Furnace and heating repair in Gibbstown, NJ

How a gas furnace starts, and where it stops

When the thermostat calls for heat, a gas furnace runs the same routine every time. The inducer motor clears the flue. A pressure switch confirms the draft. The ignitor glows, the gas valve opens, and a flame sensor proves there is a flame. After a short delay the blower pushes warm air into the ducts. A limit switch watches the temperature the whole time.

If any step fails, the control board stops and usually flashes a code on a small light inside the panel. Count the flashes before you call. That number, and the sticker that explains it, often tell the technician which part to bring.

Common stopping points:

• Flame sensor. A coated sensor cannot prove the flame, so the burners light and go out within seconds.
• Ignitor. Hot surface ignitors crack with age. The inducer runs, nothing glows, the furnace tries three times and locks out.
• Pressure switch. A blocked flue, a cracked hose or a failing inducer keeps the switch open.
• Limit switch. A clogged filter or closed registers starve the furnace of air and it overheats.

Oil furnaces are a different machine

About three in ten Gibbstown households heat with fuel oil, according to Census estimates for ZIP 08027. An oil furnace replaces the ignitor and gas valve with a fuel pump, a filter, a nozzle that sprays a fine mist, and an electrode spark. A cad cell watches for the flame and the burner's primary control shuts it down if none appears.

When an oil burner locks out, the red reset button on the primary control pops. Press it once. If the burner does not stay lit, stop: repeated resets can flood the chamber with oil. A clogged nozzle or filter, air in the line after the tank ran low, and a dirty cad cell account for many oil no-heat calls.

What a repair visit covers

The first visit is diagnostic. A technician confirms the thermostat is calling, then works through the sequence until it stops. Most contractors charge for that visit, and some credit it toward the repair. Ask which before the visit is booked.

A combustion check belongs on the visit too: carbon monoxide in the flue and draft at the vent, plus a smoke test on oil. If the heat exchanger is cracked, the conversation turns to furnace replacement.

Tune-ups before the season

The first frost at Philadelphia International Airport, the nearest NOAA normals station, comes around November 10 in a typical year. A burner that sat since April is most likely to fail on that first cold night. A fall service, with a new nozzle and filter on oil or a cleaned flame sensor on gas, moves that repair to a day when the schedule still has openings.

What to say when you call

• Gas or oil, and how old the furnace is
• What happens: nothing at all, lights then shuts off, runs but blows cold air
• The number of flashes on the board light, if you can see it
• Whether the reset button was pressed, and how many times
• The thermostat setting and the room temperature
• The address and ZIP code