Furnace Not Heating in Dublin

Furnace Not Heating in Dublin

A lot of Dublin housing is newer than the surrounding cities, so when one of those homes loses heat, the equipment usually is not old enough to be failing from age. The cause tends to be a control board fault, a smart thermostat that lost its wiring or its setup, or a clogged filter tripping the limit switch. Those are quick diagnoses and quick fixes.

Dublin's older core is a different story. Those homes run furnaces approaching replacement age, where a no-heat call is more likely a cracked igniter or a tired draft inducer. The age of the home changes what we expect to find before we even open the cabinet, so we ask about it when you call.

Either way, a furnace that quits is rarely a dead system. We see a lot of Nest and ecobee thermostats in Dublin's newer homes, and a fair share of winter no-heat calls turn out to be a thermostat or low-voltage wiring problem rather than the furnace at all. We check that first because it is cheap to rule out.

Common causes

Smart thermostat wiring or setup. We see plenty of Nest and ecobee installs in Dublin, and a missing C-wire, a dead battery, or a bad configuration will leave the furnace getting no call for heat. It reads on a service ticket like a furnace failure. We verify the thermostat is actually sending the signal before touching anything in the furnace.

Control board fault. On systems that are around a decade old, the integrated furnace control board can fail. It may lock out, throw a fault code, or stop sequencing the igniter and blower. We read the codes and test the board outputs rather than replacing it blind.

Dirty filter tripping the limit switch. A choked filter starves airflow, the heat exchanger overheats, and the limit switch shuts the burners off to protect the system. Common in homes where the filter has not been changed in a year. We restore airflow, reset the switch, and confirm the furnace cycles normally.

Cracked igniter on older core homes. Older homes around downtown Dublin run furnaces old enough that the hot surface igniter is the usual no-heat culprit. We test it for continuity and replace it, usually same visit, with the part priced on the estimate first.

Flame sensor fouling. Furnace lights then drops out after a few seconds. A carbon-coated flame sensor stops proving the flame and the board cuts gas. Cleaning usually restores heat. We replace it only if it is pitted past use.

Failed draft inducer. If the inducer motor will not spin up, the pressure switch stays open and the burners never light. We confirm the failure before quoting the motor on the written estimate.

How we diagnose it

• Because Dublin's smart-thermostat homes fail here often, the thermostat and low-voltage wiring get checked before we open the furnace, confirming there is an actual call for heat.
• We pull the control board fault codes and watch a full ignition sequence to see where it stalls.
• The filter and return airflow get inspected and the limit switch tested before we condemn any burner-side part.
• Igniter, flame sensor, and pressure switch each get metered to diagnose the exact failed component.
• On every gas furnace we run a carbon monoxide test and inspect the heat exchanger, then verify a complete heat cycle before leaving.

$75 diagnostic, credited toward any repair over $200. You get a written quote before any work begins.

Furnace Not Heating in Dublin: common questions

Nearby and related

Furnace Not Heating near Dublin: Pleasanton · San Ramon · Livermore .

This is usually a furnace repair in Dublin job. See our furnace repair overview or the Dublin service area.