When Your Heating System Goes Bump in The Night

Insane man screaming in bed

We may be close to Halloween, but spooky noises should not be coming from your heating system. Any kind of mechanical device will emit sounds as it operates, but clanging and banging should not be among them. The Roanoke heating specialists at Southern Trust Home Services can take care of whatever rattle, thump and boom is coming from your basement or mechanical room.


Your heating unit will heat either water or air to keep your home warm in the winter. Many noises are common, such as those from expansion and contraction of pipes and ductwork. One noise that you absolutely do not want to hear is a roaring noise that sounds like a freight train. That can mean a chimney fire — leave the house immediately and call the fire department.


The first thing to do is determine where the noise is coming from. Sometimes it’s obvious, such as banging pipes. Pipes make noise when the pipes and radiators contain air and not water. One way to tell is if the top of a radiator feels cool but the bottom is hot. That means air isn’t venting properly. It’s far more common for steam pipes to make noise, but we don’t have a lot of that type of heat in the Roanoke area.


Circulator pumps in hot water systems can be so quiet that you can’t hear them. Whining, buzzing or grinding noises are not good. If there’s air in the system, it may cause a loud vibrating noise from “cavitation” as the circulator tries to pump both air and water through it.


Ductwork can make a metallic sound often referred to as “oil-canning” as it expands from the force of the furnace fan moving hot air through it. The sound is annoying but not dangerous. If it’s so noisy that it’s disturbing your enjoyment of your home, we can fix it.


Some sounds indicate that some component of your heating system is about to break. If you hear a loud buzzing sound, that may indicate that an electrical component such as a relay or contactor is about to fail. Sometimes that kind of noise means something is loose and vibrating against part of the furnace. If you hear a screeching noise that’s not coming from trick or treaters, it could be the sign of a bad bearing in a fan or motor.


If you have an oil furnace or boiler, the unit will make fan noises from both the combustion air blower and from the furnace fan. You’ll also hear a fan noise from the draft inducer. There should not be whining, buzzing and rattling, especially from the burner.


You do not want to hear a bang when your oil burner fires. An oil burner sprays atomized oil particles through a hot ignition source. When the oil-fired equipment is properly maintained, the burner lights and the appliance heat your house. If it bangs, that means there’s unburned fuel accumulating in the combustion chamber. The worst-case scenario results in what’s called oil burner “puff back,” which means there’s a miniature explosion in your heating unit that sprays soot all over your house.


All heating systems will emit ticking, creaking and the occasional popping noise. Those are normal sounds from mechanical equipment operating and metal expanding and contracting. If your heating system, however, is making new, unusual and disturbing sounds, call the Roanoke heating specialists at Southern Trust Home Services at (540) 343-4348.

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