Why Isn’t my AC Working!?

It’s spring, mother nature is keeping you in the eighties or nighties already. Your office is unbearable. The intern has somehow duct taped ice bags to his back and ruined his office chair in the pursuit of not melting. It’s time to turn on the AC and nothing happens. Kronk throws the lever and the air blasting in is hotter than the pavement Dave the Intern cooked his lunch on. What happened?

 

The Little Problems

There can be a million things wrong with your AC. Some issues are catastrophic and very expensive to repair as our lead sales guy Scott learned the hard way just a few weeks ago. Other issues are smaller, cheaper, and merely annoying.

Did you Turn on the Power?

Most central cooling systems have a dedicated circuit breaker to turn them on and shut them off for maintenance and long-term deactivation such as through the winter. Turning off this breaker in the fall ensures your air conditioner physically cannot be engaged in the winter and accidentally damage itself.

Depending on your situation, you may not have known this switch exists or your building maintenance team just hasn’t turned it on yet. If you enable your air conditioner in your thermostat, crank down the temperature, and nothing happens, this is the first thing to check. If you know where the breaker for your AC is, check on it. If you don’t, contact your building maintenance team and they’ll check on it.

It’s ON, but HOT?!

The issue isn’t electrical, it’s worse than that. Hot air is coming out. There is zero cooling going on, your office has no chill. There are a few minor problems this could be before we start running into big-ticket repairs. There could be a leak, a bad fan, a bad fuse, or a bad thermostat. These are all things that usually only cost a few hundred dollars at the worst to repair.

The big, bad monster in the air conditioner is a leak. After a long winter, it’s possible that the freezing and thawing has broken a connection or a fitting somewhere in the air conditioner. The refrigerant inside is a gas, it’s like oxygen, something that just floats in the air. When a leak occurs, all the refrigerant is let out and there is literally nothing inside the air conditioner to actually do the cooling. Repairing a refrigerant leak is a two part process. The leak must be found and repaired with a new fitting or pipe and the system must be recharged with a fresh load of refrigerant. This problem is extremely common in used cars, where cheap dealers will recharge the air conditioner without fixing the leak.

Fans are the second big issue and these can have two types of problems. Some air conditioners drive their fans with a belt rather than directly off the motor. This allows for cheap gear reduction between the motor and fan without having to actually use expensive gears. Belts however, are extremely prone to wear and tear. Over time and changing seasons, belts will wear out. Typically the large fan in the condensing coil is the one driven by a belt. When this belt fails, the fan doesn’t move and there’s no way for the condensor to quickly dissipate heat. The air conditioner is crippled until the belt is replaced.

Otherwise, it’s possible for a fan motor or fan blade to fail entirely. This can be from wear and tear, weathering, or even dirty ear tearing up the blade surface. This can effect any fan or motor, including those inside the building to push cold air through the duct work. These parts can cost anywhere from $50 to a few hundred dollars, but they’re usually on the cheaper side.

Electrical issues can also develop. A thunder storm and a power surge could blow out a fuse in the air conditioner or a small electrical short could form after a mouse nibbles the wrong wire for an early spring snack. In an ideal world, the fuse will self destruct before any harm comes to the air conditioner. Your contractor can probe the inside, find the issue, and replace the shorted component or patch the shorted wires within a few hours to get things back on track. If a fuse has failed, NEVER just replace it. Fuses generally fail as a symptom of further damage elsewhere in the system.

Finally, your thermostat could have died. This is the issue I had last fall when we switched on our heating system. We flipped the switch and nothing happened. After some button mashing the furnace roared to life and tried to melt us out of the house. The same issue can occur with air conditioning. The thermostat may refuse to turn on the AC or it may call for it at all the wrong times. This happens due to a failure inside the thermostat, generally a relay has finally failed and will not actuate. Relays are mechanical switches, over time they can fail and become seized in the on or off position. Once you’ve confirmed the issue is in the thermostat, they’re easy enough to replace for an experienced DIY-er or any contractor.

 

What About the Big Issues?

Stay tuned for that in an upcoming blog. There are a few big problems that can go wrong with an air conditioner too. When something big gives in, you’re faced with the question of fixing it and moving on, or replacing the whole system to stave off future hardware failures.

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