Six Vulnerabilities of Air Conditioning Systems

AC Maintenance

1. Dirty or Leaky or Frozen Evaporator Coils

The coils inside the central air system works with the condenser (the outside unit) to provide cold air by absorbing the warm air coming through it. This is what actually cools the air that gets circulated throughout the building. When the coils get dirty, they must work harder to absorb the warm air and thereby produces less cold air. If they are restricted too much too long a layer of ice collects around the pipes. This can happen on both inside and outside pipes. It may not seem logical but if the pipes are frozen, cool air will not be circulated through the system to the rest of the house.

If there are leaks in the line that transfers the refrigerant (or Freon), the smaller amount left in the lines causes the system to work harder and break down sooner. When the leaks of Freon line first appear it may result in a minor repair. But the older the system gets, the more leaks appear, and become much more costly to repair. This leads to replacement of at least the coil, which usually is buried inside the middle of the system, making it costly to replace. And if the coil is older than the rest of the system, then there is usually the unwanted decision of whether to pay more to replace just that part as opposed to buying a whole new system.

 One quick background note on Refrigerant:

R-12 is the old type used in previous systems, but no longer allowed.

R-22 which is commonly called FREON is used in many systems, especially in transitional situations and much safer to the environment.

R-32 is newer and better than R-22.

R-410A is the newest type and sometimes call Puron.

R-134 is another type and is used in refrigerators.

2. Dirty Condenser Coils

The condenser is the outside unit that works to expel heat outside that was absorbed from inside the building. If these coils are dirty, the system must work harder to transfer out the heat. This will also cause failure in both the outside and inside units. The worst culprits are a collection of dirt, trash, leaves, branches, and insect piles.

3. The Blower Fan

This fan works all year to circulate air throughout the building. It works very hard all the time the system is running. The many parts to this piece, including motor, blades, stem, bearings, belt, all must stay clean, lubricated, and unobstructed. If it fails, it also affects the compressor outside. There is also a fan outside on the compressor unit that runs anytime the cooler part of the system is running.

 4. Duct System

This is important to allow air to flow freely throughout the building for satisfactory cooling or heating. Any number of things may restrict or divert the flow of air including holes, breaks, or build up of dust and debris. The worst things that may happen would be rodents that cause holes, a person moving around the attic accidentally crush or move the ducting, or poor installation and/or repair. Sometimes it is as simple as some of the binding tape coming loose.

5. Thermostat

These come in many different shapes, sizes and functionality. Sometimes the old and new units may need to be re-calibrated. Often they can be set up inefficiently by lack of knowledge of the users. Other times with the new circuit boards there may be part of it that still appears to work but less efficiently. I have even seen where the wiring was loose or broken and shorting out intermittently. Usually if there is an unknown factor causing a problem, it is best to replace the thermostat.

6. Drains

The run off moisture that collects as the system cools the air is the cause of a most elusive problem. First, it collects link and silt. Second, it must always be eliminated properly. Over time the flow of slightly dirty water inside the system can clog either the primary drain, the pipes carrying it, or even the joint fitting that it escapes through from the pan underneath the coil. Most efficient systems include a secondary drain line that comes into service if the primary drain becomes clogged. This secondary drain is either installed with an alarm or device that automatically shuts down the system, or a visible outlet channeled outside where the occupant can see it and alert the AC tech (if they are savvy to the situation).

The worst problems are leaks in the Freon (refrigerant) line, dirty coils, and clogged drain pipes. The harder the system must work for any part of it, the sooner it will wear out.

The easiest preventions are:

- Yearly cleaning of the coils and drains, as well as inspect ducts and repair holes

- Clear plant growth and debris from around the outside unit on a quarterly basis

- Faithfully replace Air Filters every month