
Furnaces present a dependable and efficient method to hold you heat throughout winter months. Sadly, like every other residence equipment, these heating systems could encounter occasional points that require troubleshooting and restore.
The issues can come up attributable to an absence of HVAC maintenance or defective elements. Different elements, corresponding to thermostat malfunctioning and leaky ducts, can be accountable for any challenge that develops within the furnace.
Learn on for detailed info on widespread furnace issues that you could face and potential options.
1. Ignition Issues
If the furnace fails to ignite, it could possibly be attributable to a defective spark igniter, blocked fuel valve, or inadequate fuel provide. Newer furnace fashions don’t have a standing pilot for ignition; quite, they use electrical parts. In case of points with electrical ignition, your furnace may cycle on/off incessantly, produce little to no warmth, otherwise you may be coping with an overactive blower.
How you can Repair
- For older standard furnaces, flip off the furnace energy and examine the heating factor. If the igniter is cracked or broken, it received’t have the ability to generate sufficient warmth to ignite the gasoline. Contact an HVAC technician and substitute it.
- If the burner is soiled, it might trigger issues with ignition. Clear it with a smooth brush or vacuum cleaner to take away any grime or particles.
- Make sure the gasoline reaches the furnace. Test the gasoline line and the gasoline filter, and ensure they aren’t clogged.
- Confirm the ignition system. Be sure that the ignition system is working accurately. Test the circuit board, wiring, and different parts.
- For newer fashions, attempt changing the filters and checking the ability and fuel strains.
- Name a technician for an in depth checkup if these easy options don’t work.
2. Furnace Runs Non-Cease
In the event you discover your furnace is working repeatedly, there are two causes for that. Both your thermostat is about to fan mode, or there’s one thing unsuitable with the fan restrict management swap.
How you can Repair
Test your thermostat, and if it’s set to fan mode, the answer is to modify it to ‘auto’ mode. It will be certain that the fan solely runs when your system is heating.
The fan restrict management swap displays the temperature contained in the furnace and alerts it to show off when the set temperature is reached. If it’s not working, the furnace will carry on working. For troubleshooting, examine the fan motor swap. If it seems to be okay, reset it to repair the difficulty. If it seems to be broken, name a technician to exchange it.
3. Pilot Gentle Issues
Pilot gentle points are one of many widespread causes your furnace isn’t working. The sunshine can fully flip off, or you could discover steady flickering. The pilot gentle on fuel furnaces can exit attributable to drafts, debris-filled fuel tubes, or soiled pilot burners. A defective thermocouple, which is a sensor that measures temperature, also can trigger the fuel provide to close off. In the event you discover a yellow pilot gentle, it’s most probably attributable to extra carbon monoxide in your furnace.
How you can Repair
- Relight the pilot hearth if it had gone out. In case your furnace is working effective, the difficulty is resolved.
- If relighting doesn’t work, examine the furnace strain swap. This swap is designed to close off the fuel when the pilot gentle goes out. If the swap isn’t working, substitute it.
- Test the thermocouple; if it’s defective, substitute it.
- Make sure the fuel valve is open, and the provision line isn’t clogged or blocked.
- Lastly, examine the pilot gentle meeting. Make sure the pilot gentle is in good situation and the pilot gentle tube is evident of particles.
- Within the case of a yellow pilot gentle, it’s greatest to contact your native furnace technician, as carbon monoxide is harmful to cope with.
4. Thermostat Having Points
In case your furnace fails to make your property setting comfy, contemplate checking the set temperature in your thermostat. Generally, the thermostat can stop working and never ship the proper sign to the furnace. The unfastened wiring also can trigger points. Another excuse your thermostat is inflicting issues is an absence of upkeep. Mud and grime can intervene with the thermostat’s capacity to learn and reply to temperature adjustments. Incorrect thermostat location also can compromise the effectivity of the furnace.
How you can Repair
- Attempt resetting your thermostat if it’s exhibiting incorrect readings.
- In case your thermostat has bother reaching your set temperature, examine its calibration. Right here’s tips on how to calibrate your thermostat.
- To examine the unfastened wiring, detach the thermostat from the wall and look at the wire connections. Be sure that the wires popping out of the thermostat are correctly hooked up to their corresponding terminal on the thermostat.
- In case you have a battery-operated thermostat, examine the batteries and substitute them if wanted.
- The thermostat must be positioned away from drafts or direct daylight to get an correct studying.
