Solved: Furnace Is Leaking Water and 8 Other Heating Issues

Whether it’s a leaky furnace or if you flick the switch to power up your heating system when it gets chilly and it won’t start, common furnace problems can impact your home at any moment.

Regardless of the cause, knowing how your heating system works and a little bit about some common furnace problems is essential in deciding whether you can troubleshoot on your own or if you need professional assistance. By observing 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 unsure about the problem or aren't equipped with the necessary skills and tools, it's best to call an experienced HVAC company like Bigfoot Mechanical. We can accurately identify 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 frequent heating problems:

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 may be due to a blocked condensate drain line or a failing condensate pump. Another possible cause of water leakage from a furnace is a cracked heat exchanger, which can result in water—as well as dangerous gases—coming out of the furnace.

It is important to deal with water leaks promptly to prevent more damage to your furnace. Contacting a professional HVAC technician like the crew at Bigfoot Mechanical is recommended to diagnose and resolve the issue effectively.

2. My Furnace Blows Cold Air/Not Blowing Hot Air

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 plugged air filter, or a malfunctioning heating element. It also may be your furnace is overheating and shutting off as a safety mechanism.

If your furnace won’t blow hot air, it's best to contact a skilled HVAC technician to diagnose and fix the problem. They can offer an accurate assessment and recommend the appropriate solution.

3. My Furnace Can't Keep Up

A frequent reason your furnace isn’t keeping up on a cold day is that your home lacks insulation, which can cause heat loss and reduced efficiency. Another reason your furnace is struggling is because it’s too small for your home, so it can’t make enough heat to adequately warm the space. A defective thermostat or ductwork problems can also result in uneven heating.

To correct this, first check your home’s insulation level and make sure it’s enough to insulate your home. Also, examine the thermostat to ensure it’s set right and the batteries are working.

If the problem continues, consider contacting an experienced HVAC company, such as Bigfoot Mechanical, who can inspect your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or adjusting your thermostat settings.

4. My Furnace Isn't Running at All

If your furnace is not working, there are a couple of steps you can take to troubleshoot before phoning a professional. Check if the thermostat is set right and the batteries are not dead. If the furnace still doesn't power on, check the circuit breaker or fuse box to ensure power is reaching the furnace.

If there is power but no heat, the problem may lie with the ignition system or gas supply. In that case, it's best to contact a seasoned HVAC professional for diagnosis and repair.

5. My Furnace Short Cycles

If your furnace is short cycling, that means it is turning on and off multiple times at short intervals rather than running in regular cycles like it should. This can lead to inefficiency, more energy use and potential damage to your unit.

If you think your furnace is short cycling, the first step is to check your unit’s air filter. Filters should be switched out when they are dirty to ensure air flow, so if your furnace air filter is dirty you should exchange it for a clean one—and make sure it is pointing in the right direction. If that doesn’t do the trick, check your thermostat and verify  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 Bigfoot Mechanical. Quick professional attention will help restore the proper functioning of your furnace and prevent more 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 a malfunction with the electrical hardware or the blower motor. Therefore, if you detect your furnace making a humming noise, it is critical to take action.

If the noise doesn't go away, it is better that you  get in touch with a professional HVAC technician.

7. My Furnace Makes Loud Noises

If your furnace is making a persistent loud noise, it's important to address the issue promptly to prevent further damage or potential safety risks.  One common reason is a malfunctioning blower motor or fan, which can generate a grinding or screeching sound. Another possible cause is a loose or worn-out belt that may produce a squealing or rattling noise.

Due to the complexity of furnace systems and potential risks involved, it's better to get in touch with a heating and cooling specialist.

8. My Furnace Can't Turn On

If your furnace refuses to turn on, make sure the thermostat is set to the preferred temperature, is in heating mode and the batteries are good. Then, check if the circuit breaker or fuse that goes to the furnace is functioning properly. If these basic checks don't address the problem, you can inspect the furnace's power switch or emergency shutoff switch to make sure they're in the "on" position and weren’t accidentally turned off.

If those steps don’t get the job done, contact a heating specialist for furnace repair.

9. My Furnace Is on but Not Igniting

Similar to a furnace that will not on at all, a furnace that isn’t igniting can be the result of a plugged air filter or a tripped circuit breaker. So, checking out the air filter and assessing your circuit breakers are a good place to start.

Other potential causes of a furnace not igniting could be a faulty igniter or faulty flame sensor. Signs of these include the furnace continually 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 very easily solved by HVAC professionals like the team at Bigfoot Mechanical.