Durham Region Air Conditioning Repair, Service and Installation
carrier furnace codes
The flashing LEDs on your furnace will correspond to a specific fault code that is shown here on their diagnostic chart.
Each of the following status codes is a two digit number with the first digit determined by number of flashes of the YELLOW L.E.D. and the second digit determined by number of flashes of the GREEN L.E.D.
If status code recall is needed, do not remove power or blower door. Briefly remove and then reconnect one main limit wire to display stored status code.
To initiate the component test sequence, shut OFF the room thermostat or disconnect the "R" thermostat lead. Briefly short the TEST terminal to the "COM24V" terminal. Status LED will flash code and then turn ON the inducer motor. The inducer motor will run for the entire component test. The hot surface ignitor, blower motor-heat speed and blower motor-cool speed will be turned ON for 10-15 seconds each. Gas Valve and humidifier will not be turned on.
CODE: CONTINUOUS OFF
RESULT: Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and SEC-2
RESULT: Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and SEC-2
CODE: CONTINUOUS ON
RESULT: Control has 24VAC power
RESULT: Control has 24VAC power
CODE: RAPID FLASHING
RESULT: Line voltage (115VAC) polarity reversed.
FIX: If twinned, refer to twinning kit instructions.
RESULT: Line voltage (115VAC) polarity reversed.
FIX: If twinned, refer to twinning kit instructions.
CODE: 1-1
RESULT: NO PREVIOUS CODE
FIX: Stored status codes are erased when power (115VAC or 24VAC) to control is interrupted or 48 hours after each fault is cleared.
RESULT: NO PREVIOUS CODE
FIX: Stored status codes are erased when power (115VAC or 24VAC) to control is interrupted or 48 hours after each fault is cleared.
CODE: 1-2
RESULT: BLOWER ON AFTER POWER UP (115VAC or 24VAC)
FIX: Blower runs for 90 seconds, if unit is powered up during a call for heat (R-W closed)
RESULT: BLOWER ON AFTER POWER UP (115VAC or 24VAC)
FIX: Blower runs for 90 seconds, if unit is powered up during a call for heat (R-W closed)
CODE: 1-3
RESULT: LIMIT OR FLAME ROLL-OUT SWITCH LOCKOUT
FIX: Control will auto reset after 3 hours. Reset switch or replace fuse link.
RESULT: LIMIT OR FLAME ROLL-OUT SWITCH LOCKOUT
FIX: Control will auto reset after 3 hours. Reset switch or replace fuse link.
CODE: 1-4
RESULT: IGNITION LOCKOUT- Control will auto-reset after three hours.
RESULT: IGNITION LOCKOUT- Control will auto-reset after three hours.
CODE: 2-1
RESULT: GAS HEATINGING LOCKOUT
FIX: Control will NOT auto reset. Check for: *Mis-wired gas valve *Defective control (Valve relay)
RESULT: GAS HEATINGING LOCKOUT
FIX: Control will NOT auto reset. Check for: *Mis-wired gas valve *Defective control (Valve relay)
CODE: 2-2
RESULT: ABNORMAL FLAME-PROVING SIGNAL
FIX: Flame is proved while gas valve is de-energized. Inducer will run until fault is cleared. Check for: *Leaky gas valve *Stuck open gas valve
RESULT: ABNORMAL FLAME-PROVING SIGNAL
FIX: Flame is proved while gas valve is de-energized. Inducer will run until fault is cleared. Check for: *Leaky gas valve *Stuck open gas valve
CODE: 2-3
RESULT: PRESSURE SWITCH DID NOT OPEN
FIX: Check for: * Obstructed pressure switch *Pressure switch stuck.
RESULT: PRESSURE SWITCH DID NOT OPEN
FIX: Check for: * Obstructed pressure switch *Pressure switch stuck.
CODE: 2-4
RESULT: SECONDARY VOLTAGE FUSE IS OPEN
FIX: Check for: *Short circuit in secondary voltage (24VAC) wiring.
RESULT: SECONDARY VOLTAGE FUSE IS OPEN
FIX: Check for: *Short circuit in secondary voltage (24VAC) wiring.