- Test for grime and particles inside, and clear if wanted.

5. Soiled Air Filters
In case your furnace air filters are soiled or clogged, they will prohibit airflow, inflicting your furnace to work tougher. This may end up in overheating and eventual failure of the unit.
How you can Repair
If the filters are clogged or broken, they need to get replaced. Altering your filters each two weeks and changing them each 3-4 months is really useful.
6. Leaking Ducts
Leaking ducts may cause the furnace to run inefficiently. The air that’s meant to be heated will escape as an alternative, leading to wasted power and excessive payments.
How you can Repair
The easiest way to resolve this widespread furnace drawback is to seal the ducts correctly. This may be accomplished utilizing mastic or foil tape on high of the cracks and gaps. You may also have knowledgeable HVAC technician examine and repair the leaks. In some instances, changing your entire duct system could also be vital.
7. Thermostat and Furnace Are Mismatched
In case you have put in a thermostat that’s incompatible together with your furnace, you’ll face working issues. Because of this, your furnace could overheat or underheat your property.
How you can Repair
- Test your thermostat guide to seek out out if the furnace is suitable with it or not.
- If the unsuitable kind was put in, substitute it with the proper mannequin.
8. Inadequate Warmth Output
Inadequate warmth output in a furnace is when it doesn’t produce sufficient warmth. Your furnace could cease producing warmth or blow cool air solely. This could occur for varied causes, a few of which could be taken care of at residence.
How you can Repair
- Be sure that the warmth registers are open.
- Test the thermostat settings for any potential adjustments.
- Confirm that the furnace has energy and is working.
9. Furnace Biking Issues
The biking points in furnaces embody quick biking, when the furnace activates and off too typically, or over-cycling when the furnace runs longer than vital. Over-cycling places additional pressure on the furnace’s parts, resulting in elevated put on and tear.
How you can Repair
- Clear or substitute the air filter repeatedly.
- Test the thermostat settings and calibrate them if vital.
- Look at the burners for correct operation and clear them if vital.
- Regulate the blower velocity to make sure correct air circulation.
- Guarantee satisfactory return air provide.
Blower Elements Malfunctioning
10. Frayed Blower Belt
The blower belt is part of the furnace that helps its fan to run easily. Over time, it might change into frayed attributable to on a regular basis utilization or could slip from its place. In case your motor belt malfunctions, you’ll hear a high-pitched squealing noise.
How you can Repair
It’s important to exchange it as quickly as potential. If the belt is left on this situation, it might trigger the furnace to overheat and trigger additional injury.
- Be sure that to purchase the proper measurement belt earlier than you begin the substitute course of.
- To switch the belt, you need to flip off the ability to the furnace.
- To entry the blower belt, you’ll have to take away the blower panel. Then use the wrench to loosen up the bolts and take away the previous belt.
- Put the brand new belt as a substitute, so it’s cosy.
- Lastly, reinstall the entry panel and activate the ability to the furnace.
11. Worn-Out Ball Bearings
With regards to sustaining your furnace, one a part of the blower mechanism that ought to all the time be checked for issues is the set of ball bearings. They will develop put on and tear over time. They will additionally change into broken if they aren’t correctly put in. If there are points together with your furnace’s ball bearings, you’ll hear a scraping sound coming from the system.
How you can Repair
Working your furnace whereas these bearings are failing will solely make issues worse, so flip off your system and get in touch with your furnace technician to exchange the ball bearings as quickly as potential.
12. Broken Blower Capacitor
The capacitor is sort of a battery to your furnace that gives power for it to operate. If the capacitor goes haywire, then the motor will draw an excessive amount of energy from the circuit board to operate correctly. This could result in an overload that forces breaker journeys and even wire shorts.
How you can Repair
Have an HVAC skilled take a look at the capacitor and examine the injury.
13. Noisy Furnace
In the event you hear unusual noises like pinging or popping, squealing, grinding, or rattling, it’s most probably an indication of an underlying furnace drawback. As an illustration, a squeaking noise normally signifies issues with the blower belt, whereas scraping noises level to broken blower bearings. Rattling noises in your furnace could be attributable to unfastened elements, worn-out bearings, clogged burners, or a cracked warmth exchanger.
How you can Repair
- Test the blower belt for put on or injury.
- Examine the blower housing and motor for any unfastened or broken elements. Tighten the unfastened screws and likewise oil the motor for lubrication.
