Most Likely Parts To Fail In A Commercial AC Unit And Why

With summer already here, there's just no living without air conditioning. While air conditioning units are built to be both efficient and reliable over long periods of time, the reality is that every machine and appliance suffers, and eventually succumbs, to wear and tear, if nothing else.

Rugged as they are, your air handlers and AC units are likely to continue working to keep the building cool in spite of this wear and tear, but will only do so at a reduced capacity -- resulting in higher energy costs for months before you even know to schedule a service call.

So what goes wrong in a commercial unit to cause it to fail and what can you do about it?

Let's take a look at the usual suspects...

Damaged AC Contactors and Capacitors

One of the most common problems a commercial air conditioning unit will face is the failure of contactors and capacitors. This is not surprising seeing as both parts deal with the flow of power throughout the unit, particularly the large amounts of energy required to start a cooling cycle.

Depending on the temperature outside, these will be anything between regular hot and very hot. This makes sense because the higher the temperature, the more electricity your AC unit needs to use to keep the building, property, and offices cool, and with the additional flow of electricity through these parts comes even more heat.

Naturally, this combination of heat and high-voltage makes them a common point-of-failure, but the unit itself will probably try to struggle on. You might notice clicking noises if you happen to be close enough to the unit to observe them, but you're more likely to notice a bad capacity or contactor as the unit has a harder and harder time switching on or staying on. Frequently, a stuttering or failed start will be followed immediately by what seems like a normal start -- this is not an indication that the problem has fixed itself, rather it's a pattern you'll come to see worsen if it's not addressed.

Luckily, repairing or replacing these components is not generally expensive or labor-intensive if the problem is caught quickly enough to prevent any further damage to the system. But as with any dangerous electrical work, it is best left to those who are skilled and trained to do it.

Failing Air Conditioning Compressors

The compressor in an AC unit is frequently referred to as its engine or heart with good reason -- it's a complex component largely responsible for the cool air we associate with our air handlers. An air conditioning unit without a compressor isn’t going to function, period.

There are also numerous reasons a compressor could start to fail, such as:

• Blocked suction lines

• Dirty coils

• Excess refrigerant

• Low refrigerant charge

• Wrong size of the suction line

• Contaminants and electrical issues

Due to the hidden complexity of the part, replacing a failing compressor may be the preference over repairing one, both in terms of cost and the longevity of the AC system as a whole. But depending on the exact cause of failure, the costs can still be pretty steep. In fact, compressor issues are a good reason to dig up the fine print on any warranties that still apply, and systems over ten years old (or using the aging R-22 refrigerant) may be better off replaced with a more reliable and energy-efficient unit.

Luckily, the compressor is a part that tends to give us a lot of warning. Like capacitor issues, clicking, clunking, or other noises and "hard start" issues can clue you in that there's a problem with the AC system. Somewhat easier to diagnose are issues of moisture leaks or pooling puddles around your HVAC system, which points more directly to issues with the compressor or its refrigerant. Warmer air or diminished air flow are also signs of a problem with the AC compressor. These signs and symptoms may start gradually, but will likely accelerate until the capacitor (and likely other components that become affected) ultimately fail.

AC Refrigerant Leakage

The problem with refrigerant leakage is that it can be difficult to locate where the leak is coming from. This is why a trained professional is needed to determine the source of a leak. There are various methods used to locate refrigerants leaks such as electronic leak detectors, dye test and isolation test.

Whatever the cause, refrigerant leakage issues can be difficult to find and repair. Be prepared to replace the refrigerant and possibly the refrigerant circuit if necessary.

If you think your building is suffering the effects of a troubled HVAC system, give us a call, and we'll get you squared away!

By Adam's Air Conditioning 15.12.2017
  • General