New York State • Gas Furnace Repair

Gas Furnace Repair in New York

A gas furnace that will not light, shuts off early, or smells of gas needs a careful diagnosis. This page explains the gas-side faults, the safety checks, and what a repair visit covers.

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Gas furnaces heat most New York homes that sit on a gas main, and their faults follow the gas: ignition, valve, flame sensor, and venting. When a caller says, 'No, it's gas furnace,' that one line sets the whole diagnosis - the technician expects a burner, a gas valve, and a flame sensor, not heating elements. This page walks through the gas-side faults in the order a technician checks them.

A gas furnace repair starts with the sequence the furnace follows every time it is asked for heat: the thermostat calls, the blower starts, the igniter glows, the gas valve opens, the burner lights, and the flame sensor proves the flame. When that sequence breaks, the furnace stops at the step that failed, and the fault is found by watching where the sequence stops. That is the whole method, and it works on every gas furnace.

Ignition and Pilot Problems

Ignition is the most common gas furnace fault. The igniter may be worn and glow without lighting the burner, the pilot may not stay lit, or the control board may never send the signal to ignite. The check is simple: watch the sequence and see where it stops. A worn igniter is tested and replaced; a pilot fault is traced to the thermocouple or the gas supply.

A furnace that lights and then goes out has a different fault from one that never lights. The flame sensor may be coated in soot and unable to prove the flame, so the control board shuts the gas off as a safety step. Cleaning the sensor fixes many of these calls, and the sensor is tested after cleaning to confirm it reads the flame through a full cycle.

Gas valve faults are rarer and more serious. A valve that will not open leaves the burner dark even when the igniter works. A valve that opens late or sticks can cause a hard light-off with a small boom. The valve is tested for voltage and for gas flow, and a valve that fails either test is replaced, because a gas valve is not a part to nurse along.

Gas Valve and Flame Sensor Faults

The gas valve and the flame sensor work as a pair, and a fault in either one stops the heat. The valve opens on the board's signal and meters gas to the burner; the sensor watches the flame and tells the board the burner is lit.

Flame sensor faults are usually simple. Soot coats the sensor rod, the rod's reading drops, and the board shuts the burner down. A cleaning and a test through full cycles often ends the call. When cleaning does not hold, the sensor is replaced.

Gas valve faults need a steadier hand. The technician checks the voltage at the valve, the gas pressure at the inlet, and the valve's response to the board's signal. A valve that receives the signal and does not open is done.

Gas Smell: What to Do First

A gas smell at a furnace is a safety call, not a repair call. 'We were smelling gas.' If you smell gas, do not light anything, do not flip switches, and do not search for the leak. Leave the house and call the gas utility or the fire department from outside.

A gas smell can come from a loose fitting, a cracked connector, or a valve that is not seating. 'So they've turned the gas off to the furnace' is what a utility crew does when it finds a leak: the gas is isolated at the unit until the fault is found.

The heat exchanger is checked on every gas smell visit. A cracked exchanger can push combustion gas into the air the home breathes, and a cracked exchanger means the furnace is not put back into service.

Oil Furnaces and Oil Burners

Many New York homes beyond the gas mains heat with oil, and an oil furnace behaves differently from a gas one. 'I have an issue with my oil furnace' is the start of most oil calls, and the fault is usually at the burner: a worn nozzle, a clogged filter, electrodes out of adjustment, or an oil line that has lost its prime.

Oil and gas differ in how they fail. 'once it gets under 40 degrees, then the oil furnace is supposed to kick on, and that's what's not happening' describes a dual-fuel home where the oil furnace should take over from the heat pump in the cold.

Oil heat is not rare in New York. In Cobleskill, oil heat runs in about 36 percent of homes, ahead of gas at about 15 percent, so oil knowledge is part of gas furnace work in much of the state.

Fuel type is worth stating at the start of the call. 'No, it's gas furnace.' That line tells the technician which system to expect and which parts to carry. A gas call brings igniters, flame sensors, and valves; an oil call brings nozzles, filters, and burner parts.

Gas Furnace Safety Checks

Igniter and pilot tested through full cycles.
Gas valve voltage and gas flow tested.
Flame sensor cleaned and tested.
Gas fittings checked and line tested for pressure.
Heat exchanger looked over for cracks.
Flue checked for blockage and corrosion.
Carbon monoxide safety controls tested.

Frequently Asked Questions

Why does my gas furnace light and then go out?

The flame sensor is the usual cause. When soot coats the sensor rod, it cannot prove the flame, and the control board shuts the gas off as a safety step. Cleaning the sensor and testing it through full cycles often fixes the fault, and a sensor that will not read is replaced.

What should I do if I smell gas near my furnace?

Leave the house at once without flipping switches or lighting anything, and call the gas utility or the fire department from outside. Call for furnace repair only after the home is declared safe and the gas fault is isolated.

How do I know if the problem is the gas valve or the igniter?

Watch the sequence: if the igniter glows and the burner never lights, the valve or the gas supply is the likely fault. If the igniter never glows, the fault is on the ignition side. A technician tests the voltage at the valve and the igniter to confirm.

Do you repair oil furnaces as well as gas furnaces?

Yes. Many homes beyond the gas mains heat with oil, and oil burner service covers the nozzle, filter, electrodes, and oil supply. A burner that will not fire is checked from the tank forward, and dual-fuel handoffs are tested too.

What causes a gas furnace to short cycle?

A coated flame sensor, a clogged filter, or an overheating limit switch are the usual causes. The technician watches a full heating cycle to see where it stops, then tests the part that should have acted at that point.

Areas We Serve

This service is available across New York State, including:

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