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How To Keep Your A/C From Giving You The Cold Shoulder

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It's not out of the ordinary to see a little frost forming on your air conditioning system. When that light dusting turns into slabs of ice, however, it can pose serious problems for your A/C system. Excess frost and ice buildup can prevent your A/C from cooling effectively, plus it could lead to long-term damage to your A/C system's various components. The following guide shows how you can break the ice and thaw out a frosty A/C unit.

Reasons for Excess Frost and Ice on Your A/C

There are plenty of reasons why your A/C system might freeze over. One reason involves poor air flow to the evaporator coil, which is tasked with pulling latent heat out of the air that passes through it. Under normal circumstances, temperatures at the evaporator coil are kept just above the freezing point, but poor air flow can cause condensed moisture to freeze on the coil and slowly build up until it becomes a thick sheet of ice.

Your A/C system can also freeze over if it's low on refrigerant. When this happens, the effect is the same as deliberately emptying a can of compressed air until it's empty -- as pressures within the can drops, so does its surface temperature. This also holds true for an evaporator or condenser coil that's low on refrigerant. A drop in coil surface temperatures can cause ice to form on its surface.

Mechanical malfunctions such as a failed expansion valve or compressor seal can also cause an A/C system's coils to freeze over. Last but not least, operating your A/C system under low outdoor temperatures, such as during the late-night and early-morning hours, can also cause ice issues.

Breaking Your A/C Out of the Deep Freeze

When it comes to removing ice from your A/C system, the last thing you want to do is chisel or scrape the ice off of the evaporator or condenser coils. The coils are rather fragile, and putting sharp tools against these surfaces could result in serious damage to those components and an expensive repair bill, to boot. Instead, your best bet is to leave your A/C system off for a few hours and wait until the ice melts. You could use a hair dryer to help speed up the process somewhat, but you'll have to be careful to not get any of the A/C components too hot.

After thawing out your A/C system, you can do the following to check and pinpoint the cause of the recent freeze-up:

  • Check the air filter and make sure it isn't completely clogged with dust and debris. Ideally, you should have your air filter changed on a monthly basis to promote better indoor air quality and prevent freeze-ups from happening.
  • Make sure the return air vent isn't blocked by furniture, boxes or any other objects that could potentially obstruct the vent.
  • Closely monitor the refrigerant lines, as well as the evaporator and condenser coil, for any signs of leaks. You should also check the compressor and make sure it's not leaking any oil or refrigerant.
  • Give your condenser coil a thorough cleaning by vacuuming and later rinsing the outdoor cabinet. Also make sure there's no vegetation or other obstructions around the bottom of the cabinet.
  • Remove any and all debris form the evaporator coil. You should also check the coil for any signs of mold growth and clean the coil accordingly.

If you're still having problems after checking or completing the above steps, have an HVAC technician from a company like Affordable Plumbing & Heat measure the amount of refrigerant that's currently in the A/C system. Checking the refrigerant requires specialized tools and training, so you wouldn't want to handle this step on your own.