Carrier Furnace Error Code 13 Troubleshooting

You wake up and your house feels very cold. You walk down to your basement to check the heating machine. You look through the small clear window on the metal door. You see a tiny yellow light blinking at you. It blinks one short time and then three long times. This means the machine is locked. Learning proper Carrier furnace error code 13 troubleshooting helps you understand why your heater stopped working. The machine is trying to tell you that it got dangerously hot inside. We will help you find the blocked air and reset your system today.

What The Error Means

The Safety Lockout

Your heavy metal machine has a smart computer brain. This brain watches a tiny metal thermometer called the high limit switch. If the metal walls get way too hot, the switch trips and turns the big gas fire off. If this happens three times in a row, the computer locks the whole machine for three hours. This lock keeps your house safe from a terrible fire.

Trapped Hot Air

The machine creates a massive amount of hot air. A heavy fan motor must push this heat into your rooms. If the hot air gets trapped inside the basement box, the metal gets incredibly hot very fast. You must find out what is trapping the air before you try to start the fire again. You can use our HVAC Calculators to see if your system is the right size for your specific house.

DIY Maintenance Tip

The Dirty Filter Problem

A totally black paper air filter is the number one reason for an overheating code. The heavy fan cannot pull clean cold air through a solid wall of dog hair and grey dust. The machine suffocates and overheats in just five minutes. You must pull your old filter out right now. Hold it up to a ceiling light. Throw it in the trash if you cannot see the light shining through the paper. Push a brand new white filter into the metal slot. Check the EPA Indoor Air Quality page to learn how clean filters help your family breathe safely.

Finding The Blocked Air

Closed Room Vents

You must walk into every single room in your house. Look at the metal grates on your floors and ceilings. Many people close these vents in empty bedrooms to save money. This is a very bad idea. Closed vents push the hot air backward into the basement machine. Make sure every single metal vent is wide open so the hot air can escape safely.

A Dirty Blower Wheel

Sometimes the main pushing fan gets completely covered in sticky dust. The heavy metal wheel cannot scoop the air if the curved blades are full of dirt. The fan spins but no air moves. A professional worker must take the heavy metal wheel outside and wash it with a powerful water hose. Read our Carrier Furnace Blinking Red Light Codes guide to learn about other fan motor warnings.

Average Repair Costs

System Component	Main Purpose	Expected Lifespan	Estimated Part Cost	Estimated Labor Cost
Paper Air Filter	Lets the machine breathe	One single month	$10 to $20	Free to do yourself
High Limit Switch	Watches the metal heat	Ten to fifteen years	$20 to $40	$100 to $150
Blower Motor	Pushes the hot air	Ten to fifteen years	$150 to $300	$200 to $400
Control Board	Acts as the main brain	Ten to fifteen years	$200 to $400	$300 to $500

When To Call A Pro

A Broken Limit Switch

The tiny metal switch gets weak after many years of getting hot and cold. Sometimes the switch breaks and thinks the machine is overheating even when the metal is perfectly cool. A professional heating worker will remove the old switch and put a brand new silver switch into the metal wall. They know exactly how to handle the fragile wires safely. Review the Energy.gov Home Heating Systems page for safe equipment tips.

Is your house freezing cold because your machine is locked? Are you worried about touching the electrical wires? Our expert heating team can safely reset your smart computer board today. We carry brand new silver limit switches and clean paper filters in our work trucks. We will fix your overheating problem and make your family warm again.

FAQ

What does the number 13 code mean on my machine?

It means the safety limit switch tripped three times in a row because the metal box got way too hot and the computer locked the gas valve for three hours.

Can I reset the three hour lockout myself?

You can flip the main power switch on the side of the furnace off and back on to reset the timer but the machine will just lock again if you do not fix the blocked air.

Why does my heater get so hot inside the metal box?

The heavy machine overheats very quickly because a totally dirty air filter stops the cold room air from flowing over the hot metal fire tubes.

How much does it cost to buy a brand new limit switch?

A licensed professional worker will usually charge between $120 and $190 to bring a new switch and install it safely inside the dark metal cabinet.

Will opening all my room vents help fix this error?

Yes, you must open every single floor and ceiling vent in the entire house so the heavy fan can push the trapped hot heat out of the basement.

Conclusion

A blinking yellow light is a serious warning sign. Your heavy heating machine is suffocating from a lack of cold air. You must check your paper air filter right now. Walk around your house and open every single metal floor vent. Flip the power switch off to reset the smart computer. A professional worker can safely install a new temperature switch for about $150. Read our Master Your Furnace Filter Direction Arrow Merv Ratings Guide to learn how to install your new filter perfectly. Use our HVAC Services page or call us directly to get safe heating help fast.