Solved: Furnace Is Leaking Water and 8 Other Heating Issues

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

Regardless of the problem, learning 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 watching 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 Prudhom Mechanical. We can accurately diagnose the issue and execute 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 completely draining away. This might be due to a plugged condensate drain line or a failing condensate pump. Another likely cause of water leakage from a furnace is a cracked heat exchanger, which can be responsible for water—as well as dangerous gases—leaking out of the furnace.

It is necessary to deal with water leaks immediately to prevent additional damage to your furnace. Consulting with a professional HVAC technician like the crew at Prudhom Mechanical 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 blocked air filter, or a malfunctioning heating element. It also may be your furnace is overheating and shutting off as a safety measure.

If your furnace will not blow hot air, it's better to contact a professional HVAC specialist to diagnose and fix the problem. They can give an accurate assessment and recommend the correct solution.

3. My Furnace Struggles to Keep Up

A widespread reason your furnace isn’t keeping up on a cold day is that your home is lacking insulation, which can lead to heat loss and lower efficiency. Another reason your furnace is having difficulties is because it’s not powerful enough for your home, so it can’t make enough heat to adequately warm the space. A malfunctioning thermostat or ductwork problems can also result in inconsistent heating.

To deal with this, first look at 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 calling an experienced HVAC company, such as Prudhom Mechanical, who can assess your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or modifying your thermostat settings.

4. My Furnace Is Not Working

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

If there is power but no heat, the problem may be with the ignition system or gas supply. In that case, it's better to consult a knowledgeable HVAC technician 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 as opposed to running in regular cycles like it should. This can result in inefficiency, higher energy bills and potential damage to your heating system.

If you suspect your furnace is short cycling, the first step is to check your unit’s air filter. Filters should be switched out regularly to ensure air flow, so if your furnace air filter is clogged with debris you should exchange it for a clean one—and be sure it is pointing in the right direction. If that doesn’t do the trick, look at your thermostat and verify  it’s set right and the batteries are good.

If those two things don’t work, it’s a good idea to call experts like the crew at Prudhom Mechanical. Quick professional attention will help restore the proper functioning of your furnace and reduce the chance of 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 symptom of an issue with the electrical parts or the blower motor. Therefore, if you notice your furnace making a humming noise, it is crucial to take action.

If the noise doesn't go away, it is best to  contact a professional HVAC technician.

7. My Furnace Is Noisy

If your furnace is making a consistent loud noise, it's important to handle the issue quickly to prevent further damage or potential safety concerns.  One common problem that causes this 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 emit a squealing or rattling noise.

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

8. My Furnace Can't Turn On

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

If those steps don’t do the job, phone an expert for furnace repair.

9. My Furnace Won't Ignite

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

Other common causes of a furnace not igniting are a faulty igniter or nonfunctional flame sensor. Symptoms of these include the furnace continuously attempting to ignite without success, a lack of heat production or the furnace is making a burning or gas smell. Both of these issues can be easily addressed by HVAC pros like the team at Prudhom Mechanical.