For many facility operators, HVAC systems remain shrouded in mystery and it’s often only when something goes wrong that they have to go through a crash course. Let’s outline the major commercial HVAC parts in your heating and ventilation system. We’ll also explain how they work individually and with the rest of your HVAC system. In addition, we’ll touch on a few ways these HVAC components can fail, though this is far from an all-inclusive list.
Your thermostat is probably the most visually obvious part of the HVAC system, at least from inside the house. If the thermostat is broken, your HVAC system won’t come on or it will run excessively trying to meet a temperature that isn’t comfortable. If the temperature sensor in the thermostat is faulty, you’ll see the same problem.
Ductwork and Vents
Ductwork is the network of hoses or box-like structure that carry heated or cooled air from the HVAC system to the rest of your home. Vents are the entry points for that air into your home. A single room that’s too hot or too cold may have a vent that is closed off intentionally to save energy or blocked accidentally by dust bunnies or crimped ductwork. Ducts themselves may collapse, get kinked due to items being shifted in the attic, or have holes in them because pests chewed their way in.
Your HVAC system may be built around a single heat pump or two separate components, a furnace and air conditioner. A single heat pump is cheaper than a separate furnace and air conditioner, but it is less efficient than a specialized heating or cooling piece of HVAC equipment.
Furnaces either use natural gas, oil, coal or propane, though a number use electricity. Solar energy heaters are rare, though they are periodically used for water heating. Heat exchangers bring in the cool air in the home and warm it up using the heat generated by the furnace, though air conditioners use heat exchangers to do the opposite.
An evaporator coil is used to cool air. These are found in air conditioners and heat exchangers. The condensing unit connects to the evaporator coil. It pumps refrigerant to the evaporator coil to be turned into a gas once more, cooling down the air in contact with the evaporator coil. An expansion valve is where the hot fluid is cooled before moving to the cooler heat exchanger. The compressor is where that cooled liquid (in the case of an air conditioner) is compressed to make it hot again.
This heat exchange system is the most expensive part of the HVAC system, and there are many ways it can fail. Not only that, but only a handful of HVAC supply companies carry replacement heat exchange systems.
Failing to clean the coils allows grime to build up, insulating the coils that otherwise radiate heat, likewise interfering with the HVAC system’s function. Any component from the coils to the valves can leak. Don’t try to seal leaks with over the counter solutions; contact an HVAC professional to fix it and use parts from a reputable HVAC supply company like FS Industries.
Fans blow the air from the HVAC system into the duct work and push air from inside your home to the evaporator coil. If the HVAC system starts up and then dies, there is a fair chance the fans aren’t starting up so the unit shuts down before it overheats or wastes too much energy. Very noisy fans may be close to mechanical failure or simply have something stuck in them.
Understanding your HVAC system is not only essential for proper maintenance but will allow you to troubleshoot issues earlier. It will also allow you to understand the proper course of action to take as well as get an estimate on reparation costs.