Cracked Heat Exchanger: Symptoms, How It's Confirmed and What to Ask For
Signs of a cracked furnace heat exchanger, how a technician confirms one, what to ask for if your furnace is red-tagged, and when to repair or replace it.
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When a Bayport furnace needs fixing, the visit carries a $79 trip charge, dropped if you go ahead with the repair, and the price is flat-rate and written before any wrench turns. We're available 7am–9pm daily. In Inspiration, a furnace that quits during a snowstorm sometimes just has drifted snow over its PVC vents.
Bayport's furnaces come in two generations. Close to Lake St. Croix and the downtown streets, the furnace often sits in an old basement and vents into a masonry chimney that has served several appliances. Repairs there start with draft and flue checks, since crumbling mortar or an unlined flue can choke the draft or spill exhaust, and a pressure switch lockout is often the first sign.
Inspiration's furnaces are mostly high-efficiency units from the last fifteen years. Their weak points are condensate traps and drains, pressure switch hoses, igniters and flame sensors, plus snow at the vents: homes facing open prairie take the wind, and a drifted-over intake shuts the furnace down until it's cleared. Some of those furnaces may still carry a manufacturer's parts warranty if they were registered, so we look up the model and serial number before quoting parts.
Updated September 26, 2026
Every furnace repair call in Bayport starts with a $79 trip charge, waived when you approve the repair, and a written price before any work. Same prices in Bayport as in every town we serve. National averages (HomeGuide, 2026), not our prices: a PSC blower motor $500–$1,400, a variable-speed (ECM) blower motor $800–$2,300, an igniter $100–$250. More in the furnace repair cost guide.

More detail on our furnace repair page.
Symptom guides: Blowing cold air · Won't ignite · Short cycling · Blinking light codes · Pressure switch trips · Strange noises · Leaking water · Burning smell · Red tag · Carbon monoxide
Look at the two PVC pipes where the furnace vents out the side of the house. If snow has drifted over the intake or exhaust, the furnace's pressure switch keeps it from running. Clear the pipes by hand, then turn the furnace off and back on at its switch. If it still won't run, or the pipes keep drifting shut, call us; the manufacturer may offer a taller termination kit that raises them.
Almost always. A furnace that's ten to fifteen years old usually needs parts like an igniter, flame sensor, inducer or control board, and those repairs cost a fraction of a replacement. If it was registered with the manufacturer, the parts may still be under warranty, which leaves mostly labor. The exception is a cracked heat exchanger out of warranty; then we price both options in writing and let you decide.
Signs of a cracked furnace heat exchanger, how a technician confirms one, what to ask for if your furnace is red-tagged, and when to repair or replace it.
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