Air conditioning FAQ

Air Conditioning FAQ 2026

Air Conditioning FAQ 2026 

  • Is air conditioner cleaning and tune-up necessary?  
  • Why is my central air conditioner not cooling, not blowing cold air?
  • Why is my air conditioning freezing up?
  • Why is my air conditioning making a loud noise?

 

Is Cleaning the AC Unit Necessary?

Manufacturers know that an HVAC system can degrade 3% per year. When components start to degrade, the system works harder to produce the same result. This is one reason manufacturers may void the warranty if the system is not maintained. 

Shine a light on dirty threats, which are the #1 cause of breakdowns and wasted energy.

  1. An annual AC safety check warns you if your HVAC system has potential weaknesses or can make you sick.
  2. A tune-up improves energy efficiency and air quality and helps avoid expensive emergency repairs.
  3. A knowledgeable, kind-of-a-neat-freak will clean, adjust, calibrate, and reset the finer points to factory specs. Improves comfort, lowers utility bills, and extends equipment life.
  4. Annual HVAC maintenance plus duct cleaning keeps you healthy and worry-free by cleaning bacteria, mold, dust mites, pollens, VOC’s, and pollutants from your indoor air system.

When compared to what can go wrong or even close your business, it’s clear that an HVAC maintenance plan from a trusted professional is well worth the investment. Learn what a PDM AC tune-up includes.  

 

Why Is My Central Air Conditioner Not Cooling, Not Blowing Cold Air, Not Kicking On?

  1. The thermostat is a common problem. Make sure power is on (replace batteries?) and that the fan is set on Auto and Cool? Set 5 degrees lower than the room temperature.
  2. A dirty furnace air filter can reduce air flow by 60% and affect the evaporator coil. Poor air flow can cause ice buildup on the refrigerant line. Turn off the unit if you see ice buildup on the refrigerant lines. 
  3. Clogged condensation drain pipe. Your A/C removes humidity from the air and drains it out through a pipe. Algae, even mold, can block the drain pipe and shut down the cooling.
  4. Dirty outdoor compressor or indoor evaporator coils. Dirt, leaves, spiders, or mold can reduce the cold air. Clean both coils. Do not bend the outdoor fins when cleaning. Use a soft brush or a gentle water hose spray to clean the outdoor unit. If the outdoor condenser fins are bent, you may need a special fin straightening tool.  
  5. Electrical fault. Why is the outside condensing unit on, but the fan isn’t moving or is moving slowly? It can be a faulty outdoor condenser fan motor or a run capacitor switch. If the condenser is not working at all, check the dual run capacitor or the contractor. Check the air handler float safety switch, the drain line, and the electrical breaker panel for any tripped circuits.
  6. Low refrigerant. A/C won’t cool on a hot day, but it works on cooler days, which can mean low refrigerant. Call PDM for professional help today.

 

Why Is My Air Conditioning Freezing Up?

The A/C refrigerant line is covered in ice, which seems crazy on a hot day. Freezing up generally has to do with blocked or low air flow, over-use, broken parts, or refrigerant problems. Chances are, ice forms around the evaporator coil inside, preventing the a/c system from working.

  1. DO THIS NOW. Turn the thermostat COOL system OFF and turn the FAN ON to help defrost the unit. This helps to defrost the coil and prevent damage to the expensive compressor. After the ice melts, you can turn on the AC again. If ice reappears, turn off the AC and call the PDM Comfort Team.
  2. Check the furnace air filter. Does it look like a gray furry cat? You may find the problem is simply due to a dirty filter, which can block over 60 percent of the air flow. Replace the filter or remove the dirty filter and see if the cooling returns.
  3. Are the duct air registers and return line not blocked by drapes or furniture?
  4. If the problem persists, contact PDM Cooling before this sticky situation worsens. And if you haven’t had air conditioning maintenance, it’s time to act. You’ll feel better.

 

Why Is My Air Conditioner Making A Noise?

Listening to a specific sound can provide a clue about what’s wrong with your HVAC system. Common causes of air conditioner noise include damaged ducts, clogged air filters, fan problems, coil damage, loose parts, motor bearings and belts, and even electrical issues.

 

Squeaking, Squealing, or Screeching Noise

    • High-pitched noises can be compressor and fan motor problems. 
    • Bearings, slipped or damaged blower belts can be the problem.

 

Loud Buzzing Noise

    • Usually an electrical problem. 
    • A clicking sound can mean your system’s relays or contractors are failing. 
    • Call PDM to fix this type of air conditioner noise problem.

 

Humming Noise

    • A rattling or humming fan likely needs a good cleaning. 
    • A worn-out part in the fan, problems within the fan motor, or bent or shifted blades could also cause this air conditioner noise.

 

Banging, Whining, or Whistling Noise Could Signal Airflow Problems

    • A duct may be too small or damaged, and make a whistling noise. 
    • It could be “oil-canning,” where the ductwork flexes as pressure changes. Need to find the weak duct area and reinforce. 
    • Check for the clogged furnace air filter. Poor airflow can cause air conditioning noise and make it difficult to breathe.

 

Hissing Noise from A/C

    • It could be caused by a refrigerant leak. If that’s the case, you may also notice that your system is running more often and not cooling as well. It’s time to call in PDM for answers. 
    • Refrigerant leaks can be caused by poor maintenance. Coils that are not regularly cleaned corrode, leading to small holes and cracks through which refrigerant leaks. You can prevent this problem by getting a preventative HVAC maintenance plan.

 

Shaking and Rattling Noise

    • Loose air conditioner parts related to movement are a common cause. Motors can come loose, and ducts too.
    • Are screws in your A/C panels shaking loose?
    • Is your air conditioner unit secured to its concrete footing? A mounting screw has come loose?

 

AC Making a Constant Running Noise

    • Bent outdoor coil fins can produce a humming sound. If clogged with dirt, your A/C wastes energy and ends up running constantly as it struggles to reach the set temperature. If you ignore this problem, it will cause a breakdown.
    • Look at your outside condenser unit. It is not unusual for twigs and other debris to get stuck in the condenser unit’s fan. Make sure the area is swept clean of dirt and debris. Cut back any bushes a few feet from the unit.

 

Answering A/C FAQ Since 1885

Got air conditioning FAQ? Ask a knowledgeable, kind-of-a-neat-freak PDM Cooling technician. PDM will get you back to normal fast. Contact the oldest cooling specialist in the greater Joliet, Plainfield, New Lenox, Lockport, Homer Glen, Bolingbrook, IL area.  Call 815-390-7095.

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