Furnace Repair Checklist
1. Inspect the Thermostat
First, make sure your thermostat is telling your furnace to start.
- Swap out the batteries if the screen is empty. If the digital monitor is mixed up, the thermostat may need to be replaced.
- Make sure the control is set to “heat” rather than “off” or “cool.”
- Ensure the program is showing the appropriate day and time and is programmed to “run.” If you’re having trouble overriding the setting, adjust the temperature with the up/down arrows and holding the “hold” button. This will cause the furnace to start if thermostat is causing trouble.
- Increase the temperature setting to 5 degrees hotter than the temperature of the room.
If your heater hasn’t turned on within several minutes, make certain that it has power by switching the fan switch from “auto” to “on.” If the fan doesn’t start, your heating system could be without power.
If you utilize a smart thermostat—such as one made by Nest, Ecobee, Lux, Honeywell or Bosch—troubleshooting is very model-specific. Take a look at the manufacturer’s website for help. If you aren’t able to get your Wi-Fi thermostat to operate, call us at 805-242-9638 for heating and cooling service.
2. Check Breakers and Switches
Next, confirm your breaker and furnace switch are on.
- Locate your main electrical panel. If you don’t know where it is, keep an eye out for a silver metal box in your basement, garage or closet.
- Ensure your hands and feet aren’t moist in advance of touching the panel or breakers.
- Look for the breaker titled “furnace” or “heat,” and double-check it’s turned “on.” If you discover a tripped breaker, it will be in the middle or “off” area.
- Moving one hand, quickly switch the breaker to the “on” position. If the breaker trips right away and pops back to “off,” don't try to reset it and contact a professional from Allstar Heating & Air Conditioning at 805-242-9638 immediately.
Regardless of your furnace’s age or brand, it has at minimum one regular wall switch installed on or close to it.
- Make certain the switch is facing up in the “on” position. If it was shut off, expect your furnace to take up to five minutes to start. (If you don’t know where your furnace is located, look in your basement, garage or utility closet. It can also be in a crawl space or attic.)
3. Get a New Air Filter
When we think about furnace breakdowns, a dirty, full air filter is regularly the top offender.
If your filter is too dirty:
- Your furnace won’t stay on, or it could get too hot from reduced airflow.
- Your energy costs might increase because your heat is working too often.
- Your furnace might stop working too soon since a dusty filter triggers it to work harder.
- Your heating might lose power if an overly clogged filter is the cause of a tripped breaker.
Based on what make of heating system you use, your air filter is located within the blower compartment of your heating system, an attached filter case or wall-mounted return air grille.
To replace your filter:
- Switch off your heater.
- Remove the filter and tilt it toward the light. If you can’t see light through it, get a new one.
- Put in the new filter with the arrow facing toward the heating system to keep damage from happening.
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 change your filter sooner.
To make the procedure easier down the line, write with a permanent writing tool on your heater exterior or ductwork to show the airflow direction and filter size.
4. Check the Condensate Pan
Otherwise known as drain pans, condensate pans hold water your furnace pulls from the air.
If liquid is seeping out of your heater or its pan is overflowing, try these recommendations.
- If your pan includes a drain (look for a PVC pipe), check that it isn’t full. If it should be drained, use a special pan-cleaning tablet you can purchase at home improvement or hardware stores.
- If your pan contains a pump, inspect the float switch. If the lever is stuck “up” with standing water in the pan, call us at 805-242-9638, because you will probably have to get a new pump.
5. Check for Heater Error Codes
If faults keep on happening, look within your furnace’s plastic window to check the blower motor’s status. Dependent on the model, the light could also be fixed on the outside of your heater.
If you notice anything other than a solid, colored light or flickering green light, contact us at 805-242-9638 for HVAC service. Your heating system could be giving an error code that is calling for expert assistance.
6. Brush off the Flame Sensor
If your furnace tries to work but turns off without distributing warm air, a dusty flame sensor might be responsible. When this happens, your furnace will make an attempt to ignite three times before a safety mechanism turns it off for around an hour.
If you feel comfortable with removing the panels from your furnace, brushing off your flame sensor is work you are able to do personally. Or, one of our heating service professionals is able to finish it for you.
If you are fine with cleaning the sensor personally, 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
- Shut off the heater’s power with its wall switch or breaker. If your gas valve isn’t electric, you have to turn off the gas as well.
- Remove the heater’s front panel and follow the wire to the flame sensor.
- Take off the rod and use your sandpaper, steel wool or emery cloth to lightly clean the metal rod.
- Clean the rod with a paper towel.
- Remount the sensor.
- Secure the furnace doors.
- Turn the furnace’s power back on. It could run through a series of inspections before resuming usual running. If your heating system doesn’t ignite, the sensor might require replacement or something else might be causing a problem. If this takes place, call us at 805-242-9638 for heating and cooling repair help.
7. Reignite the Pilot Light
If you own an older heater, the pilot light could be extinguished. To reignite it, look for the guide on a label on your heating system, or follow these recommendations.
- Look for the toggle beneath your furnace marked “pilot,” “on” and “off.”
- Move the switch to the “off” position.
- Don’t do anything for at least five minutes to avoid starting a fire.
- Turn the switch to “pilot.”
- Push the “reset” button as you push the flame of a long lighter to the pilot light opening.
- Release the “reset” switch once the pilot light is lit.
If you have tried the instructions twice and the pilot light still won’t light or keep lit, contact us at 805-242-9638 for furnace service.
Examine Your Gas Source
Try turning on a second gas appliance. If it doesn’t operate, your natural gas service may be shut off, or you could be out of propane.