Furnace Repair in Garland, TX: No Heat, What Gets Checked, and Safety

Furnace repair in Garland starts with a simple question: is the furnace failing to heat, or is it unsafe to keep trying? Garland nights in a cold front are not long, but they are cold enough that a furnace which sat all summer has to light on the first try. Some no-heat calls are a filter, a thermostat, or a switch. Some are an igniter or a sensor. A few are a reason to leave the house. This page is how to tell those apart, and what a technician actually checks when you call.

If you smell gas (a rotten egg odor), stop reading and leave. Do not flip switches, use a phone inside, or relight anything. Call your gas utility or 911 from outside. If a carbon monoxide alarm sounds, or anyone has a headache, nausea, or dizziness that eases outdoors, get everyone out and call 911. Do not open windows and stay to see if it stops. Do not reset the alarm and run the furnace.

Electrical problems are a stop. Reset a tripped breaker once. If it trips again, or you see scorched wire, leave the breaker off. Do not open the blower compartment.

No heat: what you can rule out

None of these open the burner cover.

• Thermostat. Heat, not Cool or Off. Fan on AUTO, not ON. Setpoint a few degrees above the room. Fresh batteries if the screen is dim. A schedule can hold the call for a few minutes, so wait that long once.
• Filter and door. If you cannot see light through the filter, replace it with the size on the frame. Latch the blower door. A loose door keeps many furnaces from firing. Do not run the furnace with no filter.
• Switch and breaker. The furnace switch looks like a light switch on the cabinet or near the attic stairs. Reset a tripped breaker once.
• Gas valve at the furnace. The handle should be parallel to the pipe. A handle across the pipe is closed. If the stove and the water heater are also out, call the gas utility. Do not take the valve apart.
• Vent pipes you can see from the ground. White PVC intake and exhaust should be clear of leaves, a nest, or a cover. Do not climb to inspect a metal flue.

Write down a blink code if you can read it from the floor. Restart once. If you get silence, burners that light and die, or cold air that stays cold, the next step is a technician, not another reset.

A furnace that starts and stops every few minutes is a different article's pattern, but the Garland noise at startup is its own call. A boom or a squeal is a furnace making a loud noise when it starts in Garland. A smell that is more than a little dust is when a burning furnace smell is worth worrying about in Garland.

When to call

Call for furnace repair if the checks above are done and the house still will not heat. Call when you notice any of these. Do not run the furnace "to see if it clears."

• Burners light and shut off within seconds.
• A rollout switch has tripped, or you see soot, scorch marks, or a yellow flickering flame instead of steady blue.
• The same error code returns after one restart.
• Water from an attic furnace is reaching a ceiling.
• The breaker trips a second time.
• The inducer screams, grinds, or never starts.
• Anyone felt sick in the house and better outside, even if the alarm has gone quiet.

Gas smell and a sounding carbon monoxide alarm are not on that list because you should already be outside.

The part-by-part symptom list used on Arlington furnaces (igniter, flame sensor, limit, inducer, blower) is furnace repair in Arlington. The sequence is the same in Garland. The visit is the same.

What the technician checks

A no-heat call follows the sequence instead of replacing parts until something changes.

The thermostat has to be asking for heat, on the right wires. The door switch and the breaker have to be feeding the furnace. The inducer has to run and the pressure switch has to prove the vent is drafting. Only then should the igniter glow and the gas valve open. The flame sensor has to prove flame within seconds or the valve closes again. The limit and the rollout have to be closed. The blower has to move enough air that the heat exchanger stays in its temperature-rise range. On a high-efficiency furnace, a clogged condensate trap or a failed pump can open a float and stop the burners while the blower still runs.

You should hear which step failed, and the price, before parts go in. A sensor, an igniter, a capacitor, or a drain on a sound heat exchanger is often a repair. A cracked heat exchanger, a flue with holes, or a limit that keeps opening after the air problem is fixed is a replacement comparison. Ask for a free replacement estimate when that is the case. The repair quote is separate. HVAC service in Garland is the local page.

Safety, after the house is empty

If you left for gas or for a carbon monoxide alarm, do not go back in to troubleshoot. The utility or the fire department checks the air. That is not a furnace repair. The heat exchanger, the flue, and the combustion still need a technician before anyone runs the furnace again. A cleared house is not a repaired furnace.

Do not bypass a rollout switch, tape a door switch closed, or jumper a pressure switch to force heat. Those switches are the reason a failed furnace is often just cold, instead of worse.

Getting the heat back on

Boost Air And Plumbing repairs gas furnaces in Garland, Arlington, Grand Prairie, Dallas, Fort Worth, and nearby communities. We do not service boilers. See our furnace repair service and HVAC service in Garland. Call (817) 612-9107 or book online. Hours are Monday through Saturday, 8am to 7pm, with after-hours and Sunday emergency appointments available.

This guide is also available in Spanish: reparación de calefacción en Garland.

Frequently asked questions

When should I call for furnace repair in Garland? Call if the thermostat is set to Heat, the filter is clean, the breaker has been reset once, and the house still will not heat. Also call if the burners light and die, a rollout switch has tripped, you see soot or a yellow flame, the same error code returns, or the breaker trips again. Gas smell and a carbon monoxide alarm are not a repair call from inside the house.

What does the technician check on a no-heat call? The sequence, in order. Thermostat call, power and the door switch, inducer and pressure switch, igniter, gas valve, flame sensor, limit and rollout, blower, and temperature rise. Condensate safeties are checked on a high-efficiency furnace. You hear which step failed, and the price, before parts are replaced.

What should I do if I smell gas or the carbon monoxide alarm sounds? If you smell gas, do not flip switches or use a phone inside. Leave the home and call your gas utility or 911 from outside. If a carbon monoxide alarm sounds, get everyone out and call 911. Do not reset the alarm and keep the furnace running. The fire department checks the air. The heat exchanger and the flue still need a technician before the furnace runs again.

Is a furnace that will not start dangerous by itself? A furnace that simply will not light is usually the safety controls doing their job. It becomes a leave-the-house problem if you smell gas, see soot or a yellow flame, or a carbon monoxide alarm sounds. Do not keep resetting a rollout switch to get heat overnight.

Can a loud bang or a burning smell wait until morning? No. A bang at startup can be delayed ignition. Shut the furnace off. A burning smell that is more than a little dust on the first cycle of the season, or that gets stronger, is a reason to shut it off and call. The Garland noise guide and the burning-smell guide cover those two calls.