- Examine the warmth exchanger for any cracks or blockages. Name an HVAC technician if repairs are wanted.
- Clear or substitute the filters, as a clog could also be making the noise.
Associated: Air Conditioner Noises: What Causes Them & How to Fix
14. Cracked Warmth Exchanger
The warmth exchanger separates the flame from the air. In the event you don’t sustain with the furnace upkeep or when you set the temperature too excessive, the exchanger can crack. You’ll hear rattling noises if this occurs.
This crack permits doubtlessly harmful fumes, corresponding to carbon monoxide, to flee into the house as an alternative of being vented to the skin. This could create a doubtlessly hazardous scenario and must be addressed instantly.
How you can Repair
Sadly, this isn’t one thing that may be accomplished with out skilled help. You will want to have an HVAC individual are available in to examine the furnace and substitute the warmth exchanger if vital.
15. Gasoline Valve Malfunction
A defective fuel valve can result in varied points together with your furnace, together with inefficiency, extreme noise, and even security hazards. As well as, it might trigger the furnace to not ignite or warmth correctly. This may be harmful as it might result in a fuel leak or an explosion.
How you can Repair
- Flip off the electrical energy to the furnace.
- Find the fuel valve and shut it off.
- Take away the entry panel from the furnace.
- Examine the fuel valve for any seen indicators of injury.
- If the valve is broken, substitute the valve with a brand new one.
- Reattach the entry panel and switch the ability again on.
- Activate the fuel valve and examine for any leaks.
- If there are not any leaks, reset the furnace and take a look at the system.
16. Soiled Burners
Soiled burners may cause a number of points for a furnace. First, they will scale back the furnace’s effectivity, inflicting it to run longer and price extra. As well as, soiled burners may cause the furnace to supply soot, which might accumulate within the ducts and vents and result in well being dangers. They will additionally trigger the furnace to overheat, severely damaging the system.
How you can Repair
- Find the burners and clear them utilizing a vacuum cleaner to take away mud and particles.
- Subsequent, be certain the burner ports are clear and unclogged. If the ports are clogged, use a wire brush or pipe cleaner to clear them.
- As soon as the burner ports are clear, use a compressed air canister to blow out any remaining particles.
- Test that the burner is adjusted accurately and that the flame is burning blue. If the flame just isn’t burning blue, regulate the burner.
17. Burning Odor
Chances are you’ll discover a bizarre burning scent while you first flip in your furnace firstly of winter. That is normally attributable to layers of mud burning off because it heats up, and this scent ought to dissipate inside an hour. Nonetheless, if any sturdy odors persist for just a few days, it signifies a significant issue.
A moldy scent signifies the expansion of mildew or mildew contained in the furnace. A metallic or fuel scent alerts a fuel leakage, and in that case, instantly flip off the fuel valve and name for skilled assist. Open all of the home windows and evacuate your property.
Associated: 6 Reasons Why Your HVAC Smells & The Best Solutions
18. Soiled Flame Sensor
A unclean flame sensor may cause a furnace to malfunction by interfering with the furnace’s capacity to sense the presence of a flame. The flame sensor is a small probe close to a furnace’s burner. It acts as a security gadget to make sure the furnace is working accurately and isn’t producing harmful ranges of carbon monoxide. Nonetheless, when the flame sensor is soiled, it might’t precisely sense the presence of a flame, ensuing within the furnace not working correctly or not working in any respect.
How you can Repair
- Shut off the ability to the furnace.
- Take away the flame sensor from the furnace.
- Use an emery fabric or metal wool to scrub the sensor, eradicating any grime or particles.
- Dip the flame sensor in heat water and a gentle dish cleaning soap resolution.
- Gently scrub the sensor with a smooth brush or fabric to take away any remaining grime.
- Rinse the flame sensor with clear water and dry it with a smooth fabric.
- Reinstall the flame sensor and activate the furnace.
19. Water Pooling Across the Furnace
Excessive-efficiency furnaces have condensation pipes that may change into clogged or develop a leak. This could trigger water to pool round a furnace.
How you can Repair
- Test the slope of the ground to be sure that the ground across the furnace is sloping away from it in order that any water that accumulates close to it might naturally drain away.
- Examine the condensate line from the furnace to make sure it’s not clogged and draining accurately.
