When your furnace won’t start, doing your own furnace repair in New Castle, Pennsylvania, can feel pretty overwhelming.

Troubleshooting your furnace might feel like an overwhelming job when your heat won’t power on. But it doesn’t have to be like that.

There are a few fast, reasonable fixes you can do on your own to prevent a furnace repair call.

If your furnace won’t turn on, won’t stay on or won’t ignite, try the troubleshooting list below before getting in touch with an HVAC professional.

If you find you need help from a heating and cooling expert and live in New Castle, Central Heating & Plumbing can assist you. We can repair most brands of heating systems and also provide emergency furnace repair.

If it’s time for a new heating system, we also offer furnace installation.

While you’re talking with us, think over a routine furnace maintenance plan that may help you avoid repairs in the future. We can tell you how frequently your furnace should be inspected by one of our NATE-certified professionals.

Go through our easy guide below to get to work on troubleshooting your furnace. Most of these steps don’t require mechanical abilities.

Furnace Repair Checklist

1. Check the Thermostat

To start, make sure your thermostat is signaling your furnace to turn on.

Digital Thermostat

Swap out the batteries if the screen is blank. If the digital screen is jumbled, the thermostat may need to be replaced.

Make sure the switch is set to “heat” as opposed to “off” or “cool.”

Ensure the program is displaying the correct day and time and is set to “run.” If you’re having problems overriding the program, set the temperature by using the up/down arrows and press the “hold” button. This will make the furnace to ignite if thermostat programming is causing a problem.

Increase the temperature setting to 5 degrees warmer than the room temperature.

If your furnace hasn’t started within few minutes, make sure it has power by toggling the fan switch from “auto” to “on.” If the fan doesn’t run, your furnace could be without power.

Smart Thermostat

If you have a smart thermostat—like one made by Nest, Ecobee, Lux, Honeywell or Bosch—troubleshooting is very model-specific. Refer to the manufacturer’s website for help. If you still can’t get your Wi-Fi thermostat to work, call us at 724-401-1843 for heating and cooling service.

2. Examine Breakers and Switches

Next, you will need to check if your breaker and furnace switch are on.

Look for your house’s main electrical panel. If you don’t know where it is, look for a gray metal box in your basement, garage or closet.

Make sure your hands and feet are dry before touching the panel or breakers.

Look for the breaker labeled “furnace” or “heat,” and make sure it’s switched “on.” If the breaker has tripped, it will be in the middle or “off” position.

Using one hand, firmly switch the breaker to the “on” position. If the breaker immediately trips and pops back to “off,” don’t touch it and contact a professional from Central Heating & Plumbing at 724-401-1843 right away.

It doesn’t matter how old your furnace is or what brand it is, it has at least one standard wall switch located on or near it.

Make sure the switch is flipped up in the “on” position. If it was turned off, expect your furnace to take up to five minutes to start. (If you don’t know where to find your furnace, take a look at your basement, garage or utility closet. It could also be in a crawl space or attic.)

3. Replace the Air Filter

When it comes to furnace breakdown, a dirty, clogged air filter is often to blame.

If your filter is too dirty:

  • Your furnace won’t keep heating your home, or it could overheat from reduced airflow.
  • Your energy bills could increase because your furnace is turning on too often.
  • Your furnace could break down sooner than it should because a dirty filter causes it to overwork.
  • Your furnace can lose power if an overly dirty filter causes the breaker to trip.

Depending on what type of furnace you use, your air filter can be found inside the blower compartment of your furnace, an attached filter case or wall-mounted return air grille.

To replace your filter:

  1. Turn off your furnace.
  2. Remove the filter and tilt it toward the light. If you can’t see light through it, replace it.
  3. Install the new filter with the arrow pointing toward the furnace to avoid damage.

Flat filters should be replaced monthly, while pleated filters should last about three months. You can also buy a washable filter that will last about 10 years. If you have children or pets, you may have to put in a new filter more frequently.

To make the process easier in the future, use a permanent marker on your furnace housing or ductwork to list the airflow direction and filter size.

4. Inspect the Condensate Pan

Commonly known as drain pans, condensate pans catch water your furnace removes from the air.

If water is seeping out of your furnace or its pan has standing water in it, follow these steps.

  • If your pan has a drain (look for a PVC pipe), check that it’s clear. If it needs to be drained, use a special pan-cleaning tablet you can purchase at home improvement or hardware stores.
  • If your pan has a pump, take a look at the float switch. If the switch is stuck “up” with standing water in the pan, contact us at 724-401-1843, because you will likely need a new pump.

5. Check for Furnace Error Codes

If malfunctions persist, peek inside your furnace’s plastic window to verify the status of the blower motor. Depending on the model, the light could also be attached on the outside of your furnace.

If you see anything except a steady, colored light or blinking green light, call us at 724-401-1843 for HVAC service. Your furnace may be giving an error code that needs professional service.

6. Clean the Flame Sensor

If your furnace tries to start but turns off without blowing heat, a dirty flame sensor could be responsible. When this occurs, your furnace will try to turn on three times before a safety feature turns it off for about an hour.

If you feel comfortable with opening up your furnace, cleaning your flame sensor is something you can do on your own. Or, one of our heating service experts can do it for you.

If you want to clean the sensor yourself, you’ll need:

  • A 1/4” hex screwdriver or wrench
  • Piece of light grit sandpaper, steel wool or emery cloth
  • A dry, clean paper towel

Next:

  • Disable the furnace’s power by using its wall switch or breaker. If your gas valve is not electric, you will need to shut off the gas as well.
  • Lift off the furnace’s front panel and trace the wire to the flame sensor.
  • Unscrew the rod and use your sandpaper, steel wool or emery cloth to gently rub the metal rod.
  • Wipe off the rod with a paper towel.
  • Remount the sensor.
  • Replace the furnace doors.
  • Turn the furnace’s power back on. It could go through a set of checks before resuming normal operation. If your furnace doesn’t start, the sensor may need to be replaced or something else may be wrong. If this happens, contact us at 724-401-1843 for heating and cooling repair assistance.

7. Relight the Pilot Light

If you have an older furnace, the pilot light could be turned off. To relight it, find the instructions on a label on your furnace, or follow these steps.

  • Look for the switch on the bottom of your furnace labeled “pilot,” “on” and “off.”
  • Turn the switch to the “off” position.
  • Wait at least five minutes to avoid possibly creating a fire.
  • Turn the knob to “pilot.”
  • Push the “reset” button as you bring the flame of a long lighter to the pilot light opening.
  • Release the “reset” button once the pilot light is lit.

If you have followed the instructions twice and the pilot light still won’t light or stay lit, contact us at 724-401-1843 for furnace service.

Check Your Fuel Source

Try using another gas appliance. If it doesn’t work, your natural gas service could be turned off, or you could be out of propane.

We Can Help with HVAC Repair

Followed our troubleshooting guide but your furnace still won’t work?

Call us today at 724-401-1843 or contact us online. We’ll come out and figure out the problem.

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