Troubleshooting HVAC Problems

Richard Ashworth
Aug 24, 2017 · 4 min read

For someone who wants to try troubleshooting HVAC problems there are basic skill sets one needs to know and understand. That is aside from having the proper tools to find the problem. Sometimes it will require patience as troubleshooting entails looking for a problem that could be either mechanical in nature or electrical. The mechanical part will require knowledge of refrigeration and how refrigeration works. Additionally refrigeration components. The electrical part will require knowledge of control circuits, how to read an electrical diagram, and basic electrical safety.

A Heat Pump Condensing Unit

Troubleshooting HVAC Mechanical Problems

There is a lot going on when troubleshooting an air conditioner or heat pump. The compressor runs and compresses vapor refrigerant and then sends it on to the condenser. The condenser condenses the vapor into a liquid and then sends it on towards the evaporator. Before it goes into the evaporator is passes through a metering device. The metering device causes the liquid refrigerant to drop in pressure and thereby temperature. Knowing the pressure temperature relationship is important to understand when problem troubleshooting and air conditioner or heat pump. Knowing the components and how they work is also important to troubleshooting any problems that may arise. Understanding the HVAC compressor and its basic operation range for pressure and amperage draw will help you troubleshoot problems also. Understanding the different metering devices used in air conditioners and heat pumps will also help you.

Additionally, understanding the coils and proper operation of the equipment can help you be better at troubleshooting HVAC problems. It is important to maintain proper air flow across the coils and any blockages in the coils will inhibit the heat exchange process from the air to the coils. This is all related to the fans moving air across the coils and making sure the fans function properly to move a specific amount of air across those coils.

Troubleshooting HVAC Electrical Problems

The first step in this process is to understand electrical safety so you don’t get hurt or worse. The next important thing to understand is electrical circuits, voltage, amperage, and basic electrical laws e.g. Ohm’s Law. See Ohm’s Law and HVAC for a reference. You will also want to understand thermostats and how they function and even how to program a thermostat. Troubleshooting thermostat problems can be easy if you understand thermostat wiring and control circuits. Making sure the program is correct is important also especially when the HVAC equipment is modulating or has more than a single stage. More modern HVAC equipment is getting more and more complex. The complexity of the system makes it more difficult to troubleshoot without understand the basics. The complexity of the HVAC systems also, usually, makes the equipment more efficient provided everything is set up correctly. Energy efficiency is important given many factors including operating costs.

Safety in Troubleshooting

Anyone working or mechanical or electric equipment must always take into account safety. Safety is a serious matter when working around moving parts and live electrical circuits. Whether the circuits are high voltage or low voltage one must take care not to get shocked. And for those who don’t know, its not the voltage the gets you its the amperage. And it can take at little as a milli-amp to kill you if the amperage passes through your heart. Humans are very conductive to electricity and can be seriously harmed if safety procedures are not used when troubleshooting HVAC. I’ve seen people shocked even when they turn off the power to their air conditioner, heat pump or gas furnace. These systems have capacitors in them and when troubleshooting air conditioner capacitors you to know they have a charge inside them (just like a battery) even when the power is turned off. You must discharge the capacitor before touching it or it will shock you. The point is, always observe electrical safety when working around electricity. Observe mechanical safety when working around moving parts!

Troubleshooting HVAC Problems Conclusion

This is a simple essay to help one understand and discover the possible complexities of troubleshooting HVAC problems. If you want to be an HVAC Technician is important to understand these factors and learn how these systems work by starting with the basics. You can learn more about HVAC by visiting High Performance HVAC and explore the various subjects on troubleshooting HVAC problems and more.

Richard Ashworth works in the HVAC industry as a project manager commissioning data centers, hospitals, and large government and commercial facilities. When he is not working hard on a project he is playing hard at his favorite sport or traveling. He can be reached through his website at High Performance HVAC Heating & Cooling.

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