Solved: Furnace Is Leaking Water and 8 Other Heating Issues

Whether it’s a leaky furnace or if you flip the switch to turn on your heating system in the fall and it won’t start, common furnace problems can affect 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 crucial in deciding whether you can troubleshoot on your own or if you need professional assistance. By watching the furnace's behavior, listening for peculiar noises and checking for signs of damage or blockage, you can narrow down the possible causes.

If you're not sure about the problem or lack the necessary skills and tools, it's best to call a professional HVAC company like Patterson & Stirling. We can accurately diagnose the issue and complete the required repairs or maintenance, so we can get your furnace working again ASAP.

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

1. The Furnace Is Leaking

A furnace can leak water for several reasons. One possibility is a condensate leak, where the water produced during the combustion process is not effectively draining away. This could be due to a clogged condensate drain line or a failing condensate pump. Another possible cause of water leakage from a furnace is a cracked heat exchanger, which can lead to water—as well as dangerous gases—leaking out of the furnace.

It is important to manage water leaks promptly to prevent more damage to your furnace. Consulting with a professional HVAC technician like the crew at Patterson & Stirling is recommended to diagnose and resolve the issue properly.

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

Some likely causes for a furnace blowing cold air or not blowing hot air could be a malfunctioning thermostat, a problem with the pilot light or ignition system, a clogged air filter, or a malfunctioning heating element. It also may be your furnace is overheating and shutting off as a safety precaution.

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

3. My Furnace Can't Keep Up

A widespread reason your furnace isn’t keeping up on a cold day is that your home lacks insulation, which can cause heat loss and decreased efficiency. Another reason your furnace is falling short is because it’s not big enough for your home, so it can’t generate 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 keep warm air in and cold air out of your home. Also, look at the thermostat to ensure it’s set right and the batteries are working.

If the problem lingers, consider consulting with an experienced HVAC company, such as Patterson & Stirling, 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 Won't Work

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

If there is power but your furnace won't blow hot air, the problem may be with the ignition system or gas supply. In that case, it's better to reach out to a seasoned HVAC technician for diagnosis and repair.

5. My Furnace Is Short Cycling

If your furnace is short cycling, it means it is turning on and off frequently at short intervals rather than running in regular cycles like it should. This can cause inefficiency, higher energy bills and potential damage to your heating system.

If you think your furnace is short cycling, the first step is to look at 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 clogged with debris you should exchange it for a clean one—and make sure it is pointing in the right direction. Second, check your thermostat and look to see if  it’s set right and the batteries are good.

If those two things don’t work, it’s best to call experts like the team at Patterson & Stirling. Prompt professional attention will help restore the proper functioning of your furnace and avoid more complications and high energy bills.

6. My Furnace Is Making a Humming Noise

When your furnace is making a humming noise, it often is an indication of a malfunction with the electrical components or the blower motor. Therefore, if you hear your furnace making a humming noise, it is important to take action.

If the noise persists, it is best to  contact a professional HVAC technician.

7. My Furnace Is Making a Loud Noise

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

Given the complexity of furnace systems and potential risks involved, it's best to consult 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 right temperature, is in heating mode and the batteries are functioning. Then, check if the circuit breaker or fuse that goes to the furnace is functioning properly. If these basic checks don't take care of the problem, you can check 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 a professional for furnace repair.

9. My Furnace Is Not Igniting

Much like a furnace that will not on at all, a furnace that isn’t igniting can be caused by a dirty air filter or a tripped circuit breaker. So, inspecting the air filter and looking over your circuit breakers are a good place to start.

Other likely causes of a furnace not igniting include a faulty igniter or faulty flame sensor. Symptoms of these include the furnace continually attempting 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 repaired by HVAC professionals like the team at Patterson & Stirling.