Furnace Repair Checklist
1. Inspect the Thermostat
First, make certain that your thermostat is instructing your furnace to ignite.
- Change the batteries if the screen is not displaying anything. If the digital display is mixed up, the thermostat might need to be changed.
- Make certain that the button is switched to “heat” as opposed to “off” or “cool.”
- Ensure the program is showing the appropriate day and time and is set to “run.” If you’re having problems getting out of the program, set the temperature by utilizing the up/down arrows and holding the “hold” button. This will cause the furnace to start if thermostat is causing a problem.
- Set the temperature setting to 5 degrees above the temperature of the room.
If your furnace hasn’t turned on within a few minutes, make certain that it has power by moving the fan switch from “auto” to “on.” If the fan doesn’t begin to run, your furnace may not have power.
If you have a smart thermostat—for example one designed by Nest, Ecobee, Lux, Honeywell or Bosch—troubleshooting will be determined by the model you have. Check the manufacturer’s website for support. If you aren’t able to get your Wi-Fi thermostat to work, reach us at 713-469-3357 for heating and cooling service.
2. Check Breakers and Switches
Next, check if your breaker and furnace switch are on.
- Locate your main electrical panel. If you have no idea where it is, keep an eye out for a metallic metal box in your basement, garage or closet.
- Make sure your hands and feet aren’t moist prior to opening the panel or breakers.
- Find the breaker marked “furnace” or “heat,” and ensure it’s switched “on.” If you find that the breaker tripped, it will be in the middle or “off” area.
- Using one hand, steadily switch the breaker to the “on” position. If the breaker instantly trips and pops back to “off,” don't try to reset it and get in touch with an expert from Marcos AC & Heating at 713-469-3357 right away.
It doesn’t matter how old your furnace is or what brand it is, it has at minimum one ordinary wall switch positioned on or by it.
- Make certain the switch is facing up in the “on” spot. If it was switched off, it could take your furnace up to five minutes to start. (If you’re unaware of where to locate your furnace, look in your basement, garage or utility closet. It may also be in a crawl space or attic.)
3. Buy a New Air Filter
When it comes to furnace issues, a grungy, full air filter is frequently the top culprit.
If your filter is too dusty:
- Your furnace won’t stay on, or it could get too warm from reduced airflow.
- Your energy costs may go up because your heater is turning on too often.
- Your heating system could stop working too soon since a dusty filter forces it to overwork.
- Your heating might be disconnected from power if an excessively clogged filter results in a tripped breaker.
While it depends on what type of furnace you have, your air filter is located within the blower compartment of your furnace, an attached filter case or wall-mounted return air grille.
To swap out your filter:
- Turn off your heating system.
- Pull out the filter and angle it toward the light. If you can’t see light through it, replace it.
- Install the new filter with the arrow facing toward the furnace to prevent damage.
Flat filters need to be replaced once a month, while pleated filters should last about three months. If you have children or pets, you could have to put in a new filter sooner.
To make the procedure easier down the road, use a permanent marker on your heater exterior or ductwork to show the airflow direction and filter size.
4. Look at the Condensate Pan
Commonly known as drain pans, condensate pans capture moisture your heater pulls from the air.
If liquid is dripping from your heater or its pan has standing water in it, use these steps.
- If your pan includes a drain (look for a PVC pipe), check that it isn’t clogged. If it should be drained, get a special pan-cleaning tablet you can buy at home improvement or hardware shops.
- If your pan uses a pump, inspect the float switch. If the switch is stuck “up” with water in the pan, contact us at 713-469-3357, because you will possibly have to get a new pump.
5. Look for Furnace Error Codes
If faults continue, peek at your heater’s plastic window to check the blower motor’s status. Dependent on the brand, the light could also be attached on the outside of your heating system.
If you notice anything else besides an uninterrupted, colored light or blinking green light, call us at 713-469-3357 for HVAC service. Your heater may be emitting an error code that needs specialized service.
6. Clean the Flame Sensor
If your heating system attempts to work but shuts off without blowing warm air, a filthy flame sensor could be to blame. When this occurs, your heater will attempt to turn on three times before a safety feature powers it down for about an hour.
If you feel confident with opening up your furnace, brushing off your flame sensor is work you are able to do on your own. Or, one of our heating service experts can do it for you.
If you are fine with cleaning the sensor personally, you require:
- A 1/4” hex screwdriver or wrench
- Piece of light grit sandpaper, steel wool or emery cloth
- A fresh paper towel
- Turn off the heater’s power with its wall switch or breaker. If your furnace’s gas valve isn’t electric, you must shut off the gas as well.
- Lift off the heater’s front panel and follow the wire to the flame sensor.
- Remove the rod and use your sandpaper, steel wool or emery cloth to carefully clean the metal rod.
- Wipe off the rod with a paper towel.
- Remount the sensor.
- Put the furnace doors back on.
- Turn the furnace’s power back on. It may go through a series of tests before proceeding with normal running. If your heating system doesn’t ignite, the sensor could require replacement or something else might be wrong. If this occurs, call us at 713-469-3357 for heating and cooling repair help.
7. Relight the Pilot Light
If you own an outdated heating system, the pilot light could be extinguished. To relight it, find the steps on a label on your furnace, or use these guidelines.
- Find the lever on the bottom of your furnace marked “pilot,” “on” and “off.”
- Move the switch to the “off” position.
- Take a break for at least five minutes to limit the possibility for creating a fire.
- Turn the dial to “pilot.”
- Push the “reset” button as you move the flame of a long lighter to the pilot light opening.
- Release the “reset” button once the pilot light is ignited.
If you have gone through the list twice and the pilot light still won’t ignite or stay ignited, get in touch with us at 713-469-3357 for furnace service.
Double-Check Your Fuel Source
Try switching on a second gas appliance. If it doesn’t operate, your natural gas delivery might be switched off, or you could be out of propane.