The furnace that sat quiet all summer
A gas furnace spends months doing nothing, and the first real cold snap is when its weak parts show. The usual story is simple: the thermostat calls for heat, the blower stays silent or runs on cold air, and the house keeps dropping. Sometimes the furnace starts, runs for a minute or two, and shuts off again before the rooms warm, over and over through the night.
That start-and-stop pattern is called short cycling, and it points at a short list of suspects: a dirty flame sensor that cannot confirm the burner is lit, a clogged filter that lets the furnace overheat and trip its safety, or a vent problem that keeps the exhaust from clearing. A furnace that blows cold air while the burner is off is a different fault, often a failed igniter or a gas supply that never opened.
Gas furnaces do not belong in a do-it-yourself weekend. If you smell gas, leave the house and call your gas utility first. For everything else, call Johnson at (864) 579-3247, with emergency service available after hours and on weekends.
Gas in, spark, flame, exhaust out
A tech works the furnace in the order it fires. Gas supply and the gas valve first, then the igniter, which is a fragile part that cracks with age and is one of the most common reasons a furnace goes dark. Next comes the flame sensor, a thin rod in the burner flame that should be wiped clean or replaced if it has gone dull, because a sensor that cannot see the flame will shut the gas off a few seconds after it starts.
The inducer motor draws exhaust out through the vent, and a pressure switch confirms it is moving air before the burners are allowed to run. The filter and the blower get checked in the same pass, along with the vent pipe itself for blockages or loose joints.
A heat exchanger inspection matters most on older furnaces. That sealed metal chamber keeps combustion gases separate from the air your family breathes, so any crack in it changes the repair-or-replace answer on the spot.
A new furnace, sized to the house
When a furnace is worn out or the repair costs more than it has left to give, replacement starts with sizing. A furnace that is too large heats in short bursts and wears itself out cycling, and one that is too small never catches up on the coldest mornings. Johnson looks at the house, the existing ductwork and the venting before recommending anything.
Quotes on new systems are free, and financing is available. Johnson features Armstrong Air products and services all brands, so a furnace from another maker can still be repaired without being replaced. Cash, check, Visa and Mastercard are accepted.
