How to avoid an expensive HVAC repair

How to avoid an expensive HVAC repair 2

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How to avoid a costly service repair with

Mr. Mouse’s  Super-Cool HVAC Troubleshooting

Maintaining a comfortable temperature in your home is a big expense. Whether you rent or own there are definite pros to taking good care of your air conditioning units. When you live in a warmer climate, your A/C definitely gets some use.  Life expectancy for an A/C cooling system is much shorter in the southern half of the U.S. so regular maintenance can really prolong the life of your system. By maintaining your system, changing the filter monthly, and keeping your system set around 75 degrees you will notice a significant decrease in your power bill and a cooler home. On a side not, some other useful tips to save you money monthly on your power bill and keep you cooler are using ceiling fans and light blocking drapes. Nonetheless, eventually your A/C unit will give you some trouble. Waiting for a service tech to come is costly, inconvenient and a very uncomfortable wait. The good news is that a lot of the time you can solve the issue yourself. HVAC troubleshooting is fairly easy if you follow these steps.


  1. Double-check the setting on your thermostat. Make sure your HVAC thermostat is set on cool and is set several degrees below the room temperature read out. Move on to the next step.


  1. Is the outdoor unit coming on? This unit distributes the coolant to the indoor unit. If not proceed to number 5.



  1. Is your air handler turning on? This unit uses a fan to move the cooled air through the house. If not proceed to number 6.


  1. Are the outdoor and indoor units both turning on, but the system is not cooling? Proceed to number 6.


  1. Change the batteries in the wall thermostat. One of the most frustrating things to experience is paying a tech $100 to put new batteries into your thermostat. I have always found it to be a real flaw in A/C units that the cheapest battery operated piece, can shut down the whole system. However, it is what it is. So, change the batteries. Preferably, use a quality brand. If this did not solve your problem, move on to the next step.


  1. Check your filters. A dirty air filter will prevent your system from cooling at efficiency and make your A/C work so hard that sometimes it will even shut down. Changing your filters every month (especially if you have pets or smoke indoors), not only will save you from repairs it will lower your power bill significantly. Also, as a renter you could be violating terms of your lease by not changing the filters. This could leave you stuck sweating and with the repairs coming out of your pocket. A/C techs always know whether you have been changing your filters; Just like your dentist knows if you have been flossing. The $12 a year in filters pales to the horrible $800 servicing bill. That is not including the extra money you spend monthly on power bill from an overworked system. Therefore, changing the filters equals a lower monthly bill, a cooler home, and no sweating and waiting for a tech.
    ♦If your unit is completely off, and your filters are crazy dirty: replace the filter and wait at least an hour before trying to restart your system.
    ♦If your unit is not cooling the house and your filter is very dirty:Replace the filter, and turn the thermostat off. Now, turn the fan on the thermostat. Leaving only the fan on will help to thaw the frozen coils. Now let the fan run for at least an hour (preferably closer to 4 hours), before you try to restart.
    If your system is still not cooling or turning on proceed to the next step.


  1. Check your breaker box. If you have a trip, give it a flip. If nothing appears tripped, you can turn your system off at the thermostat and then, flip the indoor and outdoor unit breakers off and then back on (It is possible for the breaker not to trip all the way). Now turn the system back on and wait up to 10 minutes to see if the problem is resolved.
    ♦If the outdoor unit is still not turning on proceed to step 10.
    ♦If your indoor unit is still not coming on proceed to step 11.
    ♦If your system is still not cooling, proceed to the next step.


  1. Check if your system is locked up. There are a couple reasons for this. Especially, if you just went from heating your home to cooling suddenly. If the system is not cooling, turn everything completely off at the thermostat and for good measure flip the breakers off and back on. Now wait for 15 minutes. Turn the system back on. Wait until you hear the outside unit turn on and check if it is blowing cold. If your HVAC is blowing cold air, pat yourself on the back. If not, proceed to the next step.


  1. While the outside unit is on, is the fan running? When the fan is running, it should be noticeably warmer than the temperature outside. Place your hand above the fan and check for a temperature difference. On a side note if the fan is not moving but you can hear that the unit is on, turn the unit off and check for any obstructions preventing the fan from moving.
    ♦If there are no obstructions, go to step 14.
    ♦If the fan is running with no temperature difference, please continue to the next steps.


  1. Inspect around the outdoor unit for any damaged wires. There should be a bunch of wires bundled together coming from the house to the outdoor unit. Often animals will chew on the wires or they can be damaged during lawn maintenance. If you found a damaged wire, flip the breakers off. Depending on your comfort level with a repair like this now might be the time to call in a favor from a handy family member or friend. Alternatively, you could have your HVAC tech come handle the task for a fee. If it is possible, it is always better to try to keep spliced wires out of the elements. Sometimes, when an HVAC unit was originally wired, the techs are considerate enough to leave a significant amount of slack in the wire.  You can very gently pull on your damaged wire to see if there is enough slack to wire it back in to the unit. Otherwise, measure how much wire you will need and then cut a small piece of the damaged wire to bring with you to the hardware store. Be sure to purchase extra length wire than is actually needed. After making doubly sure that the power to the system is still off, replace the damaged wire by splicing the colored wires together. Be sure to use wire nuts on each connected wire and then wrap in electrical tape. There are many great YouTube videos that can walk you through this process. It is a common problem and as long as you make sure the power is off, I think a beginner can manage this repair.If there are no damaged wires, please proceed to the next step.


