If you've endured the last vestiges of a summer heat wave and are finally beginning to unpack the fall decor and heavier sweaters, you're likely doing some late-summer cleaning and home maintenance. In the course of making sure your furnace is ready to power through another winter, you could be dismayed to discover that it won't turn on -- or that it runs for only a few seconds or minutes and then shuts off without providing much heat. Are you facing a hefty repair bill, or is this something you can diagnose and fix yourself? Read on to learn how you can troubleshoot to determine the exact problem (or problems) preventing your furnace from igniting or staying on after a long summer break.
Where should you begin when diagnosing a furnace that won't turn on?
Your best bet whenever dealing with a large appliance that isn't functioning properly is to begin with the simple fixes first. In many cases, a few minutes of investigation or repair work can prevent you from incurring the expense of a service call for what ends up being a very minor repair.
If your furnace won't turn on at all, you'll want to check the circuit breakers that service its power source. If your home was hit by a lightning strike or other power surge over the summer, it's possible the circuit breaker tripped without tipping you off, especially if your furnace is in the basement or another area you don't frequently visit. You may also want to examine your furnace itself for any exterior circuit breakers or power savers that may have tripped over the summer.
Once you've ruled out circuit breaker issues as the cause of your furnace's inaction, you'll then want to check your thermostat. If your thermostat isn't properly communicating with the rest of your furnace, it won't send the signal needed for your furnace to begin generating or blowing hot air -- even if the surrounding air itself is very cold. Battery-powered thermostats may go dead after a long period of inactivity, while hardwired thermostats could reset to factory settings following a power outage or other electric event. If your thermostat is on and set to "heating" mode, you'll need to move on to the next potential culprit.
You'll then want to carefully look over your furnace, including any drain or condensate pans, the pilot light (if you have a gas furnace), and the air filter. In many cases, the problem will become apparent once you begin looking beyond the surface of your furnace. A frozen condensate pan or one that's clogged with debris or gunk could prevent your furnace from turning on, as could a blocked air filter.
If you manage to get your furnace to start running, but it shuts off after a few minutes, you could be dealing with a faulty ignition sensor or fuel supply. In this case, either the sensor that instructs the pilot light to stay lit or the hose that supplies gas to the furnace itself could be covered with deposits or crud that is interfering with normal function.
When should you contact a professional repair service?
In some cases, you may be able to fix the problem yourself. However, if you have a natural gas furnace and are dealing with ignition supply issues, you may want to contact a professional for safety purposes. A single misstep in repairing a gas supply line could leave your home vulnerable to leaks of toxic, flammable propane or natural gas that can pose health and safety risks to you and your family. You may also want professional help if you're unable to conclusively troubleshoot the source of your furnace problems or don't trust yourself to make the necessary repairs without incurring injury. Contact a company like Custom Comfort for more info.