5 Simple Furnace Fixes You Can Perform

When your furnace stops keeping up on a chilly evening, it is natural to worry about a big repair bill. The good news is that many heating issues in Rancho Cordova homes come from small, simple problems that homeowners can safely check on their own. As technicians at Fox Family Heating and Air Conditioning, we see the same basic issues over and over again at the beginning of each heating season, especially during the first cold snap that usually hits Sacramento in late November.

This article explains five basic furnace checks you can handle yourself without opening gas lines, taking apart burners, or working on live wiring. Along the way, we will point out where the limits are so you know exactly when it is time to stop troubleshooting and call a professional for help.

Safety First: Know Your Limits

Before touching any part of your heating system, take a moment to think about safety. Gas furnaces combine electricity, combustion, and exhaust venting. When something is not right, the safest choice is often to bring in a licensed technician instead of trying to push through on your own.

Keep these safety guidelines in mind for every fix below:

• Turn off power to the furnace at the service switch or breaker before removing any panel or touching wiring.
• Never attempt to adjust gas piping, gas valves, or burner assemblies on your own.
• If you smell gas, hear hissing, or see scorch marks, leave the area and contact your gas utility or emergency services before anyone re-enters the home.
• Do not bypass safety devices such as door switches or pressure switches.
• Stop immediately if any step feels confusing or uncomfortable and schedule a visit instead.

Here in the Sacramento Valley, our winters are generally mild, with the coldest temperatures in December and January and overnight lows that hover around the upper 30s. That mild climate makes gas furnaces very reliable overall, but it also means they can sit for long stretches without running. When that first cold storm rolls through in late November, it is common for our technicians to find clogged filters, closed vents, or minor thermostat issues that are easy for homeowners to prevent.

If any of the steps below reveal something you are not sure how to handle safely, Fox Family can take it from there. You can always call us or schedule a visit online.

1. Check or Replace the Furnace Air Filter

The number one simple furnace fix we recommend is checking the air filter. A dirty filter restricts airflow through the furnace. That can cause poor heating performance, noisy operation, or even safety shutdowns if the system overheats.

Most homes in Rancho Cordova and Sacramento use 1-inch or 2-inch disposable filters installed either in a return grille or inside the furnace cabinet where the return duct connects. If you are not sure where your filter is, start at the largest return grille in a hallway or ceiling, then check for a filter slot where the duct connects to the furnace.

Once you find the filter location, follow these steps:

1. Turn off the furnace at the thermostat so it is not running while you work.
2. Slide the filter out and check the arrow on the frame so you know which way the airflow should move when you reinstall.
3. Hold the filter up to a light. If you can barely see light through it, it is time to replace it.
4. Install a new filter of the same size with the airflow arrow pointing toward the furnace.

For most homes, we recommend checking the filter every month during peak heating or cooling seasons and replacing it at least every 60 to 90 days. Homes with pets, construction dust, or allergies may need more frequent changes.

If you notice that your filter becomes dirty very quickly, or if you are not sure which type of filter is best for your system, our technicians can review options during a maintenance visit and help you choose a filter that balances airflow and air quality for your home.

2. Confirm Your Thermostat Settings

Thermostat issues are another common reason homeowners call us for a “no heat” problem that ends up being a simple fix. Before assuming the furnace has failed, take a few minutes to double-check that the thermostat is actually asking for heat.

Walk through these steps:

1. Make sure the thermostat is set to “Heat” rather than “Cool” or “Off.”
2. Confirm that the temperature setting is higher than the current room temperature by at least three degrees.
3. If your thermostat has a “Fan” setting, leave it on “Auto” for normal operation while troubleshooting. An “On” fan setting will run the blower without actually heating the air, which can make it feel like the furnace is not working.
4. For battery-powered thermostats, replace the batteries if you see a low-battery symbol or if they have not been changed in the last year.
5. Check for programmed schedules that may be turning the heat down at certain times, especially overnight or while you are at work.

After making adjustments, give the system a few minutes to respond. You should hear the furnace start a heat cycle shortly after the thermostat calls for heat. If the thermostat screen is blank, flickers, or will not respond to button presses, that is a sign that the thermostat itself may be failing and should be inspected by a professional.

3. Verify Power: Furnace Switch and Circuit Breaker

Every gas furnace depends on electrical power for the control board, blower motor, and safety devices. If the furnace is completely unresponsive with no sound, no lights, and no blower operation, loss of power is often the cause.

