compressor might be failing, trust the technicians that many Drexel Hill residents rely on and contact O'Brien Heating & Air Conditioning today.
