HVAC systems are major pieces of equipment in your home, and important for your year-round comfort and health. And yet, we don’t really give our heating and cooling systems much thought until something goes wrong. Here are three of the most common heating problems and what might be causing them.


My Furnace Won’t Start

When your furnace won’t ignite, the first things to check are that the air filter is still clean and that the power and the gas supply to the furnace are connected.

From there, if your furnace commences the start cycle, but then does not fire up, it could be that your sensor or ignitor is dirty or damaged and needs to be either cleaned or replaced. These are not necessarily DIY fixes, but they can be if you are comfortable with it.

The flame sensor takes care of igniting and maintaining the flame in your furnace. It’s not uncommon for a sensor to get dirty from carbon buildup or other particles within its enclosed space, and it does require periodic cleaning. If you feel confident to do this yourself, make sure the furnace is turned off, and it’s not a bad idea to switch off the breaker just to be safe. You’ll find the sensor by looking for the metal rod in the path of the burner with a wire attached to it. See if you can remove the sensor. This is generally done by removing the screws and pulling off the wire. It can be cleaned with sandpaper or steel wool, and then screwed back into place and the wire reattached.

The furnace ignitor is responsible for starting up the furnace, as its name implies, and sometimes needs to be replaced. To do this, as with the sensor, make sure the furnace is completely off before doing anything. The ignitor is usually found near the center of the burners. Unscrew it, be careful to see where and how it fits, and then screw the replacement ignitor into place.

If you are not 100% sure of what’s causing the problem, or unsure about doing these jobs yourself, it should be quick and inexpensive to have an HVAC professional drop by and do it for you as part of your system’s routine maintenance.


Why Is My Furnace Leaking?

Nowadays most of us have either a standard gas furnace or a newer high-efficiency gas furnace, and each has different causes for leaking.

A standard gas furnace doesn’t leak that often. If you have a humidifier built into your central heating system, that could be a likely cause of leaking water. The other cause could be an incorrectly installed flue or exhaust pipe. If that flue is faulty or improperly installed, it can cause heat to be trapped. This heated air will eventually cool and any vapor will convert to liquid, which will then go down into the heater or onto the floor. If you haven’t already guessed, this can cause significant damage to your furnace, and it’s not something you can fix yourself. Call a professional HVAC tech right away.

If you have a more modern, high-efficiency gas furnace, there are a different set of causes for leaks. These furnaces use a method to create heat where there is a small timing break in between the actions, during which the air in the furnace is allowed to cool, and that creates some condensation. This condensation is a normal part of the process and is routinely disposed of by the furnace drain system. Sometimes, you’ll have leaks if the drain line is clogged or damaged, or if a heat exchanger is not working correctly. This is less serious than leakage in a standard-type furnace, but still something you should get fixed by a professional.


There Are Strange Noises Coming From My Gas Furnace!

Cartoon of a smiling furnace with arms outstretched and a cozy orange fire glowing in the grate.

Unusual noises coming from your furnace can be very annoying, at the least. And if you don’t know what’s causing them, there is the worry and concern as to whether the heating might either shut down or blow up at any moment! Here’s a little rundown on these common noises. Except for number 1, most noises will require a professional HVAC technician to diagnose and repair them.


Noise #1: Whistling

This is a simple one, and usually due to a dirty and clogged air filter, which causes the fan to suck air from different directions and produce a whistling sound in the process. If it keeps up after changing the filter, then it could be due to leaks in the ductwork, where the sheet metal joints are not fitting tightly enough. See the section on Duct Leaks here. (hyperlink to Uneven Heating Blog).


Noise #2: Banging or Thumping

This could be an unbalanced blower motor or wheel, gas buildup, ductwork problems, or any number of issues. These noises signal the need to call in your trusted repairman as quickly as you can.


Noise #3: Low Rumbling

This one is a little less scary. It could be a problem with your burner or a need for some routine maintenance care, but probably not something that is going to cause your furnace to break down in the next few minutes. However, it does indicate that all is not well, and you should get it checked as soon as possible.



Noise #4: Scraping or Clanking

A young Asian woman with a red and black plaid neck scarf has her hands on her head and is grimacing. It looks like either she has a headache, or she is frustrated by something and doesn’t know what to do.

This one gives me a headache just to think about it! If your furnace is making sounds like metal hitting metal or scraping together, it could be something serious like a broken blower wheel or motor mount, or a loose blower wheel clanking against the blower housing. This is one you’ll want to have taken care of right away, as letting this situation continue could cause serious damage.


Noise #5: Screeching and Squealing

These irritating sounds could be your furnace may be telling you that it needs lubrication. The culprit could also be a loose fan belt.




Oval-shaped logo that says, “DM Select. Heating.Plumbing.Cooling.

Looking for an HVAC and furnace repair company you can trust? With stacks of 5-star reviews and over 30 years of experience in the N. Virginia – Maryland – Washington D.C. area, DM Select Services is one of the area’s top-rated HVAC firms. We service both residential and industrial heating systems of all types, so no matter what noise problem you’re experiencing, our certified HVAC technicians can provide you with solutions. Your job will be completed quickly by our experienced technicians who care about your comfort and take pride in keeping a high standard of work. Contact us today at (703) 721-4844, or online to request service or get a free quote and see our special offers.