Start with the furnace disconnect switch. This typically looks like a regular light switch mounted on or near the furnace cabinet. It is easy for someone to bump this switch while storing boxes in the garage or attic.

1. Locate the switch near the furnace and confirm it is in the “On” position.
2. If it was off, turn it on and wait several minutes to see if the furnace starts a heating cycle.

Next, check your home’s electrical panel:

1. Find the breaker labeled “Furnace,” “FAU,” or “Heat.”
2. If the breaker handle is in the middle or “Off” position, reset it by moving it fully to “Off,” then back to “On.”
3. Stand to the side while resetting the breaker and keep your eyes and face away from the panel for safety.

If the breaker trips again immediately or repeatedly, do not continue resetting it. That is a sign of an electrical problem that needs a qualified technician. At that point, turn the breaker to “Off” and contact Fox Family for service instead of continuing DIY work.

4. Make Sure Supply Vents and Returns Are Clear

Restricted airflow can make a furnace feel weak even when it is running. Closed vents and blocked returns are especially common in rooms where furniture has been rearranged or where people are trying to “save energy” by closing off vents.

In a typical Sacramento home, your furnace and ductwork were designed to move a certain amount of air through the system. When that airflow is blocked, you may notice rooms that never quite warm up, hot and cold spots, or a furnace that cycles on and off more frequently than normal.

Walk through your home and check:

• Every supply vent is open, with the louvers in a mostly open position.
• Furniture, rugs, or curtains are not covering any supply vents or large return grilles.
• Return grilles are not blocked by boxes, wall hangings, or pet beds.

If you have ever closed vents in unused rooms on purpose, reopen them and give the system a day or two to run. Many homeowners are surprised at how much more even the temperature feels once airflow is restored through the entire duct system.

If you still notice hot and cold spots after opening vents and checking the filter, Fox Family can evaluate your duct design, static pressure, and overall airflow during a professional inspection.

5. Inspect the Condensate Drain Line (High Efficiency Furnaces)

If you own a high-efficiency condensing furnace, usually rated 90 percent AFUE or higher, the furnace produces water as it operates. That condensate water drains through a plastic or PVC line that often runs to a floor drain, condensate pump, or exterior drain point. When that drain line becomes clogged, the furnace may shut itself off to prevent water damage.

You can safely inspect the visible parts of the condensate drain without opening the sealed combustion cabinet:

1. Turn off the power to the furnace using the switch or breaker.
2. Look for a small plastic drain line leaving the lower part of the furnace cabinet or nearby condensate trap.
3. Make sure the line is not kinked, crimped, or pulled loose.
4. Check the end of the drain where it enters a floor drain, standpipe, or pump. Clear away lint, debris, or algae growth that you can reach without taking anything apart.
5. If there is a condensate pump, make sure it is plugged in and the discharge tubing is secure.

Some homeowners feel comfortable removing a removable cap on a condensate trap and gently flushing it with warm water. If you try this, keep towels nearby, replace any caps securely, and restore power only after everything is reassembled. If you see standing water inside the furnace cabinet, water leaking around electrical components, or any sign of corrosion, it is time to stop and schedule service instead of continuing DIY work.

When to Call a Professional

The five fixes above cover many of the simple furnace issues our technicians see every fall and winter in Rancho Cordova and Sacramento. They are also safe for most homeowners to attempt as long as basic precautions are followed. Once you move beyond these steps, however, you quickly enter areas that involve combustion safety, carbon monoxide risk, and more advanced electrical troubleshooting.

Call a professional if:

• The furnace still will not start after you have checked the filter, thermostat, power, vents, and condensate drain.
• You hear loud banging, screeching, or grinding noises from the furnace or blower.
• You smell gas, see flames where they should not be, or notice soot or scorch marks.
• The furnace runs for a short time, then shuts off repeatedly, and you cannot see an obvious airflow problem.
• The breaker continues to trip when the furnace tries to start.

Our technicians have the tools to measure gas pressure, check flame sensors, analyze combustion, and verify that your furnace is operating safely. Those are not tasks that should be attempted without training and proper test equipment.

Fox Family Is Here When You Need Help

Taking a few minutes to perform these simple checks can often restore heat quickly without a major repair, especially during the first cold spell of the season. Even when the problem turns out to be more serious, you will have a better understanding of what your system is doing and what you have already ruled out.

If you would like a professional to give your furnace a thorough inspection before winter settles in, Fox Family Heating and Air Conditioning offers maintenance and repair services throughout Rancho Cordova, Sacramento, and the surrounding communities. Our goal is to keep your home comfortable, safe, and efficient all winter long.