Durham Region Air Conditioning Repair, Service and Installation
The flashing LEDs on your furnace will correspond to a specific fault code that is shown here on their diagnostic chart.
International Comfort Products Corporation (ICP) is a company that designs, manufactures and markets central air conditioning (HVAC) systems and gas and oil furnaces for use in homes and commercial buildings. It is a unit of Carrier Global Corporation and is headquartered in Lewisburg, Tennessee, United States.
CODE: LED Off
RESULT: 24 VAC or 115 VAC is off, fuse is open.
FIX: Check whether the door switch isn't closed or for a short circuit.
RESULT: 24 VAC or 115 VAC is off, fuse is open.
FIX: Check whether the door switch isn't closed or for a short circuit.
CODE: LED On
RESULT: Soft lockout, furnace control error, 1 hour delay. If code repeats immediately following power reset, then replace control.
FIX: Will auto-reset after 1 hour.
RESULT: Soft lockout, furnace control error, 1 hour delay. If code repeats immediately following power reset, then replace control.
FIX: Will auto-reset after 1 hour.
CODE: Heartbeat
RESULT: Normal operation.
FIX: N/A.
RESULT: Normal operation.
FIX: N/A.
CODE: 2 Flashes
RESULT: Pressure switch closed when should be open.
FIX: Check for an obstruction in the pressure tubing.
RESULT: Pressure switch closed when should be open.
FIX: Check for an obstruction in the pressure tubing.
CODE: 3 Flashes
RESULT: Pressure switch open when should be closed on single stage models. Low pressure switch open when should be closed on 2 stage.
FIX: Check for: excessive wind; proper vent size; defective inducer motor; defective pressure switch; inadequate combustion air supply; disconnected or obstructed pressure tubing; or restricted vent.
RESULT: Pressure switch open when should be closed on single stage models. Low pressure switch open when should be closed on 2 stage.
FIX: Check for: excessive wind; proper vent size; defective inducer motor; defective pressure switch; inadequate combustion air supply; disconnected or obstructed pressure tubing; or restricted vent.
CODE: 4 Flashes
RESULT: Limit switch or rollout open.
FIX: Check for: restricted vent; proper vent sizing; loose blower wheel; excessive wind; dirty air filter; or defective blower.
RESULT: Limit switch or rollout open.
FIX: Check for: restricted vent; proper vent sizing; loose blower wheel; excessive wind; dirty air filter; or defective blower.
CODE: 5 Flashes
RESULT: Flame sensed out of sequence.
FIX: Check for a leaky gas valve or a gas valve that is stuck open.
RESULT: Flame sensed out of sequence.
FIX: Check for a leaky gas valve or a gas valve that is stuck open.
CODE: 6 Flashes
RESULT: Failure to ignite or flame sense lost while running.
FIX: Check for: an ungrounded flame sensor; defective hot surface ignitor; low inlet gas pressure; oxide buildup; manual valve shut off; control ground continuity; inadequate flame carryover; or rough ignition.
RESULT: Failure to ignite or flame sense lost while running.
FIX: Check for: an ungrounded flame sensor; defective hot surface ignitor; low inlet gas pressure; oxide buildup; manual valve shut off; control ground continuity; inadequate flame carryover; or rough ignition.
CODE: 6 + 1 Flashes
RESULT: Soft lockout - Max of 4 trials for ignition reached (3 hour delay).
FIX: Control will auto-reset after 3 hours.
RESULT: Soft lockout - Max of 4 trials for ignition reached (3 hour delay).
FIX: Control will auto-reset after 3 hours.
CODE: 7 Flashes
RESULT: Soft lockout - Limit of roll-out switch open longer than 2 minutes (1 hr delay)(rollout switch requires manual reset).
FIX: A lockout will occur if the limit or flame rollout is open for longer than 3 minutes. Control will auto-reset after 3 hours.
RESULT: Soft lockout - Limit of roll-out switch open longer than 2 minutes (1 hr delay)(rollout switch requires manual reset).
FIX: A lockout will occur if the limit or flame rollout is open for longer than 3 minutes. Control will auto-reset after 3 hours.
CODE: 8 Flashes
RESULT: Permanent lockout - Gas valve relay contact stuck closed or mis-wired gas valve (power reset only).
FIX: Check for a miswired gas valve or a defective control valve.
RESULT: Permanent lockout - Gas valve relay contact stuck closed or mis-wired gas valve (power reset only).
FIX: Check for a miswired gas valve or a defective control valve.
CODE: 10 Flashes
RESULT: Line voltage polarity reversed. If twinned, refer to kit instructions.
FIX: Review instructions to correct polarity.
RESULT: Line voltage polarity reversed. If twinned, refer to kit instructions.
FIX: Review instructions to correct polarity.
See What Our Customers Are Saying:
Aug 16, 2022
Very pleased with the installation of our new furnace and A/C unit. From quotation stage to the completion of the job Twintech was very professional.
Thank you for a job well done.
Aug 15, 2022
My old water heater quit on me. I called TwinTech. In less than 4 days, I had my new water heater installed and the old one taken away. The whole process was quick, easy, pleasant, and well done. This is the third time I've dealt with TwinTech and I've been satisfied each time.
Aug 14, 2022
I had them replace my furnace last year. When it came time for the air conditioner this year, I did not hesitate to call Twintech again. I will also have them perform regular maintenance on them.
Aug 13, 2022
We required a new HVAC replacement after running the old
system for 18 years.
Dave understood our requirements and gave us a quote that
covered all the necessary items.
Installation was fast and very tidy. Everything works as
it should. Our thanks to Greg, Mitch and others for their
excellent work. Recommend this family owned business to
anyone else, considering HVAC or other work.
Aug 12, 2022
I needed a new furnace and A/C to replace my 21 yr. old units, and went to the internet to view potential companies in May, I received 3 quotes,
and chose Twintech based on their salesman Dave who was very detailed and covered off everything on what Twintech was all about,
an extremely dedicated company with so many years of experience, and after reading the on line reviews I was sold on Twintech, who did not disappoint as the installation team were top notch with Greg leading,
I would highly recommend this company without any doubts, in my books they are first class all the way. Our new Amana furnace and A/C are working perfectly !
Aug 11, 2022
Flawless transaction. They did exactly what they promised, showed-up on time, cleaned-up, and were highly professional. Highly recommended.
Aug 10, 2022
Salesperson and 2 man installation team were all professional and
knew their stuff. All three were friendly and helpful, answering all
my questions. The quality of their work demonstrated their experience
and expertise in their field.
Aug 9, 2022
A dear late cousin of mine recommended this company and I have been happy with the service.
Aug 8, 2022
We are very pleased with the work done by Twintech. They were very professional from start to finish. Dave came to our home and gave us a very competitive quote for new high efficiency furnace and air conditioner. The installers were very courteous and professional. We would highly recommend them.
Aug 7, 2022
Great experience getting an old furnace replaced.
Sales Guy (Dave) was great - honest, responsive, and friendly.
The work itself was done quickly and we are very happy with the outcome, thank you! We recommend TwinTech!
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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