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Top 6 Furnace Problems & How to Fix Them | Fred's Home Services
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Top 6 Furnace Problems & How to Fix Them | Fred's Home Services

Top 6 Furnace Problems & How to Fix Them

Woman freezing at home, furnace not working problem

Now that the Cleveland winter is upon us, we're all switching out HVAC systems from air conditioning to heat in order to stay warm and cozy. You hardly notice your furnace operating in the background until it starts to malfunction. Although most furnaces are designed to last for decades, chances are that yours will experience some mechanical issues as the years go by. In this article, we'll consider six common furnace problems that homeowners experience in winter and how to address them.

1. Your Furnace is not turning on.

While it may seem like a no-brainer, check that your thermostat is on and at the proper settings. If it's set to "OFF" or "COOL", then the furnace will stay off. If your thermostat is on and set to "HEAT" but the temperature is too low, then your furnace will not turn on until the thermostat registers that low temperature. During the winter, experts recommend setting your thermostat to 68°F while you're home and lowering it to 57-62°F while you're away or sleeping. These temperature settings will help maintain a comfortable, energy-efficient environment.

If you adjust your thermostat settings and your furnace still doesn't turn on, there are several other potential causes:

Loose or removed access panelIf the access panel is removed, a safety switch on the furnace door will prevent the fan and burner from coming on. The door must be securely in place in order for the safety switch to be activated and the furnace to operate.

  • If the access panel is closed all the way and the furnace still won't turn on, then you may have a faulty safety switch that needs to be replaced. In that case, contact Fred's Home Services to have a furnace expert inspect it.

Circuit breaker is turned off. If your circuit breaker is shut off, then your furnace won't turn on. Check your circuit breaker panel to make sure that all of the switches for your HVAC system are set to "ON". 

  • If any of these circuit breakers are tripped, reset them only once. Never tape a circuit breaker on! This creates the risk of damage to your HVAC system or an electrical fire. If the circuit breakers keep tripping and your furnace won't turn on, contact Fred's Home Services.

Standing pilot light is extinguished. If there is a disruption in fuel supply and your furnace doesn't sense a flame, it will shut off. To reignite the pilot light, turn the gas valve to the "OFF" position and wait 5 minutes. Then turn the valve to the "PILOT" position and hold a flame to the pilot gas tube while pushing the reset button for about 30 seconds. If the pilot doesn't light on your first try, wait a few minutes and repeat the procedure, this time holding the reset button down for 45 to 60 seconds. Once the pilot is lit, turn the gas valve back to the "ON" position.

  • If the pilot light won't stay lit, there may be an issue with the thermocouple or ignition system. Contact Fred's Home Services for professional assistance.
  • On newer furnaces with the intermittent pilot (IP), the pilot turns on after receiving an electronic signal from the thermostat. If the IP doesn't turn on at all, contact Fred's Home Services.
  • On newer, highly efficient gas furnaces with a hot surface ignitor (HSI), the IP can turn on but fail to keep the burners ignited. In this case, contact Fred's Home Services to have the HSI replaced.

Dirty ignition sensor. A contaminated ignition sensor will not be able to sense a flame, therefore preventing the furnace from operating.

  • Cleaning an ignition sensor is best left to a trained HVAC professional, so contact Fred's Home Services if you have a dirty ignition sensor.

Drain (condensate) pan is full. The water that has been removed by your HVAC system should automatically be pumped or drained out. If the drain pan is full of water, it will trigger a float switch that prevents your furnace from turning on as a safety precaution. If that's the case, empty the drain pan and make sure that the pump line is clear and working properly.

Clogged air filter. A badly clogged air filter may trigger a safety feature that prevents your furnace from turning on. Check your air filter and replace it if it's dirty.

Lack of fuel. Obviously, if your furnace is not getting the fuel it needs to function, it won't turn on. You can check your fuel supply by testing other gas- or propane-powered appliances in your home. If none of them are working properly, contact your gas or propane company.

2. Your furnace is not producing any heat.

Again, start by checking your thermostat. Make sure that your thermostat is set to "HEAT" and not "FAN". The fan setting will blow unheated air through your vents. Also double check that your wall and floor vents are open. Closed vents will naturally prevent the heated air from warming your home and can even cause heat to build up in your furnace and shut it down automatically as a safety precaution.

If your thermostat is set up properly and you have confirmed that your vents are open but your furnace is still not circulating warm air, there are a couple other possible causes.

Dirty burners. Dirty burners can't release enough gas to create combustion, which means your furnace won't produce heat. Clean, healthy burners will be lit with efficient blue flames. Yellow or orange flames indicate that the burners are contaminated with debris. Dirty burners can also produce a loud booming rumble when they try to ignite.

  • If your burners are dirty, we strongly advice against cleaning them yourself. Contact Fred's Home Services and leave it to our furnace experts.

Clogged air filter. An overly clogged air filter restricts airflow and will cause the heat exchanger to overheat and shut off before it can even warm the air. Check your air filter and replace it if it's dirty.

3. Your furnace is not producing enough heat.

The most common cause of poor furnace performance is a clogged air filter. Dirt and debris that build up on the filter will force your HVAC system to work harder without pushing much heat into your home. The restricted airflow could also cause your furnace itself to overheat and shut off prematurely. Not only will your house be chilly, but your energy bills will skyrocket and you'll shorten the lifespan of your furnace. Check your air filter and replace it if it's dirty. If changing the air filter doesn't fix the problem, contact Fred's Home Services for expert advice.

4. your furnace frequently turns on and off.

During a short cycle, your furnace will run for a couple of minutes and then shut off again without ever reaching your thermostat's set temperature. Oftentimes, the cause of frequent cycling is a clogged air filter, since restricted airflow builds up pressure and heat inside the furnace and can trigger the safety switch to turn off the furnace. Check your air filter and replace it if it's dirty. If you replace the filter and your furnace is still experiencing frequent cycling, this could indicate a serious issue with the blower motor and belts. In that case, contact Fred's Home Services as soon as possible.

5. the blower is constantly running.

First, make sure that your thermostat is set to "AUTO" and not "ON". The "AUTO" mode shuts off the furnace once the thermostat senses that the set temperature has been reached. Other modes will run the fan continuously, regardless of the room temperature. If your thermostat is set to "AUTO" at a reasonable temperature but continues to run without letup, then the furnace limit switch may be faulty. Contact Fred's Home Services to have an HVAC professional reset or repace a faulty limit switch.

6. your furnace is noisy.

 Pay close attention to the type of sound coming from your furnace. Different noises indicate different mechanical problems.

  • Rattling or knocking: Loose panels or other external components on your furnace may simply need to be tightened.
  • Loud rumbling: There may be fuel left in the combustion chamber after the system has been shut off, or dirty burners are struggling to ignite. In either case, shut off your furnace and contact Fred's Home Services to inspect it.
  • High-pitched squealing or shrieking: The blower belt — which connects the motor to the fan — has slipped and needs to be put back in place or is worn and needs to be replaced. Contact Fred's Home Services to have an HVAC expert perform the repair.
  • Grinding or scraping: This means the furnace's ball bearings have worn out. You should turn off your furnace immediately and contact Fred's Home Services to get them replaced as soon as possible.

If simple DIY troubleshooting fails to identify or fix problems with your furnace, contact Fred's Home Services today for expert furnace maintenance and repair service in Cleveland, Ohio.

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