Furnace Repair Checklist
1. Inspect the Thermostat
First, make sure your thermostat is signaling your furnace to start.
- Change the batteries if the display is empty. If the digital screen is scrambled, the thermostat may need to be swapped out.
- Ensure the switch is on “heat” rather than “off” or “cool.”
- Make sure the program is showing the right day and time and is scheduled to “run.” If you’re having a hard time overriding the program, adjust 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.
- Turn the temperature setting to 5 degrees hotter than the room temperature.
If your furnace hasn’t kicked on within several minutes, make sure it has power by switching the fan switch from “auto” to “on.” If the fan doesn’t operate, your furnace might not have power.
If you use a smart thermostat—such as one designed by Nest, Ecobee, Lux, Honeywell or Bosch—troubleshooting will depend on your model. Take a look at the manufacturer’s website for support. If you aren’t able to get your Wi-Fi thermostat to function, contact us at 512-937-2001 for heating and cooling service.
2. Examine Breakers and Switches
Next, confirm your breaker and furnace switch are on.
- Look for your main electrical panel. If you have no idea where it is, search for a silver metal box in your basement, garage or closet.
- Ensure your hands and feet aren’t wet before using the panel or breakers.
- Look for the breaker labeled “furnace” or “heat,” and make sure it’s switched “on.” If you discover a tripped breaker, it will be in the middle or “off” spot.
- With one hand, quickly flip the breaker to the “on” position. If the breaker immediately trips and pops back to “off,” don't try to reset it and contact an expert from Miller Climate Control LLC at 512-937-2001 right away.
No matter your furnace’s age or brand, it has at minimum one ordinary wall switch located on or close to it.
- Make certain the lever is moved up in the “on” placement. If it was switched off, it could take your furnace up to five minutes to start. (If you don’t know where to locate your furnace, look in your basement, garage or utility closet. It may also be in a crawl space or attic.)
3. Put in a New Air Filter
When we think about heating problems, a dirty, blocked air filter is regularly the top culprit.
If your filter is too dusty:
- Your heater won’t stay on, or it might get too warm from restricted airflow.
- Your heating bills could increase because your heater is switching on more than it should.
- Your heating system may stop working prematurely since a dirty filter causes it to work overtime.
- Your heating may be disconnected from power if an excessively dirty filter causes the breaker to trip.
Depending on what model of heater you have, your air filter is located within the blower compartment of your heating system, an attached filter case or wall-mounted return air grille.
To put in a new filter:
- Switch off your heating system.
- Take out the filter and angle it toward the light. If you can’t see light through it, get a new one.
- Install the new filter with the arrow pointing toward the heating system to prevent damage.
Flat filters ought to be replaced every month, while pleated filters should last about three months. If you have children or pets, you could have to change your filter sooner.
To make the process easier down the line, draw with a permanent marker on your heating system exterior or ductwork to show the airflow direction and filter size.
4. Check the Condensate Pan
Otherwise known as drain pans, condensate pans capture liquid your heating system draws from the air.
If water is leaking out of your furnace or its pan has too much water in it, use these recommendations.
- If your pan includes a drain (look for a PVC pipe), double-check that it’s clear. If it needs to be drained, get a special pan-cleaning tablet you can get at home improvement or hardware stores.
- If your pan has a pump, check the float switch. If the lever is stuck “up” with water in the pan, call us at 512-937-2001, because you will probably have to get a new pump.
5. Look for Heating Error Codes
If faults persist, peek within your heating system’s plastic window to check the blower motor’s status. Subject to the model, the light might also be attached on the surface of your heating system.
If you note anything other than a solid, colored light or flickering green light, contact us at 512-937-2001 for HVAC service. Your heater could be communicating an error code that is calling for pro help.
6. Clean the Flame Sensor
If your heater tries to operate but switches off without putting out warm air, a filthy flame sensor might be responsible. When this occurs, your heater will make an attempt to ignite three times before a safety feature shuts it down for approximately an hour.
If you feel confident with opening up your furnace, cleaning your flame sensor is a task you have the ability to do personally. Or, one of our heating service specialists has the ability to do it for you.
If you are fine with cleaning the sensor on your own, you should have:
- A 1/4” hex screwdriver or wrench
- Bit of light grit sandpaper, steel wool or emery cloth
- A dry, clean paper towel
- Disable the heater’s power through its wall switch or breaker. If your gas valve isn’t electric, you will need to turn off the gas in addition.
- Lift off the heater’s front panel and follow the wire to the flame sensor.
- Unscrew the rod and use your sandpaper, steel wool or emery cloth to lightly scrub the metal rod.
- Wipe off the rod with a paper towel.
- Put the sensor back in.
- Replace the furnace doors.
- Switch the furnace’s power back on. It might proceed through a sequence of tests before continuing usual operation. If your furnace doesn’t ignite, the sensor may have to be replaced or something else could be causing a problem. If this takes place, call us at 512-937-2001 for heating and cooling repair assistance.
7. Relight the Pilot Light
If you own an older heating system, the pilot light could be turned off. To light it, look for the steps on a sheet on your furnace, or use these recommendations.
- Find the switch beneath your heating system marked “pilot,” “on” and “off.”
- Push the switch to the “off” position.
- Wait at least five minutes to limit the possibility for sparking a fire.
- Turn the knob to “pilot.”
- Hold down the “reset” lever as you push the flame of a long lighter to the pilot light opening.
- Depress the “reset” lever once the pilot light is burning.
If you have tried the instructions twice and the pilot light still won’t burn or keep ignited, contact us at 512-937-2001 for furnace service.
Examine Your Energy Supply
Try using a second gas appliance. If it doesn’t work, your natural gas source may be switched off, or you might have run out of propane.