You turned up the furnace and anxiously waited for warm air to waft all over and make you comfy and snug. But wait, something is amiss; the vents are blowing cold air. What gives? Before you shuffle to the phone, cocooned in a comforter and winter hat to call for repairs, there are troubleshooting steps you can take on your own. Put on your DIY hat and try these tips to revive that surly furnace.
Are the Registers Open?
Okay, this one seems like a no-brainer on the surface but you’d be surprised at how often a vent register gets inadvertently closed. (Or perhaps on purpose.) If there are young kids whizzing around the house, it is entirely possible they played the “close the vent” game and if too many registers are closed, heat will build up in the furnace and cause it to automatically shut down.
Closed heat registers can also cause a furnace to work harder and longer than it is meant to, potentially shortening its lifespan. Pressure builds up in ducts which can lead to leaks or worsen those already there. Always keep at least 80 percent of your registers open to maintain efficient air flow.
Is the Thermostat Properly Set?
Another easy one to miss but it happens a lot. Be sure the thermostat is on the Heat setting and not Cool, and fan setting should be on Auto. The temperature of course must be set high enough to signal the furnace to do its thing. If everything is properly set and you still don’t have heat, be sure the thermostat is receiving power. Check the batteries and related fuses and make sure everything is clean of dust and other mess that can prevent required signals to be sent to the furnace.
Check the Door Cover and Filter
Some furnace service door covers connect to a switch that powers the furnace motor. Check to be sure this door is properly closed. Filters are another biggie and arguably the most common causes of furnace angst. Air can’t get through a dirty filter, which causes the furnace to overheat and shut down. Replace filters regularly (at least every two months) and check them to ensure they are clean. This is an easy fix but if not monitored can lead to extensive and very expensive repairs.
And don’t forget the pilot light! Standing pilot lights can go out and there’s no furnace without a pilot light. Follow your unit’s instructions to relight.
For more information on furnace diagnosis, contact the experts at Cascade Mechanical at (800) 682-5923 or cascademechanical.com.