If something is failing or going amiss with your HVAC unit, chances are, your HVAC unit is letting you know something is not quite right. However, most of the cues come in the form of sounds that many of us may overlook. If you hear your HVAC unit grinding, squealing, screeching or squeaking, it is letting you know it needs help. I was unaware of these cues and overlooked them. It ended up costing me a lot of money in repairs. I want to make sure that does not happen to other people, so I made this website. I hope you learn how to interpret the noises your HVAC unit is making so you can get it the repairs it needs before you incur a costly repair, or worse, permanently ruin your unit for good.
Your home's HVAC system utilizes several electrical connections. Mains power, also known as supply voltage, comes from your home's service panel and supplies the electricity needed to run components such as the control board, AC compressor, furnace igniter, and so on. This supply typically comes in on a dedicated 220/240-volt line for central heating and air conditioning systems.
However, your HVAC control board also supplies power to several other components in your system. These lines are known as low-voltage connections, and they provide power to your thermostats and send command signals to components such as the compressor. Although low voltage lines don't pose the same danger as higher voltage ones, diagnosing problems with them is rarely a DIY task.
Where Does Your HVAC System Use Low-Voltage Wiring?
If you were to remove your thermostat from the wall, you'd discover several small wires connected to the back. The number of wires and their purpose will vary between systems, with older homes typically having fewer wires and newer homes with smart thermostats and multi-stage HVAC requiring more. At a minimum, you will have wires for controlling your fan and furnace.
Many homes will also include additional wiring to control the air conditioner or supply 24-volt (low voltage) power for programmable and smart thermostats. A modern, very high-efficiency furnace or air conditioner may have even more control wires to trigger second-stage heating and cooling. This sometimes large bundle of low-voltage wiring needs to run from your control board to each thermostat.
There's yet another complication with systems involving an air conditioner: the condenser control wiring. The thermostat calls the control board for cooling, but the control board must relay that signal to the condenser to engage the compressor and condenser blower. This final low-voltage line will typically run from your air handler to your outdoor condenser unit.
Why Shouldn't You Try to Resolve Low-Voltage Issues Yourself?
It should be clear by now that while low-voltage may not be dangerous, the low-voltage wiring for your HVAC system is incredibly complex. Problems can crop up in numerous places, with faults appearing due to pests chewing on wires, blown low-voltage fuses, bad thermostats, and more. Tracking down these problems can be challenging and time-consuming, even for an expert.
If you don't have experience working with HVAC electrical systems, you will likely face substantial difficulties narrowing the problem down. Even worse, you may not be able to confirm that the problem is with the low-voltage wiring, forcing you to waste hours or days looking for a wiring fault that doesn't exist.
Despite the lower voltage, the control wiring for your HVAC system is still an electrical system with many complexities and potential trouble spots. If you suspect a problem with the low-voltage wiring in your home, it's best to contact a professional to diagnose and repair the issue instead of attempting to resolve it yourself.
Reach out to an HVAC electrical repair company for more information.
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