Quick answer: a furnace pressure switch error means the inducer fan could not prove that exhaust is venting, so the furnace will not open the gas valve. The switch itself is rarely the problem. The usual causes are blocked PVC vent pipes, a clogged condensate trap, a cracked or water-filled hose, or a weak inducer motor. It shows up as Lennox 223, Carrier 31 or 32, Goodman 3 flashes and Trane 3 blinks.
Safety first: if you smell gas, do not reset or relight anything. Leave the home and call your gas utility (Nicor Gas 1-888-642-6748, or North Shore Gas 1-866-556-6005) or 911 from outside.
Pressure Switch Codes by Brand
| Brand | Code |
|---|---|
| Lennox | 223 / E223 |
| Carrier, Bryant, Payne | 31, 32, 43 (switch did not close); 23 (did not open) |
| Goodman, Amana, Daikin | 3 flashes (will not close); 2 flashes (stuck closed) |
| Trane, American Standard | 3 blinks |
What a Pressure Switch Does
Before the burners light, the inducer motor starts and pulls air through the heat exchanger and out the vent. The draft pulls a diaphragm in the pressure switch closed, telling the control board it is safe to open the gas valve. If the draft is weak or blocked, the switch stays open and the furnace stops.
Most Common Causes in Chicago-Area Homes
- Snow and ice on the vent pipes after a storm or drifting wind.
- Clogged or frozen condensate drain on 90%+ furnaces, especially lines that run through cold garages or crawlspaces.
- Cracked or water-filled pressure switch hose.
- Weak inducer motor, often noisy before it fails.
- Vent pipe that sags and holds water.
- A failed switch, less often than people think.
What You Can Safely Check
- Clear snow and ice from the intake and exhaust pipes by hand.
- Check that the condensate pump is plugged in and not full.
- Reset power once.
Never jumper or bypass a pressure switch. It is there to keep exhaust gases, including carbon monoxide, out of the home.
What Pressure Switch Repairs Cost
| Repair | Flat-rate price |
|---|---|
| Condensate trap cleaning or replacement | $290 |
| Condensate drain line flush and clear | $290 |
| Condensate pump replacement | $435 |
| Pressure switch hose replacement | $250 |
| Pressure switch replacement | $355 |
| Flue or PVC vent pipe repair | $435 |
| Inducer motor replacement | $570 to $1,410 |
Prices are flat-rate with parts and labor, as of November 2026. The $75 diagnostic is waived when you approve the repair, and Comfort Club members save 10 to 15% on repairs. Exact pricing depends on your furnace model and whether the part is in stock on our trucks.
Seeing a pressure switch code in the Northwest Suburbs?
Pure Comfort Heating and Cooling services every major furnace brand from our shop in Streamwood, IL. Diagnostics are $75, or $99 on evenings, weekends and holidays, and the fee is waived when you approve the repair. You approve a flat-rate price before any work starts, and phones are answered 24/7.
Other Error Code Guides
- Furnace blinking light codes by brand
- Lennox furnace error codes
- Carrier, Bryant and Payne furnace codes
- Goodman, Amana and Daikin flash codes
- Trane and American Standard blink codes
Frequently Asked Questions
Can I replace a furnace pressure switch myself?
We do not recommend it. In most cases the switch is fine and is correctly reporting a venting, drain or inducer problem. Replacing it will not fix the cause.
How much does it cost to fix a pressure switch error?
With us, most pressure switch problems are fixed for $250 to $435 flat-rate. An inducer motor costs $570 to $1,410 depending on the furnace.
Why does my furnace pressure switch error only happen when it is very cold?
Condensate can freeze in drain lines, ice can form at the vent terminations, and longer run times expose weak inducers.
We diagnose and repair furnaces from our shop in Streamwood across Streamwood, Bartlett, Hoffman Estates, Schaumburg, Elgin, Hanover Park, Roselle, Arlington Heights and the rest of the Northwest and West Suburbs. See our furnace repair page for flat-rate prices.