HVAC Maintenance for DIYers
Proper maintenance of your heating, ventilation, and air conditioning systems can significantly reduce costs, improve comfort levels, and extend equipment life. Despite all that, many people fail to even perform a simple check a couple times a year, just to make sure everything is working right. HVAC components and systems require a little attention every so often, just to avoid the performance degradation that is a constant problem. More than comfort, though, a lot of people are worried about the rising costs of energy. Even without the increasing fuel costs, a normal HVAC system is already responsible for half of the average home energy bill. With no apparent respite from these increasing costs, a few simple maintenance procedures can help you control the amount of energy you use while still keeping the house nice and comfortable.
Chapter 1: Getting to Know Your HVAC System How It Works There are a lot of components in a modern HVAC system (over a hundred, easily), but the basics behind how they work haven t really changed in decades. It s all about pushing and pulling air from one place to the other in order to create the most comfortable indoor environment. And once you understand a little more about how it works, you ll be able to identify any problems (or potential problems) a lot easier. Heating There can be a lot of variation in heating systems. Some homes use gas while others use oil, but whatever the fuel or heating
element, the goal is the same: draw cool air in through the ductwork, heat it, and then return it into the home at the desired temperature. There are two basic types of heaters. One uses a heat pump, and the other makes use of a furnace and central air system. The heat pump is generally considered more efficient than furnaces that are used for the same basic job, but the furnace/ centralized system will probably last longer. There are also some hybrid systems that can determine the temperatures at which it will be the most economical to use the heat pump or the furnace and switches between the two as necessary. Ventilation System This includes the return and supply vents, ductwork, fillers, and circulation fans. The fan pulls air from inside the house through the return vents and then, in a forced air system, sends it back out once it has run over the heating element or cooling components.
Once that is done, the refrigerant is seeped into the indoor evaporator coil where it can expand once again, reducing the pressure on it and, simultaneously, bringing the boiling point back down. This turns the liquid back into a gas, which absorbs the heat from the air around it. This air, that is now much cooler, is pushed into the home by the fan. Then, the low-pressure gas heads back to the compressor to start the process all over again. Cooling Most HVAC systems are split systems, which means they have both an outdoor compressor/condenser and an indoor evaporator coil. The two halves are connected by copper tubing, through which the refrigerant runs. The refrigerant is a chemical that can go from liquid to gaseous states even at moderate temperatures. It begins the cooling process in the compressor side of the system as a cool, low-pressure gas. The compressor s job is to compact the refrigerant into a hot, high-pressured gas, which is then sent through the condenser where it turns into a cooler, high-pressure liquid as the fan blows the excess heat away from the home. Why It s Important Understanding a little more about the ins and outs of your HVAC system will help you perform the necessary maintenance and spot any potential problems. As you keep up with those maintenance requirements and carefully manage your system, you ll start to see a lot of benefits, including: Lower energy bills Longer equipment life Cleaner, healthier air Less energy usage Fewer major repairs (which also leads to more savings)
Chapter 2: Problems and Resolutions There are more than 100 components in an average HVAC system, and each has varying levels of impact on your energy usage and comfort levels. So while some things are minor and may not require much attention, others will need a little more vigilance. Common Issues that Cause Problems Obstructions in the tubes If anything at all gets into the chiller tube, it can reduce the efficiency of the heat transfer. Anything from small microbes to larger formations of scale or iron deposits can be problematic. It doesn t take much to make the heat transfer so inefficient that your energy costs and consumption begin to rise. Use a water treatment program or other professional tube cleaning services to clear out the problem. Leaks in the compressor The low-pressure chiller can develop leaks, which reduces the airflow through the unit. The worst case scenario is that this leads to air collecting on the condenser, displacing the refrigerant. This will make it harder to get the correct and consistent temperature and pressure.
You need to take the time to check your compressors and test them for leaks at least once a season. Inefficient refrigerant levels Too much or too little refrigerant can easily reduce the efficiency. Double check the refrigerant levels and make sure they match the manufacturer s recommendations. Impaired condenser flow rate Damaged or clogged valves and nozzles can hinder the flow rate of the air and refrigerant. Keep an eye on the condenser flow and, if you can determine the cause of the impairment, remove it and then retest the flow rate to make sure there isn t anything else going on in there. Flakey thermostat A thermostat that is set to run when the house is unoccupied, or one that is incapable of cycling on and off at the proper intervals, can increase your bills and strain your HVAC system. Keep an eye on the thermostat. If it has auto settings, make sure it is set to more efficient levels when no one is occupying the home. Any wiring on resistor problems will likely require a professional to fix it.
