Exploring HVAC Maintenance and RepairsExploring HVAC Maintenance and Repairs

About Me

Exploring HVAC Maintenance and Repairs

Hi there, my name is Michelle. I created this site to talk to you about maintaining your HVAC system on your own and with help from contractors. Your HVAC system controls the temperature and air quality in your home. When this system starts to malfunction, you may notice a decrease in your comfort levels. You can perform preventative maintenance to keep this system running year round. From these posts you'll hopefully be able to learn about DIY and professional maintenance tasks that need to be performed regularly. My site will also cover common faults and repairs for HVAC components. Thank you.

Signs, Symptoms, And Remedies For Low-Voltage AC Shorts

You're probably aware that your home's air conditioning system draws a substantial amount of power from your house's electricity supply. For example, a typical central air conditioning system requires a dedicated 220-volt or 240-volt circuit. This high-voltage supply is necessary to power the system's compressor and blower, which are two of its most critical components.

However, your air conditioner also relies on low voltage. The low-voltage side of the system acts as a command and control line while also supplying power to your home's thermostats. The primary role of the low-voltage wiring is to signal the compressor and blower to turn on whenever a thermostat in your home calls for cooling.

How Does Your Low-Voltage AC Wiring Work?

Typical single-stage residential HVAC systems include wires to signal the furnace, air conditioner, and blower, as well as "R" and "C" wires to provide a continuous low-voltage supply for thermostats. Not all homes have C-wires, but most new constructions will. If you use a smart or programmable thermostat, you probably have a C-wire.

Under normal conditions, your thermostats signal your air conditioner over the "Y" wire whenever they need cooling. Likewise, the "G" wire controls the blower motor that distributes air throughout your home. Your thermostats will send signals over this wire based on your thermostat's fan setting, such as "auto" or "circulate."

What Can Go Wrong With Your Low-Voltage Wiring?

Shorts are the most common issue with low-voltage wiring. A short will overload the wiring, tripping the low-voltage fuse. When this happens, you'll typically get a blank screen on your thermostats, and your air conditioner will refuse to turn on. Shorts can occur almost anywhere, and they may even become a problem inside the house if you have a problem with rodents or other pests.

A low-voltage short typically isn't dangerous, but it will stop your air conditioner from running. Depending on the location and cause of the short, it may trip the fuse immediately or only under certain conditions. For example, your thermostats may work fine until you switch to cooling mode, at which point, the circuit finds a connection to the ground and blows the low-voltage fuse.

How Can You Fix a Low-Voltage Short?

Unless you can see an obvious problem (such as chewed wiring), you will almost always want an HVAC technician to diagnose a low-voltage short in your air conditioning system. These shorts can occur at any point, from the outdoor condenser unit to the air handler to your thermostats. Tracking down the source of a shorted circuit often requires careful diagnosis and tracking.

As with any electrical air conditioning problem, you should avoid using your system if you know a short exists. Even if the problem seems intermittent, it's best to keep the system off until a technician arrives. Keeping your air conditioner shut down will protect your home and help you avoid causing more damage to the control board or other expensive components. 

Contact an air conditioning repair service near you if you notice any issues.