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Furnace Repair Service in Concord

The short answer

Most furnace failures we see in Concord come from dirty flame sensors, failed igniters, pressure switch or inducer problems, clogged filters or a bad control board. We test the full start-up sequence, repair the failed part and check for safe venting.

Concord winters are mild by national standards, but the valley floor gets cold on clear December nights, and a furnace that quits at two in the morning is a real problem. Most gas furnaces here sit in a garage, a hallway closet or an attic, and many have been running quietly for a long time with little attention. EliteFlow HVAC Repair Service repairs gas and electric furnaces throughout Concord's 94518, 94519, 94520 and 94521 ZIP codes, about 13 miles up the road from our Danville shop. Here is how a modern furnace starts, where that sequence usually breaks, and how we decide between a repair and a replacement.

The start-up sequence, and where it fails

When the thermostat calls for heat, a furnace runs through a fixed chain of steps. Knowing that chain helps explain why a furnace will sometimes try, click and give up.

First the inducer motor clears the heat exchanger and proves draft through a pressure switch. Then the hot surface igniter glows, the gas valve opens, and burners light. The flame sensor has to confirm a flame within seconds or the board shuts the gas off. Once the heat exchanger warms up, the blower starts and pushes warm air through the ducts. A failure at any link stops the process, and many boards flash a code that points to which one.

  • Burners light, then shut off after a few seconds: usually a dirty flame sensor.
  • Inducer runs, nothing else happens: a blocked vent, a cracked pressure hose or a failed pressure switch.
  • No glow at the igniter: a cracked igniter or a board that is not sending power.
  • Burners stay lit but no air comes out: blower motor, capacitor or a control fault.
  • Furnace shuts off on high limit: restricted airflow from a filter, closed registers or crushed ducts.

Safety first with gas heat

If you smell gas, leave the house and call the gas utility from outside before calling anyone else. If a carbon monoxide alarm sounds, get everyone out and let the fire department check the home. These are not situations to troubleshoot.

On every furnace repair we check the venting path, look at the flame pattern and inspect what we can see of the heat exchanger. In older Concord garages, we sometimes find vent connectors that have separated, or storage pushed up against the furnace cabinet. Those are easy to fix once someone notices them.

Repair or replace an older furnace?

We will repair a furnace when the fix is reasonable and the equipment is sound. When a furnace is near the end of its life, needs a heat exchanger, or keeps failing in different places, we explain the tradeoffs clearly.

The Bay Area Air District rules matter here, but they are narrower than many people think. They do not require you to replace a working furnace. Under Rule 9-4, gas furnaces manufactured from 2029 must meet a zero-NOx standard, which in practice points toward heat pumps when a furnace is replaced after that date. If your furnace is already old, it is worth thinking ahead about whether the next system should be a heat pump, so that a midwinter breakdown does not force a rushed decision.

What a Concord furnace visit includes

We start with what you noticed: whether the furnace made noise, flashed a light, or blew cold air. Then we read the board's fault code if there is one and watch a full heating cycle from the call for heat to blower shutoff. That observation often reveals more than any single test.

Next come measurements. We check the igniter's resistance, the flame sensor's microamp signal, gas pressure at the valve, temperature rise across the heat exchanger, and the static pressure in the ducts. High static pressure is common in homes where a return was undersized from the start or where a newer, more restrictive filter was added later, and it quietly shortens the life of blower motors and limit switches.

Before we leave, you get a written note of what we found, what we replaced and anything we would watch for next season. If the furnace is serviceable but tired, we say so plainly instead of waiting for the next breakdown to bring it up.

Small habits that prevent winter calls

Change the filter on a schedule that matches your home, more often with pets or during smoke events. Keep the area around a garage furnace clear of boxes, paint and gasoline. Run the heat for a few minutes in early fall, so a dusty burner or a weak igniter shows up before the first cold night instead of during it. A yearly check before winter also lets us clean the flame sensor and test the safeties. Homeowners in Clayton, Pleasant Hill and Walnut Creek get the same service.

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What to expect

How a visit goes

  1. Clear findings

    We show you the failed part or the reading that points to it, and explain what it means for the rest of the system.

  2. Choices, not pressure

    Repair, replace or wait and watch: you get the trade-offs of each and make the call yourself.

  3. Care for your home

    Shoe covers, drop cloths and a clean work area when we leave, whether the job was in the attic, garage or hall closet.

FAQ

Common questions

Why does my furnace light and then turn off?

That pattern most often points to a dirty or weak flame sensor. It can also come from a gas pressure or grounding issue, which a technician can test.

What does a burning smell at the start of the season mean?

A light dusty smell for a few minutes after months off is normal. A strong electrical or plastic smell, or one that does not fade, is a reason to shut the system off and call.

Do I have to replace my gas furnace because of the Air District rules?

No. The rules do not require replacing working equipment. They affect which furnaces can be sold and installed going forward.

Can you repair older furnaces with standing pilots?

Yes, as long as parts are available and the unit is safe. We will tell you if the condition of the furnace makes repair a poor investment.

How often should a Concord furnace be serviced?

Once a year in the fall is a sensible baseline, with filter checks every month or two during the heating season.

Do you serve all of Concord?

Yes. We cover 94518, 94519, 94520 and 94521, plus Pleasant Hill, Clayton, Walnut Creek, Lafayette and Moraga.

Tell us what your system is doing

Describe the noise, the smell or the temperature problem when you reach out, and we will schedule a technician with the right parts for your equipment.

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