CODE: 3-1
RESULT: PRESSURE, DRAFT SAFEGUARD, AUX-LIMIT SWITCH (when used*) OR BLOCKED VENT SWITCH (when used) DID NOT CLOSE OR REOPENED (DOWNFLOW ONLY)
FIX: If open longer than five minutes, inducer shuts off for 15 minutes before retry. Check for: - Proper vent sizing - Defective inducer motor - Low inducer voltage (115VAC) - Defective blower motor or capacitor - Restricted vent - Excessive wind - Defective pressure switch - Inadequate combustion air supply - Disconnected or obstructed pressure tubing If it opens after trial for ignition period, blower will come on for 90 second recycle delay,
RESULT: PRESSURE, DRAFT SAFEGUARD, AUX-LIMIT SWITCH (when used*) OR BLOCKED VENT SWITCH (when used) DID NOT CLOSE OR REOPENED (DOWNFLOW ONLY)
FIX: If open longer than five minutes, inducer shuts off for 15 minutes before retry. Check for: - Proper vent sizing - Defective inducer motor - Low inducer voltage (115VAC) - Defective blower motor or capacitor - Restricted vent - Excessive wind - Defective pressure switch - Inadequate combustion air supply - Disconnected or obstructed pressure tubing If it opens after trial for ignition period, blower will come on for 90 second recycle delay,
CODE: 3-3
RESULT: LIMIT OR FLAME ROLL-OUT SWITCH IS OPEN
FIX: If open longer than 3 minutes, code changes to lockout #13. Flame roll-out switch requires manual reset. Check for: - Defective blower motor or capacitor - Dirty filter or restricted duct system - Loose blower wheel - Defective switch or connections - Inadequate combustion air supply (Flame roll-out switch or fuse link open) - Open Flame Roll-out Switch or fuse link. Manual reset or replace.
RESULT: LIMIT OR FLAME ROLL-OUT SWITCH IS OPEN
FIX: If open longer than 3 minutes, code changes to lockout #13. Flame roll-out switch requires manual reset. Check for: - Defective blower motor or capacitor - Dirty filter or restricted duct system - Loose blower wheel - Defective switch or connections - Inadequate combustion air supply (Flame roll-out switch or fuse link open) - Open Flame Roll-out Switch or fuse link. Manual reset or replace.
CODE: 3-4
RESULT: IGNITION PROVING FAILURE
FIX: Control will try three more times before lockout #14 occurs. If flame signal lost during blower on-delay period, blower will come on for 90 second recycle delay. Check for: - Control ground continuity - Flame sensor must not be grounded - Oxide buildup on flame sensor (clean with fine steel wool) - Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal). - Gas valve defective or gas valve turned off - Manual valve shut-off - Defective Hot Surface Ignitor - Low inlet gas pressure - Inadequate flame carryover or rough ignition - Green wire MUST be connected to furnace sheet metal.
RESULT: IGNITION PROVING FAILURE
FIX: Control will try three more times before lockout #14 occurs. If flame signal lost during blower on-delay period, blower will come on for 90 second recycle delay. Check for: - Control ground continuity - Flame sensor must not be grounded - Oxide buildup on flame sensor (clean with fine steel wool) - Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal). - Gas valve defective or gas valve turned off - Manual valve shut-off - Defective Hot Surface Ignitor - Low inlet gas pressure - Inadequate flame carryover or rough ignition - Green wire MUST be connected to furnace sheet metal.
See What Our Customers Are Saying:
Aug 8, 2025
We are very happy to recommend this company to everyone. Our furnace broke down on Sunday morning. We phoned them and before noon Grant the owner showed up. He worked on the furnace for about a hour not wanting to give up to fix the problem. The furnace was 17 years old. I was the one talking about replacing it. End result was the next day it was all done. On the Sunday Bob came over with heaters to warm up the house. We decided to replace the water heater at the same time. Thanks Grant for the excellent work. Thumbs up.
Aug 8, 2025
Right on time. Explained how to work the HRV in a different way so the house would not be so dry. Changed my whole house water filter for me as well. Friendly, helpful, caring service!