  1. Check the safety switch and condensate line. Most units have an overflow safety switch. The purpose of this is, when the coolant moves through your system it is super cold and it condensates. That condensation is collected into an overflow pan inside the air handler, and then it flows into a pipe that eventually leads out of the house to drain. Usually, there are two pipes the one that travels out of the house to drain, and the secondary PVC pipe that will house the safety switch. Sometimes there is only one pvc pipe to drain the condensation and the safety switch is installed by reworking the pvc. While this is not the norm, the idea still applies. If there is a clog somewhere, when the water begins to overfill, the safety switch floats up and turns the system off. This protects your system from any damage and prevents water flooding inside your home. It is usually easy to spot. Once you find the safety switch, gently lift it up out of the pipe. If your unit comes on after lifting it up you have solved half the problem. Now, cut the power to the system just to be extra safe. Using a shop vac, you will need to suction out the water in the line that is causing the switch to float. You can suction the water out either through the over flow pan or the PVC pipe itself.  Now, there is some controversy as to what the better cleaner is for your condensate line, vinegar or bleach. I personally prefer vinegar followed with a hot water rinse, because bleach is so aggressive and the smell is so overwhelming. Pour a cup of vinegar and allow it to sit for about 15 minutes. Using your shop vac again, you will now go to the outside condensate drain. It should be very close to your outdoor unit and dripping vinegar by now. Try to get a good seal around the PVC pipe and the shop vac. Once you get a good seal turn your shop vac on, and allow it to run for several minutes pulling all the gunk and vinegar out of your line. Now, I like to add some very hot water (roughly 4 cups) to flush the vinegar out just for good measure. This task is much easier with one person using the shop vac while the other slowly pours the hot water in the line.  Use the shop vac on the outside drain again to pull out the rest of the water.  Now, restart your system. Sometimes you may have to wait up to 10 minutes for everything to turn back on. If this solved your problem, be sure to give yourself a pat on the back and a firm handshake.If your system is still not turning on, proceed through the rest of the steps.

AC disconnect box for HVAC troubleshooting

  1. If your outdoor unit is still not turning on you can check the disconnect near the unit. However, this step is really best left to someone who is comfortable with repairs involving electricity. This can be very dangerous if you are not very cautious and at least somewhat experienced. Electrocution is not like in the cartoons. The disconnect is what houses your fuses that protect your condenser.  The disconnect is easy to spot, you will see a small box near the outside unit.There’s two ways to check your fuses. The first and the easiest way to check your fuses is with a voltmeter and the second is to just swap the fuses.  When you open the disconnect box you will see a pull out cartridge and an additional cover that needs to be removed to access the line(in) and load(out) wires. Typically, what you will see is two ‘line’ wire (incoming wires) and, two load wires (outgoing wires). Now, using your voltmeter you will test the line and load wires: Using the voltmeter, we will take the red (+) to the black line wire and the black (-) to the white line wire. The voltmeter should now read in the 220 range. If the voltmeter reads nothing then this means there may be an electrical problem. In other words, no power is coming in. If it reads in the range of 220 volts your good to go. Now, test the load wires. Put the red (+) lead to the black load wire and the black (-) lead to the white load wire. If the voltmeter reads in the range of 220 volts, the fuses are fine but if it reads flat, the fuses need to be replaced. If this is the case, you may have just found your problem. Pull out the cartridge and replace the fuses and hopefully your good to go. If you do not have a voltmeter, you can try the second method of swapping the fuses. Make sure the power is off at the breaker box, pull out the cartridge, replace the fuses with new ones, and then see if it works. Fuses are cheap and if it does not solve the problem chances are you may need them one day anyway.


  1. Are both units still running, but still not cooling? Now you will need to call a technician but before you do first evaluate your lines and arm yourself with information. The more information you have when you call them the better prepared they will be to service your system. On your outdoor unit, you have two lines. One line is bigger and wrapped in insulating foam. The other line is smaller. Generally, the bigger line is located below the smaller one. The small line is referred to as your liquid line and the bigger line is called the suction line. When your system is running properly, the small line will be hot to the touch and the larger line will be quite cold. The coolant pushes through the liquid line with a lot of pressure, which increases the temperature. As the coolant changes state, and goes through the indoor unit, it is sucked back through the suction line. This leaves the suction line very cold and the reason it is usually insulated.  If you see that your small liquid line is cold or icing, inform your HVAC tech so that they know where to start troubleshooting and get your home cooler faster.


  1. Is the outdoor unit turning on? But the fan is not moving. In this situation, what you should do almost seems made up. Take a long sturdy stick that is thin enough to fit through the grate. Now, give the fan blade a good push with the stick and pull the stick out quickly. If the fan starts spinning after the stick jump-start then you need to replace the capacitor. The capacitor is a relatively easy fix. Mainly what you will do is turn the power off at the breaker. Open the side panel on the outdoor unit. Now, you will see a medium sized cylinder with wires running to it. Take photos of the wires to reference later. Then find any serial numbers for a replacement part. When you acquire a new capacitor, you will simply wire it the same as the old capacitor. If you feel that this repair is out of your comfort realm, please contact a technician.If none of the above helped to solve your problem, unfortunately it’s time to call the HVAC technician. However, at the very least you can tell them what you tried so they know where to start to get you cooled off quicker.





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2 thoughts on “How to avoid an expensive HVAC repair

  • How to avoid an expensive HVAC repair Anonymous

    This is extremely helpful! I am glad that I found your website. Simply switching the batteries in my Thermostat saved me a service call to the A/C guy