24/Hour Emergency Service

24/Hour Emergency Service

Furnace Repair

A furnace that fails to start, cycles on and off repeatedly, or produces weak heat needs professional diagnosis. Furnaces contain gas valves, ignition systems, heat exchangers, blower motors, and electronic control boards that all work together. A failure in any one component affects the entire system. Common furnace problems include:

Ignition failure

Modern furnaces use hot surface igniters or direct spark ignition to light the burners. A cracked igniter, faulty flame sensor, or malfunctioning control board prevents the burners from lighting. The furnace may attempt to ignite, fail, and lock out after several tries.

Heat exchanger cracks

The heat exchanger separates combustion gases from the air circulating through your home. A cracked heat exchanger can allow carbon monoxide to enter the airstream. This is a safety concern that requires immediate attention. Full Nelson inspects heat exchangers visually and with combustion analysis during service calls.

Blower motor failure

The blower motor pushes heated air through the ductwork. A failing motor may run at reduced speed, produce unusual noises, or stop working entirely. Capacitor failure is a common related issue that prevents the blower from starting.

Flame sensor fouling

The flame sensor confirms that the burners have lit. When the sensor is coated with carbon buildup, it cannot detect the flame. The control board shuts down the gas valve as a safety measure, and the furnace cycles off shortly after lighting.

Thermostat issues

A miscalibrated or failing thermostat may not signal the furnace to start, may call for heat at the wrong times, or may cause short cycling. Sometimes the problem is wiring rather than the thermostat itself.

Draft inducer motor failure

The inducer motor vents combustion gases through the flue. If it fails, the pressure switch will not close and the ignition sequence will not start. The furnace makes no attempt to light.

Full Nelson technicians carry common furnace repair parts on service vehicles and complete most repairs in a single visit.

Furnace Replacement and Installation

Furnaces typically last 15 to 25 years depending on the model, usage, and maintenance history. When a furnace reaches the point where repair costs are mounting and reliability is declining, replacement is the more cost-effective path forward.

Signs that furnace replacement should be considered:

Full Nelson installs gas and electric furnaces sized to your home’s heating load.

AFUE (Annual Fuel Utilization Efficiency) measures what percentage of the fuel a furnace converts into usable heat. A furnace with 96% AFUE converts 96 cents of every dollar spent on gas into heat. The remaining 4 cents goes up the flue as exhaust. Current minimum federal standards require 80% AFUE for non-weatherized gas furnaces. High-efficiency condensing furnaces achieve 90% to 98% AFUE.

Upgrading from an older 80% AFUE furnace to a 96% AFUE model reduces gas consumption by roughly 20% for the same amount of heat output.

Full Nelson evaluates your existing ductwork, gas supply, electrical connections, and venting before installing a new furnace. We perform a heating load calculation to determine the correct furnace size, install the equipment, connect gas and electrical, run the flue, and test the system through multiple heating cycles. We verify temperature rise across the heat exchanger, check combustion performance, and confirm the thermostat controls the system correctly.

Heating Maintenance

Heating maintenance tasks include:

These maintenance items come directly from Full Nelson’s published seasonal HVAC maintenance checklist.

Why Full Nelson