Sensor problems If your sensors are calibrated wrong, or simply don t work, you will have difficulty finding the right settings that keep you comfortable. The solution is simple. Check your sensors regularly. Replace or repair them if necessary. Airflow obstructions If you have airflow problems, you may have some blockage at some point in the ventilation. You can measure the airflow and compare it to the standard levels. If they are weak or insufficient, take steps to clear any obstructions. Dirty filters One of the simplest maintenance jobs and the one that is just as easy to overlook is replacing a dirty filter. Your filters need to be changed regularly to keep everything performing at peak efficiency. A clean air filter improves air quality in both the winter and summer, when your HVAC system is in constant use. Change them regularly. Exactly how often depends on a number of factors, so at the very least you should check the level of buildup every month. Preventative vs. Corrective Maintenance It only takes one major repair for most people to realize that there really is something to this preventative maintenance that people keep talking about. This is a particularly hard lesson when the climate outside has turned harsh and your HVAC system isn t performing well (or at all). When the temperature outside has dropped below freezing, that is the absolute worst time to find out you need a new furnace. Take the time to focus on preventative maintenance throughout your home, and your system will be more reliable throughout
the years. This isn t a difficult task, and simply involves a few activities that you perform at regular intervals. Watch for certain indicators to determine if something needs a little extra attention. Pay attention to the system startup characteristics Be aware of any strange smells Listen for abnormal noises Keep an eye on the gas pressure Double check the ventilation Watch the temperature sensor to ensure the system is cycling on and off properly Basic Maintenance and Care There are several basic activities that you can perform to avoid some of the common HVAC problems. These are some simple maintenance procedures that anyone can do and can help extend the life of your equipment. 1. Change the filter every month 2. Remove leaves and debris from the outdoor condensers 3. Clean the fan blades every season
4. Cut back any growth around the outdoor equipment 5. Lubricate any moving parts 6. Clean the indoor evaporator coil 7. Tighten all electrical connections 8. Double check the thermostat settings Seasonal Care Some maintenance activities are particularly important during certain seasons or are only necessary at specific times during the year. When the weather starts to change, make sure you take care of your HVAC system and treat them appropriately. 9. Check the controls for responsiveness 10. Inspect fan blades for damage or misalignment 11. Monitor the starting cycle of all equipment 12. Check the condensation drain 13. Change the thermostat batteries 14. Make sure the right breakers and switches are on 15. Check the ductwork for obstructions or leaks 16. Clear the grills and registers Winter Care When the temperatures start to drop, you need to make sure the heater is ready to do some hard work and the air conditioner is properly bundled up for a few months of inactivity. This could include:
Cover the AC unit Replace filters Inspect the belts and replace if needed Lubricate all motors or other moving parts Blow out the condensate drain and clean the pan a restricted drain opening can cause a lot of problems for your equipment Inspect the compressor Make sure there is no refrigerant leaking Check all the electrical connections Inspect and replace any degraded belts Clean the evaporator and condenser air conditioning coils Clean and adjust the blower components Inspect the heat exchanger and burner assembly Check the gas or oil connections make sure they are secure and that there are no leaks (or potential leaks) Make sure the furnace flame is burning properly Spring Care Now that it s time to dust off the AC controls and counter the oncoming summer heat, there are a few more things you need to do. (Though you may note that some of these activities are the same as those you did in the winter.) Uncover the AC unit Replace filters Blow out the condensate drain and clean the pan Wash the condenser coil
Chapter 3: When to Let Others Handle It & When to Start Over DNDIY (Do Not Do It Yourself) While the majority of HVAC maintenance falls squarely in the DIY category and can be done by anyone with a little knowhow and mechanical skill, there are a few things that should be left to the professionals. Some people are determined to do everything on their own which, in most cases, is fine. It is a way to save money and break out some of those tools that are sitting out in your garage without anything to do. However, an HVAC system is actually very complex, and a lot of different parts have to work together every day. Sometimes you need to fight off your urge to do everything yourself and let the professionals do what they do best. This may include: Fixing fan blades If you find that the fan blades are bent, don t try to reshape them yourself. You ll most likely unbalance them and cause new problems. A replacement is likely your best option here. Getting into the walls If you suspect a problem in the ductwork behind the walls, don t just go knocking holes in the sheetrock. There are better ways to find the source of the trouble. Handling Freon Anything that involves handling the refrigerant, Freon, should be done by people who are
properly certified. Since an accident with this chemical can lead to serious harm, you can actually be fined for trying to handle it without a license. Overheating problems If the engines or compressors are overheating (usually spotted by acrid and musty smells), this will require a professional to discover and repair the problem. Electrical replacements Any issues with an electrical system should be left to someone who has experience discovering, repairing, or replacing the problem. Electricity is dangerous, and you could harm yourself with even a small miscalculation. When Do You Start From Scratch? Sometimes, despite all your efforts, it is simply more practical and efficient to replace part or all of your HVAC system. Maybe you just moved into a home where the system is in disrepair, or maybe your energy bills are still going up no matter how much preventative maintenance you do. A replacement is always a big decision, though, so this is normally a last resort. You can determine if it s necessary by certain characteristics or if it acts in a certain way. The HVAC system is at least 10 years old The compressor or furnaces runs much longer than it used to, meaning that it cycles on and off at unpredictable and inefficient times A heat-loss calculation determined that even with the current state of home insulation, airtightness, and the local climate, you re still losing an unacceptable amount of heat Replacements should only be necessary after completing all the maintenance and repairs you (or a professional) can. So before you make that final decision, consider having an energy assess-
ment done by a specialist in energy efficiency to determine if it s the HVAC that is underperforming or if there is something else underlying the problem. Focus On What You Can Do While there are some situations in which it is better to call a professional, it s important to stay on top of things and avoid the worst problems. The good news is that there really is a lot you can do to keep everything performing well you just have to take the time to do it. The proper maintenance can significantly reduce your energy costs, build the comfort levels in your home, and extend the life of your equipment. Some of these things are so simple and easy, though, that they re easy to forget. You don t have to be a DIY enthusiast to complete these activities on a regular basis, but if you focus on the things you can do, your HVAC equipment will keep you nice and comfortable in your home without sending the energy costs through the roof.
Resources: https://www.energystar.gov/index.cfm?c=heat_cool.pr_maintenance http://www.institutebe.com/building-performance-management/studies-show-hvac-system-maintenance-saves-energy.aspx http://www.bestpickreports.com/blog/post/the-language-of-hvac-how-heating-andcooling-systems-work