Cracked Heat Exchanger: Symptoms and How It's Confirmed
Signs of a cracked furnace heat exchanger, how a technician confirms it with a camera and CO readings, what to do after a red tag, and repair vs replace.
Read the guide
Furnace Repair in South St. Paul, MN
South St. Paul furnace calls are a $79 trip charge up front, waived when you say yes to the work, and you get a written flat-rate price first. Many older South St. Paul houses vent the furnace into a masonry chimney, so draft is an early check.
Furnace repair calls in South St. Paul homes
About a quarter of South St. Paul's houses predate 1940 and another quarter went up in the 1950s, so repair calls lean old. In the pre-war blocks above the bluff, some houses still heat with hot-water or steam boilers, and the calls there are weeping relief valves, waterlogged expansion tanks, tired circulator pumps and, on steam, low-water cutoffs. Forced-air houses from both eras often have a replacement furnace venting into a masonry chimney.
The vent pipe between furnace and chimney gets extra attention in South St. Paul, because it's on the city's time-of-sale checklist: holes, gaps, a pipe that doesn't run uphill or joints without three screws are marked hazardous. If we find one on a repair visit, we point it out and price the fix alongside the worn igniter, flame sensor or inducer that brought us there.
Updated October 27, 2026
What do common furnace repairs cost in South St. Paul?
National averages (HomeGuide, 2026), not our prices: a limit switch $100–$375, a control board $300–$650, an inducer motor $400–$1,100. More in the furnace repair cost guide.
Symptom guides: Won't ignite · Short cycling · Blinking light codes · Pressure switch trips · Signs your furnace needs a technician
Furnace repair in South St. Paul: questions
Our South St. Paul furnace vents into the old chimney. What draft problems show up in winter?
A cold masonry chimney on an outside wall can stall or reverse its draft, and the furnace and water heater then spill exhaust at the draft hood or lock out on a pressure switch. Fallen mortar or tile at the chimney base, a connector that doesn't run uphill, or a tight house with strong bath and kitchen fans make it worse. We run both appliances together, test draft and measure carbon monoxide, and tell you whether the fix is a connector, a liner or a replacement.
The time-of-sale report on our South St. Paul house flagged the furnace vent pipe. What does the fix involve?
Usually a new vent connector: approved pipe that runs uphill from the furnace to the chimney, three screws at every joint, sealed tightly at the chimney with an approved sealant rather than silicone or latex caulk, and the right clearance to wood (6 inches for single-wall pipe, 1 inch for double-wall B-vent). We finish by testing draft at both appliances. Some hazard corrections need a city permit.
More in South St. Paul
- Furnace replacement in South St. Paul
- AC repair in South St. Paul
- AC replacement in South St. Paul
- Heat pumps in South St. Paul
- Mini-splits in South St. Paul
- Boiler service in South St. Paul
- Tune-ups in South St. Paul
- All HVAC service in South St. Paul
Furnace repair near South St. Paul
- Newport, MN furnace repair · 2 mi
- Inver Grove Heights, MN furnace repair · 3 mi
- West St. Paul, MN furnace repair · 4 mi
- St. Paul Park, MN furnace repair · 4 mi
- Woodbury, MN furnace repair · 4 mi
- Maplewood, MN furnace repair · 5 mi
Brands we repair
Guides on furnace repair
Rheem and Ruud Furnace Error Codes: What They Mean
Rheem and Ruud furnace error codes from Rheem's own 801T manual: what 11, 22, 33, 55 and 57 mean, how to read the display, and when to call a technician.
Read the guideFurnace Pressure Switch: What It Does and Why It Trips
A furnace pressure switch proves the inducer is venting exhaust before the gas can open. Why it trips in a Minnesota winter, what you can check, and the cost.
Read the guideContact Us
Heat out? AC quit? Call or send a request.