Noisy air-conditioning unit shouldn’t be ignored

Many of us fired up our air conditioners for the first time this week. That chilled air assures us that we’ll get through another three-digit summer. What’s disturbing is when our air conditioner suddenly makes strange noises.

The types of noises an HVAC system (heating, ventilation, and air conditioning) makes can tell what the problem is. For example, a professional can know if there is a buzzing noise, if it is an electrical problem, or a gurgling / bubbling noise, if it is a refrigerant leak or a clogged condensate drain line.

Some HVAC noises can be downright alarming, and with good reason. A very loud high-pitched sound may indicate internal pressure building up in the compressor. Typically a sensor will cause the unit to shut down if the pressure exceeds a certain level. If there is no sensor, or if it is faulty, the pressure can rise to a very dangerous level. If your air conditioner is making these kinds of screaming noises, turn off your air conditioning immediately and call a professional.

Keep in mind that if your HVAC unit shuts down suddenly, it is probably for good reason and this safety mechanism is doing its job.

Aside from the screaming described here, take a moment to do a little research if your air conditioner starts making a strange noise before turning on the big guns. As an advocate of DIY enthusiasts, I encourage you to take this step. Sometimes a small repair and regular maintenance can save you a service visit.

Here are general steps to perform your own remote HVAC inspection and maintenance.

To clean and maintain the outdoor unit (condenser and compressor):

Warning: Power to the entire HVAC system must be turned off.

Switch off the unit at the thermostat and at the circuit breaker in the main service panel, or at the dedicated smaller electrical box near the unit.

▶ Remove dirt in and around the device. Your device should have a clearance of 2 feet around it and 5 feet above it. Remove any vegetation, leaves, etc. To access the inside of the unit, use a screwdriver and wrench to remove the fan housing on top of the unit. Vacuum or remove all debris by hand. Wipe the fan blades with a damp cloth.

▶ Clean and straighten the fins. Gently vacuum the fins in an up and down motion. Fins bend easily so don’t run over them. Spray a fin foam cleaner; let it sit according to the instructions. Rinse gently with a garden hose. Do not spray on the fan motor. The fins must be straight to maintain good airflow. Use a fin straightening tool (spiral fin brush) to fix them. Foam fin cleaners are available at our local hardware stores, but the fin brush must be ordered (less than $ 10).

▶ Check that your external HVAC unit is level. Like foundations, they can shift over time. A condenser that is not level can cause a compressor to age prematurely. If unit is not level, use rot resistant shims to raise as needed.

▶ Check whether the condensate line is dripping. This pipe should run out and water should drip out when you use your air conditioner. If it doesn’t drip, it won’t drain. Remove any blockages that have formed in the tube from algae or debris.

When you have completed your HVAC maintenance on the outside, turn the unit back on, set the thermostat to cool, and listen for strange noises.

For easy interior HVAC maintenance:

▶ Inspect the ventilation openings for dirt (mold, insects or rodents). Remove the cover and examine the inside with a flashlight.

▶ Replace filters at least twice a year, but more often in dusty environments or if someone has allergies or respiratory problems.

▶ Inspect pipework. Look for obvious cracks, examine the joints, and check all duct tape. Switch on the appliance at full power and run your damp hand over these areas to feel if there are any leaks.

Should any of these checks or maintenance scratch your head in confusion or block your ears from noise, contact an HVAC repair service as soon as possible. Keep calm and carry on.

Norma Vally is a seasoned home improvement veteran; her career spanned four seasons as the host of the Discovery Home Channel’s Emmy-nominated series “Toolbelt Diva”. As a columnist and author, Vally divides her time in Southern Nevada, Los Angeles and New York City. Follow her on Facebook at Norma Vally “Toolbelt Diva” and visit her at Email [email protected]

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