Red-Tagged Furnace Repair in Pittsburgh, PA

What a red tag means and who can put one on a furnace

A red tag is a warning and shut-off notice. In Allegheny County it is usually hung by a field technician from the gas utility, most often Peoples or Columbia Gas of Pennsylvania, after a leak call, a meter change or a reading taken during a service visit. An HVAC technician can also red-tag a furnace when a tune-up or repair turns up a hazard.

Usually the gas valve feeding the furnace is turned off, sometimes locked, and the tag states the reason. Do not remove the tag, cut a lock or turn the valve back on yourself. Beyond the safety risk, it can complicate getting service restored.

• Gas utility tag: often limited to the furnace, sometimes the whole meter if the leak is upstream of the appliance.
• HVAC technician tag: usually tied to a measured hazard such as carbon monoxide in the supply air or a failed draft test.
• Inspection or sale tag: a home inspector may flag a furnace, but the formal shut-off normally comes from the utility or a technician.

Keep the tag and any paperwork. The technician who repairs the furnace will need to see exactly what was written on it.

Common reasons: cracked heat exchanger, carbon monoxide readings, failed venting, gas leaks

Almost every red tag on a gas furnace traces back to one of four problems. The table shows what a technician checks for each and the usual result. The outcome always depends on what the inspection finds in your furnace.

Venting failures are common in older city homes, where an 80% furnace still exhausts into an unlined brick chimney. Condensation crumbles the mortar, debris piles up at the base and the flue chokes. On a high-efficiency furnace, a crushed or disconnected PVC vent does the same.

Those four cover most tags, but not all of them. Technicians and utility crews also tag furnaces for an old or damaged flexible gas connector, burners and heat exchangers rusted through by water from a leaky humidifier or a flooded basement, and missing or makeshift vent connections. Whatever the reason, it's written on the tag, and that wording is what the repair has to answer.

What to do first, and what not to do

Once the utility or technician has left and the house is safe to occupy, your job is to keep the family warm and get a qualified repair lined up. Here is the order that works.

1. Read the tag and any written notice, and take a clear photo of both.
2. Photograph the furnace data plate as well, and ask whoever inspects it next to photograph or record what they find, including camera images of the heat exchanger.
3. Make sure your carbon monoxide alarms work and are on every level.
4. Call (321) 478-0693 and describe what the tag says, the furnace age and, if you can see it, the model number on the data plate.
5. Keep the house above freezing with safe heat sources while you wait; see the steps on our emergency furnace repair page.
6. If you rent, tell your landlord or property manager the same day.

• Do not remove the tag or turn the gas valve back on.
• Do not let anyone relight the furnace before the hazard is repaired.
• Do not heat the house with the oven, a grill, a camp heater or a generator indoors.
• Do not use space heaters unless they are listed for indoor use, with three feet of clearance.
• Do not agree to a replacement on the spot if you have doubts about the diagnosis.

Getting a second opinion on a cracked heat exchanger

A cracked heat exchanger is the most expensive verdict a furnace can get, and it is fair to ask for proof. A careful technician builds the case from several tests, not one glance with a flashlight. When you ask for a second opinion, this is what the inspection should include.

• Camera inspection: a borescope fed through the burner openings or flue collar to look at the cells, seams and crimps where cracks usually start. Ask to see the images.
• Combustion analysis: CO and oxygen measured in the flue with a calibrated analyzer. A sudden change in oxygen when the blower starts suggests air is crossing into the combustion side.
• CO in the supply air: readings taken in the supply plenum or at a register near the furnace. Any rise above the room baseline is a red flag.
• Flame behavior at blower start: if the burner flames lift, wave or roll when the blower comes on, air is getting through the heat exchanger.

Rust scale or a surface mark is not proof of a breach, and neither is CO from a dirty burner. A sound second opinion separates those cases from a true crack.

Repair or replacement: what is actually fixable

Plenty of red-tagged furnaces are repairable. A gas leak at a union, a rusted-through flue connector, a blocked chimney base or a sooted burner set can usually be corrected and the furnace returned to service the same week. A confirmed heat exchanger crack is a different decision.

When a heat exchanger replacement makes sense

If the furnace is fairly young and the part is still made, replacing the heat exchanger alone can be reasonable. The furnace is largely taken apart, so labor is a big share of the bill. A manufacturer's parts warranty may cover the part, so find your paperwork first.

When replacing the furnace is the better call

On a furnace past about 15 years old, with an out-of-production part or a history of repairs, the money usually goes further on a new unit. That is common in the 1950s and 1960s houses of the inner-ring suburbs, many of which are on a third furnace. See furnace replacement for sizing and venting choices, and our furnace replacement cost guide for what drives the price. Either way, the technician gives you a firm price before any work starts.

Getting the gas back on: repair, paperwork and relight

Restoring heat after a red tag has two parts: correcting the hazard, then bringing the gas service and the appliance back on in the right order. The technician handles the first part and documents what was done.

The second part depends on who placed the tag and on your gas utility's own process. Some tags allow a qualified technician to restore the appliance after the repair; others require the utility to come back, inspect and turn the gas on. Follow the instructions printed on your tag or notice, and call the utility to confirm what they need before you schedule anything. Our guide to a gas company red tag walks through the questions to ask.

Once gas is restored, the technician relights the furnace and verifies it: leak test on new connections, combustion analysis, draft check, a CO reading in the supply air and a full cycle with every safety control tested. Keep that record with your tag.

We cover the city and the surrounding service areas, including Penn Hills, Ross Township and Bethel Park. Every HVAC technician we send is licensed where Pennsylvania requires it, and insured.

What affects the cost of fixing a red-tagged furnace

The tag sets the scope, so the price depends on what it names. You get a firm price after the technician has confirmed the hazard and before any work starts. These are the things that move the number:

• What was tagged. Tightening or replacing a leaking union or flex connector is a small job. A heat exchanger or a full furnace replacement is the large end.
• Venting work. Clearing a blocked chimney base costs far less than a new chimney liner or a rebuilt PVC vent run.
• Parts and warranty. A heat exchanger still under the manufacturer's parts warranty may be covered, leaving labor; an older furnace usually isn't.
• The second opinion itself. A thorough inspection with a camera and combustion analyzer is a diagnostic visit, and you're told the charge before dispatch.
• Timing. A tag on a cold night may mean an after-hours visit, which can carry a different rate that you hear about up front.

Who pays for the repair?

The utility or technician who placed the tag identifies the hazard; fixing it is up to the owner of the furnace. Homeowners arrange and pay for the repair directly. If you rent, tell your landlord or property manager the same day, since the furnace usually belongs to them, and keep a copy of the tag. Our furnace replacement page covers what a new furnace involves if the tag leads there.

Carbon monoxide alarms: where they belong in a Pittsburgh home

Working CO alarms are the backstop for the next time. In the typical Pittsburgh layout, with the furnace and water heater in the basement and bedrooms two floors up, one hallway alarm is not enough.

• One alarm outside each sleeping area, close enough to wake people.
• One on every level, including the basement near (but not right beside) the furnace and water heater.
• One in a room above an attached garage, common in split-levels and post-war ranches.
• Mount and test each alarm by the manufacturer's instructions, and replace units by the date printed on the back.

Alarms are a backup, not a substitute for a sound furnace. A yearly furnace tune-up and safety inspection with a combustion test catches most of the conditions that lead to a red tag before a utility crew ever sees them.