Any furnace can be challenging. That's particularly true when one isn't working. On the other hand, furnace repair pros have good news for you. Nearly 1 out of 4 service calls could be prevented with simple fixes that cost little to nothing. In the following paragraphs, you'll learn common furnace issues and troubleshooting techniques to use.
Solution Number 1: Check Out The Thermostat To Be Sure It's Even On
Before you make the assumption that you actually have a furnace issue going on, start with some basic troubleshooting. The thermostat is a good place to start, because you want to be sure it's actually telling your furnace that it needs to come on. Thermostats can get complicated, especially the programmable ones. When thermostats have more options, they have more that might go wrong.
Be sure the switch is set to Heat. It might accidentally or inadvertently be set on Cool.
Also, check out the specific temperature setting.
Compare your temperature setting to the actual room temperature. If you put the temperature setting to 5 degrees higher than your room temperature, your furnace should kick in.
Be sure any program running is correctly displaying the day, time, and a.m. or p.m.
Trace the wires from the thermostat back to your furnace, checking for breaks. This is especially important if you've done any recent remodeling. If you find a break in any of these thin wires, splice that line back together and then wrap it up with electrical tape.
Replace the unit's battery. If there's a dead battery and you have a power outage, you'll wind up losing your settings, meaning the thermostat reverts to its default programming.
Open up your thermostat. Use a can of compressed air to blow out debris and dust. Also be sure that it's level and attached to the wall firmly with no loose wires.
If you aren't able to make the various program settings work, you might be able to bypass them completely. Just punch in your desired temperature using the up/down control and then press on the hold button. That should switch the furnace on if the issue is thermostat programming.
Solution Number 2: Check The Shutoff Switches And Breakers
It might sound inconceivable, but a lot of furnace technicians discover that the only actual ‘fix' a furnace needs is being turned on. Look around or on your furnace for a standard wall switch. Every furnace, regardless of what kind or age it is has one somewhere. Check your fuse or circuit breaker for your furnace too. Be sure that the front panel covering your blower motor is fastened securely. It has a push-in switch underneath it that has to be pushed down completely in order for the furnace to operate.
Solution Number 3: Change The Filters
The number one source of furnace issues is none other than dirty filters. Dirt and dust both restrict airflow, and when a filter gets too clogged, the heat exchanger is likely to overheat and then shut off too fast, meaning your house doesn't warm up. If your blower is running but you have heat coming out of it, then you should replace the filter. A dirty filter can also cause soot buildup on your heat exchanger, which reduces the efficiency of your furnace, and that can shorten its life.
Your owner's manual should show you where your filter is as well as how you can remove it. Inexpensive flat filters should be changed monthly. Be sure that the arrows are pointing towards your furnace. Pleated filters need to be at least inspected monthly. Hold them up to a light source; replace them if you aren't able to light coming clearly through them. Most manufacturers claim that pleated filters work for three months, but if you have children, pets, or excessive dust, you should change them more frequently than that.
Solution Number 4: Be Sure That The Gas Is Actually On
Just like with switches, someone might have turned off the gas valve and then neglected to reactivate it. Trace your gas line from the furnace back to the meter, and look for a handle which is perpendicular in relation to the gas pipe; if it is, turn it until it's parallel instead. The age of your furnace might also impact the repair you need. Older boilers or furnaces might have pilot lights. Take the front panel and burner cover both off before checking to make sure the pilot light is lit.
Solution Number 5: Be Sure Your Chimney Exhaust Flue Is Clear
Birds are often drawn to the warmth available in a chimney exhaust flue and then fall into it. Turn your furnace off and then tune the thermostat all the way down before dismantling your duct at the point where it exits the furnace. Check it out for debris before you reassemble those sections in the very same order and direction in which you took them out.
Solution Number 6: Flush Out Your Drain Lines
High-efficiency furnaces might drain off multiple gallons of water in one day of heating. If your drain lines get restricted by mold growth or sediment, then the furnace can shut down completely. If your drain hose does appear dirty, then remove it. Fill with a 3:1 mixture of water to bleach, wait a few minutes, and then flush it.
Solution Number 7: Watch Out For Leaky Or Blocked Ducts That Might Restrict Airflow
If your furnace does come on, but you have a few cold rooms, be sure that all of your room registers are fully open. Look at any accessible ductwork to find gaps between branching points or sections. Seal any gaps you can with special metal duct tape. Avoid using conventional cloth duct tape. It deteriorates fast, and it might also cause leaky ducts if it was previously used to seal sections.
Also look for handles that are protruding from your ductwork. These are air conditioner bypasses or dampers, and they need to be open.
Solution Number 8: Clean Off Heat Pumps And Vents
If your furnace vents out of the side of your home, be sure that nothing is blocking either the intake or exhaust vents. If either pipe is covered with window screen or screen mesh, consider replacing that with half-inch mesh hardware cloth. If you get ice clogging any of your pipes, then you'll likely have a bigger issue elsewhere in the system. Clear that off and then call a technician to discover why this is happening.
If a heat pump is what you have, make sure that you clear away leaves and grass from the outdoor compressor unit fins. Before the heating season rolls up on your calendar, hose things down gently starting from the top so that you can rinse out debris and dirt out of the housing.
Find approved local expert contractors in my area.