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System Trouble

Things To Check

System Trouble? Not Working? There are a few simple things you can check on your own before making that service call.
Like most things, heating and air conditioning equipment is much more complicated today than it was in the past. The good news is that sometimes when a system quits working, it can still be something simple.
Here are some things you can check and perhaps save yourself a service call. Also, take a look at our blog as we update it with new tips and tricks to achieve comfort and safety with your HVAC equipment
system troubleCOOLING ISSUES

The Summer months are typically when we get the most calls that can be solved without a service technician's help.

If your air conditioner seems to have quit working, here are some things you should check:

cooling issues

  1. Load Control (now called Power Manager). This is a voluntary program used by electric companies (Duke Energy offers this program) to help them manage the occasional extremely heavy demand for electricity. It helps them avoid having to build new power plants which in turn keeps our electric rates lower. How it works is that the utility company offers their customers a credit on their bill in exchange for allowing them to temporarily interrupt the power to their outdoor unit for a portion of each hour (in our experience it’s been for two hours or less.) Often no one notices because this peak demand typically occurs during the day while many people are at work or running errands (Duke promises to never run this program at night, on weekends or on holidays except in an emergency). But every now and again we get calls from customers who forgot that they signed up for the credit. If you’re not sure if you’re participating, check the following:If you’re not sure if you’re participating, here is something you can check. Check to see if the indoor unit is running but the outdoor unit is off. If it is, go outside and look for a small box with lights on it located near your outdoor unit. It’s probably hanging on your house. If it’s there, you are probably participating in this efficiency program. Wait for a couple hours and everything should return to normal.Unfortunately, there isn’t a way for Duke to let us know when the program is activated. We find out when we get the first phone call from a customer who describes the conditions above. At that point we’re able to pass the word along.
  2. The breaker has tripped. Check the electrical panel. Also check to make sure no GFIs are tripped.
  3. The filter is clogged. If you notice that the airflow has changed or is noisier than usual, check to see that the filters are clean. This includes any filters at the returns as well as at the unit itself.
  4. If you have a programmable thermostat, check which program is currently in effect. These phone calls are popular on holidays that fall on weekdays. People forget that their thermostat doesn’t know it’s a holiday and is running its usual weekday setback cycle.

Here is one thing that can't be fixed:

AIR CONDITIONERS HAVE A LIMIT ON HOW MUCH THEY CAN COOL ON EXTREMELY HOT DAYS. Air conditioners by design can not make a house colder than roughly 15 or 20 degrees below the outdoor temperature. If it is 95 degrees outside, it’s not possible for your air conditioner to get your house down to 68. There are a lot of mechanics, thermodynamics and other sciences behind why this is which you can look up if you’re interested. The best course of action when it’s a million degrees outside and your unit is running but not catching up is to wait until later in the day when temperature drops to see if the house starts getting cooler. If it doesn’t, then give us a call. If it does, you just saved yourself a service call.


The #1 call we get in the winter besides a no-heat call is to say the air coming out of the registers is colder than usual.

frosted coilsA couple other things happen at the same time: the fan blades on the outdoor unit quit spinning but the indoor unit stays on; the outdoor unit makes a whooshing noise and may even put off steam; and the auxiliary heat light comes on. All of these conditions are related to the same thing — your heat pump is going through a defrost cycle.

This is what's happening:

  • When it’s cold outside, the coil in the outdoor unit starts to frost over. A control mechanism senses this and reacts to prevent the motor from totally freezing up. It shuts the outdoor fan blades off, switches a valve called the reversing valve from heat to cool, and turns the strip heat on.
  • Your heat pump will now go into air conditioning mode. It will take heat from inside your house and use it to defrost the coil outside. To compensate for the fact that it’s going to have to blow cold air into your house for a little bit, the strip heat is turned on to try to warm the air up a little before it blows into your house. It will run like this for a few minutes (usually no more than 15 minutes) and then it will undo itself. The reversing valve will reverse again and make a whooshing noise, the blades in your outdoor unit will start to spin, and the strip heat will turn off. Everything is back to normal heat mode until it starts to freeze again.
  • If this goes on longer than 15 minutes or so, call us. There’s probably something more going on than the defrost cycle. Or if your outdoor unit looks like the one in the picture above, the defrost cycle has already lost the battle. Shut the system off and call us.