How to Reset a Carrier Furnace and Clear LED Fault Codes

Quick Answer

To reset a Carrier furnace: set the thermostat to OFF, then flip the furnace circuit breaker off for 30 seconds and back on. Carrier furnaces are hardwired and do not have a wall outlet to unplug. Always write down the LED blink code before resetting - the code clears after power is restored. If Code 33 or 34 returns after reset, the underlying issue has not been fixed.

In my experience, a reset is more than just a restart; it is your best diagnostic tool to see exactly where the ignition sequence is failing. While many Carrier faults are temporary glitches caused by power surges, a reset allows you to watch the inducer motor and igniter in real-time. If the code returns immediately, you are likely looking at a hardware failure rather than a simple software lockout.

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How to Reset Your Carrier Furnace

Think of a Carrier reset as a clear for takeoff signal. These boards are sensitive to power fluctuations and temporary sensor glitches, so a quick power cycle often gets things moving. However, if you find yourself resetting the unit every morning just to get through a cold snap, you likely have a dirty flame sensor or a drainage issue that the board is trying to warn you about.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Control board stored a fault code and furnace is locked out40%

Thermostat reset needed after temporary fault condition clears24%

Power interruption caused control board to freeze22%

Rollout limit switch manually tripped and requires physical reset14%

Symptoms You May Notice

Furnace not responding to thermostat heat calls
LED on control board showing a repeating fault blink pattern
Furnace was working, tripped a fault code, and now will not restart
Thermostat shows heat call is active but furnace is silent

Tools Required for Diagnosis

Flashlight (to locate rollout switch in cabinet)Screwdriver (to open cabinet door if panel-screw secured)

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

Did the reset not work?

If the problem comes back after following these steps, a component has permanently failed and needs replacement. Check the specific error code your furnace is showing:

HUB Error →3 Short 3 Long Error →34 Error →

Frequently Asked Questions

Will resetting my Carrier furnace erase the fault code history?

Most modern Carrier Infinity or Performance boards keep a Last 10 Faults log, but for the average homeowner, that info is locked away in the service menu. For older standard units, flipping the breaker usually wipes the active code immediately. That is why I always nag my customers to look at the light before they touch the power. If you don't see the code, I have to spend billable time trying to make the failure happen again.

How many times can I reset my Carrier furnace before calling a technician?

I give my family the rule of two. You can reset it once because maybe a gust of wind caused a pressure switch hiccup. You can reset it a second time if you just changed a filthy air filter. But if it trips a third time, the furnace is trying to tell you that a part is failing or a safety limit is being reached. Repeatedly resetting can overheat the heat exchanger and turn a small repair into a full furnace replacement.

My Carrier furnace reset worked but the same code came back the next day. What does this mean?

This is what I call a ghost in the machine. Usually, it is a dirty flame sensor that only fails when the humidity is high, or a condensate drain that is slowly backing up. The reset clears the lockout, but as soon as the physical conditions, like water hitting a pressure switch, return, the board shuts it down again. You need to clean the sensor or clear the drain lines before you get stuck in the cold.

Does a Carrier furnace need to be reset after a power outage?

Usually, they pop right back on. However, if the power flickered several times before going out, the control board might have latched into a lockout mode to protect itself from low voltage. If your neighbors have lights but your furnace is dead silent, try the breaker reset. It is a common service call after a storm, and nine times out of ten, a hard power cycle is all it takes.

Where is the rollout limit switch reset button on a Carrier 59TP6 furnace?

On the 59TP6, look right at the burner assembly. You will see a couple of small circular switches with two wires each. The rollout switch is the one with the little button in the middle. It is usually tucked right near the top of the burner box. Use a flashlight because they can be hard to see against the dark metal, and make sure the power is off before you go poking around in there.

Related Carrier Furnace Error Codes

Code: HUBCarrier Furnace LED Flash Codes: Complete Fault Code Guide Code: 3 Short 3 LongCarrier Furnace Code 33: Pressure Switch Fault Code: 34Carrier Furnace Code 34: Ignition Proving Failure

Models Known to Experience RESET Errors

This repair applies to most Carrier furnaces with this error code. Common model numbers include:

59TP6, 59MN7, 59SP5, 59TP6A, 58PAV

Written by

Raj Patel

HVAC & Water Systems Specialist · 15 years experience

Last verified for technical accuracy on March 14, 2026