HVAC Problems: Diagnosing These Common Issues

Posted on February 17th, 2020 by carrolladmin

When any component of your HVAC system fails, it can throw everything off. Some of the more common HVAC problems (and how to diagnose them) are described below.

Clogged Air Filter

One of the most common HVAC problems is a clogged air filter. 

The air filter is designed to keep allergens and other indoor pollutants to a minimum in your home, and when it gets clogged, it can no longer perform that task. In addition, it can put extra strain on the entire heating and cooling system.

Signs of a clogged filter

If you see any of the following, it may mean your air filter is clogged:

  • Visible dust and debris caking the air filter itself
  • Your home has more dust accumulation than normal
  • Your home takes too long to cool off or warm-up
  • Allergy symptoms among those in your home are getting worse
  • The circuit breaker to the AC/furnace system keeps tripping

Fixing a clogged filter

Fortunately, a clogged air filter is pretty easy to fix. Before doing anything, however, make sure your system is turned off. That will keep it from cycling while you’re replacing the filter.

If you have a disposable air filter, simply change it out for a new one. Just make sure you have the right size and shape. Consult your owners’ manual to determine the right filter for your system and to find where the filter is installed.

If you have a reusable filter, wash it with soap and water, let it dry, and then reinstall it.

In either case, it’s best to change/clean the filter every few months.

Blower Motor Issues

A ducted HVAC system uses a blower motor to circulate warm or cool air throughout your home. The motor powers a fan which then draws air out of the furnace/AC system and distributes it through your home’s ductwork. If something goes wrong with the blower system, your HVAC system won’t have as much control over your home’s temperature.

Signs of blower motor issues

There are many ways a motor blower might go bad, and you might notice one or more of the following symptoms if it does.

  • Circuit breaker keeps tripping
  • Rattling or other noises
  • Poor (or no) airflow from vents
  • Intermittent blowing
  • Burning smells coming from the vents
  • Higher energy bills

Fixing a blower motor

The blower motor is a complex piece of equipment, and if it’s going bad, it will need some thorough diagnostics to tell exactly what’s going wrong.

It may be as simple as a buildup of debris inside (often causing strange noises), which is an easy fix. However, there may be a problem with the motor relay—the system that signals the blower on and off—or with the motor itself. In those cases, it will likely need replacement.

In general, if you think your system has a problem with the blower motor, you’ll want to contact an HVAC professional to resolve the issue.

Malfunctioning Thermostat

In many cases, an HVAC problem has little to do with the heavy equipment and more to do with the delicate thermostat that controls the entire system. If there’s an issue with your thermostat, nothing will quite work the way it’s supposed to.

Signs of a malfunctioning thermostat

If your thermostat isn’t working properly, you might notice the following issues.

  • AC and heating runs constantly without turning off
  • AC and heating won’t turn on
  • Rooms furthest away from your furnace/AC unit don’t get heated/cooled
  • The thermostat itself is unresponsive, even after changing the batteries

Fixing the thermostat

First off, if your system keeps blowing, you might just need to switch the fan from “on” to “off.” Often, this is a simple fix.

If that doesn’t do anything, then you might need to restart the thermostat by turning it off, waiting 30 seconds, and then turning it on again.

If neither of those work, it may be time to replace your thermostat. This is best done by a professional since it requires correctly wiring the system and securely mounting it to your wall.

Evaporator and Condenser Coil Problems

The evaporator and condenser coils form a part of your air conditioning system, and if they get clogged or damaged, it can keep your AC from cooling your home properly.

Signs of clogged coils

If your system’s evaporator and condenser coils are clogged, you’ll likely see these symptoms:

  • High energy consumption
  • Reduced cooling
  • The system runs longer than usual
  • Coils get frozen up

Fixing clogged evaporator and condenser coils

The coiling in these systems can be difficult to reach and very delicate, which means evaporator coil cleaning is typically best left to the professionals. They’ll have the tools needed to clear any debris away and get your system up and running once more.

Faulty Pilot Light

Gas furnaces use a pilot light to burn gas. If it wears out or stops functioning altogether, it will keep your furnace from working at all. In some cases, the issue may lie with the thermocouple, which shuts off the light if the flame isn’t burning properly.

Signs of a faulty pilot light

To tell if your system’s pilot light isn’t working properly, look for these signs:

  • The system short cycles
  • The system doesn’t turn on at all
  • Pilot light burns yellow or orange instead of blue

Fixing a faulty pilot light

If your furnace’s pilot light has gone out, you might be able to relight it on your own. To do so, do the following:

  • Shut off the gas, and wait three minutes
  • Switch the gas over to the “pilot” setting
  • Light a match and hold it to your pilot light’s opening
  • Press and hold the reset button on your pilot control until it lights up again
  • Set the gas valve to “on”

If that doesn’t work, you’ll want to contact a professional to replace it.

Getting Professional Help For HVAC Problems 

If you need HVAC repairs, promptly contact a qualified HVAC professional at Carroll Plumbing to help.

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