The short answer
Most Carrier gas furnaces in Northern Virginia don’t have a single reset button. You reset them by cutting the power: thermostat to OFF, the furnace switch off for 30 seconds, then back on and the thermostat back to HEAT. The button-looking things you find inside are a door switch and, on the burner box, manual-reset rollout switches, and a tripped rollout switch is a reason to call, not to press. Before any reset, count the code on the light: on older boards, cutting the power erases it.
Before you reset: count the code
Look through the small window in the lower door. Short flashes are the first digit and long flashes are the second. A steady light is normal, and rapid flashing means the line voltage polarity is reversed. Write the code down. Older Carrier boards with a red light lose it the moment the power goes off. Newer boards keep the last 7 faults. Our list of Carrier furnace codes tells you what it means, and some codes mean you shouldn’t reset at all.
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How to reset a Carrier furnace
- Set the thermostat from HEAT to OFF.
- Turn off the furnace’s power switch. It looks like a light switch on or near the furnace. If there isn’t one, use the furnace’s breaker.
- Wait 30 seconds.
- Turn the power back on and set the thermostat back to HEAT, a few degrees over the room temperature.
- Give it a few minutes. The inducer starts first, then the igniter glows, then the burners light, then the blower comes on.
Do this once. If the same code comes back, the reset didn’t fix anything, it just cleared the message.
Swipe to see all columns →
Swipe to see all columns →
| What you find | What it is | Press it? |
|---|---|---|
| A plunger button that clicks when the lower door goes on | The door switch. Carrier wires it so the blower door completes the 115-volt circuit; no door, no power | No: just put the door on tight |
| A small round disk with a button, on the burner box | A manual-reset flame rollout switch | No: call |
| A small automotive-style fuse on the control board | The 3-amp fuse for the 24-volt wiring | Only a 3-amp fuse ever goes there |
Why a rollout switch is a call
A rollout switch trips when flame comes out of the burner area where it shouldn’t. Carrier’s manual says not to bypass it and to correct the combustion air problem before resetting it. The causes behind a rollout trip, like a blocked heat exchanger or a venting problem, are the kind that put exhaust in the house. Pressing the button gets the heat back for a while and leaves the cause in place.
Lockouts reset themselves
Some codes are lockouts. Code 13 means a limit switch stayed open more than 3 minutes, and code 14 means ignition failed too many times. In both, Carrier’s board waits 3 hours and then tries again on its own. If the furnace keeps landing in a lockout, a power reset only buys time. Our posts on code 33 and 13 and code 34 and 14 cover what’s behind them.
What not to do
Never jump or bypass a safety switch to get heat back. Each one is there to stop the furnace from burning gas when something is wrong, and the wrong thing is often exhaust, which carries carbon monoxide. Don’t tape the door switch down to run the furnace with the door off. Don’t reset over and over: each restart on a furnace with a real problem puts more wear on the igniter and the inducer. If you smell gas, don’t flip any switches: leave the house and call your gas company or 911 from outside.
When to stop and call
- The same code comes back after one reset.
- A rollout switch has tripped.
- The code is 21, 22 or 45, which Carrier treats as gas valve or control problems: see codes 21 and 22 and code 45.
- You smell gas or your CO alarm sounds.
What it costs to have us look
A repair visit starts with a flat $99 diagnostic, and you get the price of the fix before we touch anything. Our Carrier repair page lists what the common repairs cost. Our heating check is $67 per system, through December 31: furnace, heat pump or boiler.
Related: Carrier furnace troubleshooting, the Carrier pressure switch, the Carrier flame sensor, resetting a Bryant, furnace won’t turn on and our error code and warning light guide.
Every code meaning here comes from Carrier’s own documents: 58SC0A installation instructions, 58TP0B manual and 59MN7C manual.
Call or book
Call (703) 997-9757 and tell us the code you counted, or book online from goswiftpro.com/cookiesoffer and a box of warm cookies comes with the visit. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
Most Carrier gas furnaces don’t have one. You reset them by turning the power off for 30 seconds and back on. The buttons inside are the door switch and the rollout switches.
How do I reset my Carrier furnace after a power outage?
Set the thermostat to OFF, turn the furnace switch off for 30 seconds, turn it back on, and set the thermostat back to HEAT. Give it a few minutes to go through its start-up.
Should I press the rollout switch reset?
No. A tripped rollout switch means flame showed up outside the burner area. Carrier says to fix the cause first, and that’s a job for a technician.
Why does my Carrier furnace keep needing to be reset?
Because the cause is still there. Count the code on the light and look it up; a clogged filter, a plugged drain or a dirty flame sensor are the usual ones.
How much does it cost to have a Carrier furnace checked?
The visit starts with a flat $99 diagnostic, and you get the price of the repair before any work starts.