- Set up a sump pump. If the water continues to be pooling across the furnace regardless of the above steps, you could want to put in a sump pump to assist pump the water away from the furnace.
20. Clogged Exhaust and Consumption Vents
Clogged exhaust and consumption vents are widespread furnace issues. On this case, air received’t have the ability to stream freely, inflicting the system to change into inefficient and presumably even break down. Clogged vents could be attributable to varied issues, together with grime, leaves, snow, or furnishings items positioned in entrance of the vents.
How you can Repair
- Test all the within vents for any obstruction which may be stopping warmth stream. For instance, a furnishings piece or a curtain could impede the vents. Transfer them apart to repair the difficulty.
- Go outdoors and examine the exhaust vents for blockage. Search for corroded or rusted vents. If they’re broken, the furnace technician must be referred to as for a substitute.
- Test for blockages corresponding to leaves or ice if there isn’t a injury. Take out the leaves and clear the vents. If snow is obstructing the vents, shovel the ice after which clear them.
- After cleansing the exterior blockages, examine the within of the vents and search for soot or particles. Clear the within with a brush or fabric piece if required.
Often Requested Questions
Listed below are some widespread furnace issues FAQs that you simply may be wanting a solution for:
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Can an Outdated Furnace Trigger Well being Issues?
Sure, older furnaces could trigger well being issues as a result of launch of pollutants into the air. For instance, poorly maintained furnaces produce carbon monoxide, which is a colorless and odorless fuel that causes critical well being issues. Moreover, older furnaces could also be unable to filter out particles like mud, pollen, and pet dander which can lead to allergic reactions and bronchial asthma.
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What Issues Can a Soiled Furnace Filter Trigger?
A unclean furnace filter may cause a variety of issues, together with an inefficient furnace, hot or cold spots, elevated power prices, poor indoor air quality, clogged and soiled air ducts, and a excessive threat of furnace breakdowns.
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Do Excessive-Effectivity Furnaces Have Extra Issues?
Excessive-efficiency furnaces are designed to be extra dependable than conventional furnaces and have fewer restore points. They’re additionally extra power environment friendly, which might save you money on your heating bills.
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What Can Trigger Issues With 2-Stage Furnaces?
Potential issues with two-stage furnaces embody a blocked condensate line, clogged air filter, defective flame sensor, low refrigerant ranges, defective strain swap, and defective inducer motor. Moreover, points with the thermostat, corresponding to incorrect wiring or an previous, malfunctioning mannequin, may cause issues with two-stage furnaces.
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Who to Name For Furnace Issues?
It’s best to contact an authorized HVAC technician or contractor to diagnose and restore any furnace points. Seek for the very best HVAC technicians in your space and ebook an appointment.
When Do You Name an HVAC Technician?
In case you have the set of experience and an applicable toolkit, the directions above will help you tackle a number of challenges highlighted above. If that isn’t the case, you possibly can positively DIY just a few issues and depart difficult issues with an knowledgeable. DIY furnace issues can embody issues like changing air filters, cleansing parts, or checking for blockages. Points that may want an HVAC embody a damaged furnace fan, a malfunctioning thermostat, or a defective ignition system. If you’re uncertain of the reason for the issue or don’t really feel comfy trying a restore, it’s all the time greatest to name an HVAC technician.
Listed below are just a few points you possibly can deal with your self and some that must be assigned to a technician.
DIY furnace issues:
- Changing the furnace filter.
- Cleansing the blower meeting.
- Checking {the electrical} connections.
- Testing the thermostat.
Name an HVAC technician:
- If the furnace just isn’t igniting or not producing warmth.
- If the furnace is creating unusual noises or smells.
- If the furnace just isn’t biking accurately.
- If the furnace is leaking or not working accurately.
Reclaim Your Consolation With A Furnace Restore
Furnaces are an integral a part of home heating systems. They’re accountable for offering the perfect temperature in winter, and if they aren’t working correctly, it might compromise effectivity in addition to your consolation. Widespread furnace issues embody blocked or soiled air filters, malfunctioning thermostats, defective blower motors, and leaking ducts, amongst many others. These furnace issues can result in spiked payments and uneven heating.
Therefore, it’s crucial that after you discover any irregularity together with your furnace, you don’t brush it off. Slightly take motion for it as quickly as potential. You by no means know it may be an indicator of one thing a lot worse brewing in your furnace. Attain the basis of the issue and consider when you can deal with the difficulty your self or require skilled help.
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