Whether it’s a leaky furnace or if you throw the switch to turn on your heating system in the fall and it won’t start, common furnace problems can strike your home at any moment.

Regardless of the problem, learning how your heating system works and a little bit about some frequent furnace problems is crucial in deciding whether you can troubleshoot on your own or if you need professional support. By monitoring the furnace's behavior, listening for strange noises and checking for signs of damage or blockage, you can narrow down the possible causes.

If you're uncertain about the problem or don't have the necessary skills and tools, it's best to call a professional HVAC company like Farnell Mechanical, Inc.. We can accurately diagnose the issue and perform the required repairs or maintenance, so we can get your furnace up and running ASAP.

Here's more about what causes a furnace to leak water and eight other prevalent heating dilemmas:

1. The Furnace Is Leaking

A furnace can leak water for many reasons. One possibility is a condensate leak, where the water created during the combustion process is not effectively draining away. This might be due to a blocked condensate drain line or a malfunctioning condensate pump. Another likely cause of water leakage from a furnace is a cracked heat exchanger, which can result in water—as well as dangerous gases—leaking out of the furnace.

It is imperative to correct water leaks quickly to prevent additional damage to your furnace. Contacting a professional HVAC technician like the crew at Farnell Mechanical, Inc. is recommended to diagnose and resolve the issue properly.

2. My Furnace Is Blowing Cold Air/Lack of Heat

Some possible causes for a furnace blowing cold air or not blowing hot air are a malfunctioning thermostat, a problem with the pilot light or ignition system, a blocked air filter, or a malfunctioning heating element. It is also possible your furnace is overheating and shutting off as a safety measure.

If your furnace won’t blow hot air, it's best to contact a professional HVAC tech to diagnose and fix the problem. They can give an accurate assessment and advise you on the proper solution.

3. My Furnace Is Not Keeping Up

A frequent reason your furnace isn’t keeping up on a cold day is that your home doesn’t have enough insulation, which can cause heat loss and reduced efficiency. Another reason your furnace is having difficulties is because it’s not powerful enough for your home, so it can’t produce enough heat to effectively warm the space. A defective thermostat or ductwork problems can also result in inconsistent heating.

To correct this, first look at your home’s insulation level and make sure it’s enough to insulate your home. Also, look at the thermostat to ensure it’s set right and the batteries aren’t dead.

If the problem won’t go away, consider calling an experienced HVAC company, such as Farnell Mechanical, Inc., who can inspect your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or modifying your thermostat settings.

4. My Furnace Isn't Running at All

If your furnace is not working, there are some steps you can take to troubleshoot before contacting a pro. Make sure the thermostat is set correctly and the batteries are fresh. If the furnace still doesn't start, check the circuit breaker or fuse box to make sure power is reaching the furnace.

If there is power but your furnace won't ignite, the problem may be with the ignition system or gas supply. In that case, it's a good idea to contact a seasoned HVAC technician for diagnosis and repair.

5. My Furnace Short Cycles

If your furnace is short cycling, it means it is turning on and off often at short intervals instead of running in regular cycles like it should. This can cause inefficiency, more energy use and potential damage to your furnace.

If you suspect your furnace is short cycling, the first step is to pull out your unit’s air filter. Filters should be switched out regularly to ensure air flow, so if your furnace air filter is plugged with dirt you should exchange it for a clean one—and make sure it is pointing in the right direction. Second, look at your thermostat and make sure  it’s set right and the batteries are good.

If those two things don’t work, it’s smart to call experts like the staff at Farnell Mechanical, Inc.. Quick professional attention will help restore the proper functioning of your furnace and prevent further complications and high energy bills.

6. My Furnace Won't Stop Humming

If your furnace is making a humming noise, it often is a sign of an issue with the electrical hardware or the blower motor. For this reason, if you notice your furnace making a humming noise, it is critical to take action.

If the noise persists, it is better that you  get in touch with a professional HVAC technician.

7. My Furnace Is Noisy

If your furnace is emitting a constant loud noise, it's important to handle the issue promptly to prevent further damage or potential safety hazards.  One common problem that causes this is a failing blower motor or fan, which can generate a grinding or screeching sound. Another common cause is a loose or worn-out belt that may produce a squealing or rattling noise.

Because of the complexity of furnace systems and potential risks involved, it's best to get a hold of a heating and cooling specialist.

8. My Furnace Is Not Turning On

If your furnace will not turn on, make sure the thermostat is set to the preferred temperature, is in heating mode and the batteries are functioning. Then, see if the circuit breaker or fuse controlling the furnace is working right. If these basic checks don't take care of the problem, you can examine the furnace's power switch or emergency shutoff switch to verify they're in the "on" position and weren’t accidentally turned off.

If those steps don’t work, call an expert for furnace repair.

9. My Furnace Is Not Igniting

Like a a furnace not turning on at all, a furnace that isn’t igniting can be caused by a clogged air filter or a tripped circuit breaker. So, checking the air filter and looking over your circuit breakers are a good place to start.

Other likely causes of a furnace not igniting could be a faulty igniter or malfunctioning flame sensor. Indications of these include the furnace repeatedly making an attempt to ignite without success, an absence of heat production or the furnace is making a burning or gas smell. Both of these issues can be simply addressed by HVAC specialists like the team at Farnell Mechanical, Inc..