Feb 18, 2025
Very pleased with the professional service that TwinTech Heating and Cooling provided in replacing my furnace. I got several quotes from different service providers. Their price was excellent and they explained the features very well. We are very glad we went with TwinTech and highly recommend their services.
Feb 18, 2025
We were new homeowners in need of a second opinion. TwinTech Heating & Cooling were Amazing and professional. Very knowledgeable and great service all around. Recommend to anyone looking for honest and reliable services. Treated with respect and care. Thank you Greg, Mitch and Bob!
Feb 18, 2025
TwinTech is an excellent and honest company! I called them for a second opinion after being told by another company that I needed to replace my furnace. Turns out this was not the case at all! I did not need a new furnace. TwinTech did not push to make an unnecessary sale and saved me from a huge expense. Bob and Mitch were extremely professional and above all honest! I definitely recommend TwinTech!
Feb 18, 2025
Amazing experience with TwinTech Heating & Cooling! Their team was professional, knowledgeable, and efficient from start to finish. They installed my new furnace quickly and left everything spotless. The technicians took the time to explain everything and made sure I was comfortable with the system before they left. Great customer service and fair pricing. I highly recommend them for anyone needing HVAC services!
Feb 18, 2025
Great experience all around. Bob was sharp and easy to talk to, and Greg handled the installation perfectly. Would hire them again in a heartbeat.
Aug 17, 2024
I returned from vacation to find my AC unit on the Fritz. After calling way too many places I connected with TwinTech. Ive used the company in the past for my furnace so I was happy when I recognized Greg at my front door. Hes great and the service is always top notch. Id highly recommend using twintech for honest, superior service in the Durham region. Thanks!
Aug 13, 2024
I called Twin Tech when my air conditioning stopped working. Greg came over to diagnose the issue - the same day. He was able to diagnose the issue and resolve it quite quickly. Although it was a quick fix, Greg was very thorough in explaining the issue and provided great advice. Not to mention, I felt very comfortable having Greg in my home - which I consider very important when hiring a service provider. Twin Tech will be my go-to from now on. Thank you!!
Aug 12, 2024
Just hired TwinTech Heating & Cooling to do an A/C Unit removal & reinstall to allow for landscaping access on the side of my house, and they were wonderful!
Bob, Greg & Mitch make a great team! Quick appointment times, super knowledgeable, expert troubleshooting capabilities & very customer service oriented.
I would highly recommend them for all of your HVAC needs! Great job guys!!
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carrier furnace error codes
See What Our Customers Are Saying:
Aug 8, 2025
We are very happy to recommend this company to everyone. Our furnace broke down on Sunday morning. We phoned them and before noon Grant the owner showed up. He worked on the furnace for about a hour not wanting to give up to fix the problem. The furnace was 17 years old. I was the one talking about replacing it. End result was the next day it was all done. On the Sunday Bob came over with heaters to warm up the house. We decided to replace the water heater at the same time. Thanks Grant for the excellent work. Thumbs up.
Aug 8, 2025
Right on time. Explained how to work the HRV in a different way so the house would not be so dry. Changed my whole house water filter for me as well. Friendly, helpful, caring service!
Feb 18, 2025
Very pleased with the professional service that TwinTech Heating and Cooling provided in replacing my furnace. I got several quotes from different service providers. Their price was excellent and they explained the features very well. We are very glad we went with TwinTech and highly recommend their services.
Feb 18, 2025
We were new homeowners in need of a second opinion. TwinTech Heating & Cooling were Amazing and professional. Very knowledgeable and great service all around. Recommend to anyone looking for honest and reliable services. Treated with respect and care. Thank you Greg, Mitch and Bob!
Feb 18, 2025
TwinTech is an excellent and honest company! I called them for a second opinion after being told by another company that I needed to replace my furnace. Turns out this was not the case at all! I did not need a new furnace. TwinTech did not push to make an unnecessary sale and saved me from a huge expense. Bob and Mitch were extremely professional and above all honest! I definitely recommend TwinTech!
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