Durham Region Air Conditioning Repair, Service and Installation
If you're looking for help fixing your Heil furnace, look no further! Our comprehensive Heil furnace repair guide will explain common issues, provide troubleshooting tips, and show you how to read your model's error codes..
CODE: Heartbeat.
RESULT: Control has 24 VAC power.
RESULT: Control has 24 VAC power.
CODE: 2 Flashes.
RESULT: Pressure switch did not open, check for obstructed pressure tubing.
RESULT: Pressure switch did not open, check for obstructed pressure tubing.
CODE: 3 Flashes.
RESULT: Pressure switch did not close, or re-opened- Check for: excessive wind, proper vent size, defective inducer motor, low inducer voltage, defective pressure switch, inadequate combustion air supply, disconnected or obstructed pressure tubing, low inlet gas pressure, restricted vent, condensate clogged.
RESULT: Pressure switch did not close, or re-opened- Check for: excessive wind, proper vent size, defective inducer motor, low inducer voltage, defective pressure switch, inadequate combustion air supply, disconnected or obstructed pressure tubing, low inlet gas pressure, restricted vent, condensate clogged.
CODE: 4 Flashes.
RESULT: Limit circuit fault-a limit or flame rollout is open. Check for: restricted vent, proper vent sizing, loose blower wheel, excessive wind, dirty filter, defective blower motor, defective switch or connections, inadequate combustion air supply.
RESULT: Limit circuit fault-a limit or flame rollout is open. Check for: restricted vent, proper vent sizing, loose blower wheel, excessive wind, dirty filter, defective blower motor, defective switch or connections, inadequate combustion air supply.
CODE: 5 Flashes.
RESULT: Abnormal flame proving signal-Flame is proved while gas valve is de-energized. Check for: leaky gas valve, stuck open gas valve.
RESULT: Abnormal flame proving signal-Flame is proved while gas valve is de-energized. Check for: leaky gas valve, stuck open gas valve.
CODE: 6 Flashes.
RESULT: Failure to ignite or flame sense lost while running. Check for: Flame sensor must not be grounded, low inlet gas pressure, oxide buildup on flame sensor, Manual valve shut off, proper flame sense microamps, gas valve defective or gas valve turned off, defective hot surface igniter, control ground continuity, Inadequate flame carryover or rough ignition, green/yellow wire MUST be connected to furnace sheet metal.
RESULT: Failure to ignite or flame sense lost while running. Check for: Flame sensor must not be grounded, low inlet gas pressure, oxide buildup on flame sensor, Manual valve shut off, proper flame sense microamps, gas valve defective or gas valve turned off, defective hot surface igniter, control ground continuity, Inadequate flame carryover or rough ignition, green/yellow wire MUST be connected to furnace sheet metal.
CODE: 7 Flashes.
RESULT: Limit circuit lockout- Lockout occurs if the limit or flame rollout is open longer than 3 minutes. Control will auto reset after 3 hours. Refer to #4.
RESULT: Limit circuit lockout- Lockout occurs if the limit or flame rollout is open longer than 3 minutes. Control will auto reset after 3 hours. Refer to #4.
CODE: 8 Flashes.
RESULT: Gas heating lockout-Control will NOT auto reset. Check for: mis-wired gas valve, defective control valve.
RESULT: Gas heating lockout-Control will NOT auto reset. Check for: mis-wired gas valve, defective control valve.
CODE: 10 Flashes.
RESULT: Polarity-Line voltage, polarity reversed. If twinned, refer to twinning kit instructions.
RESULT: Polarity-Line voltage, polarity reversed. If twinned, refer to twinning kit instructions.
CODE: 1 + 2 Flashes.
RESULT: Blower on after power up- Blower runs for 90 seconds, if unit is powered up during a call for heat (R-W closed) or (R-W) opens during blower on delay.
RESULT: Blower on after power up- Blower runs for 90 seconds, if unit is powered up during a call for heat (R-W closed) or (R-W) opens during blower on delay.
CODE: 6 + 1 Flashes.
RESULT: Ignition lockout- Control will auto-reset after 3 hours. Refer to #6.
RESULT: Ignition lockout- Control will auto-reset after 3 hours. Refer to #6.
CODE: LED Off.
RESULT: Secondary voltage fuse is open- Check for: door switch not closed, 115VAC at L1 and neutral, 24VAC RED and COM BLUE, 24V Fuse 3A, short circuit in secondary voltage (24VAC wiring).
RESULT: Secondary voltage fuse is open- Check for: door switch not closed, 115VAC at L1 and neutral, 24VAC RED and COM BLUE, 24V Fuse 3A, short circuit in secondary voltage (24VAC wiring).
CODE: LED On.
RESULT: Control circuitry lockout- Auto-reset after one hour.
RESULT: Control circuitry lockout- Auto-reset after one hour.
CODE: LED SOLID.
RESULT: Gas valve relay stuck open- Flame sense circuit failure, software check error, reset power to clear lockout, replace control if status code repeats.
RESULT: Gas valve relay stuck open- Flame sense circuit failure, software check error, reset power to clear lockout, replace control if status code repeats.
See What Our Customers Are Saying:
Apr 28, 2022
I left a live chat message on their website that my air conditioning was not working. Within 1hr a representative called me to discuss my options.
The next day he came to the house to review my needs and give me a price for a new system. Price quoted was less than I expected and the installation was completed the following day. I found their salesman and the installers very knowledgeable and easy to deal with. All my questions were answered. Everything was properly explained in regards to what unit was needed and why, along with instruction where needed for use.
The installers made sure everything was working properly before they left.
Apr 28, 2022
This is to thank Twintech Heating and Cooling for their exceptional and timely service. Mitch, their technician was very courteous and generous with his time right from his first meeting with us. He not only took the time to check everything but also educated us on why we needed what he recommended. Greg and Mitch graciously accommodated us on our requested day and time for job to be done. They were both very courteous and responsive to our needs and special requests especially in a tight spot. The job was finished neatly and on time. Thank you Twintech for your great service !
Apr 28, 2022
They came the day and time they had planned for us and were very fast and efficient! The AC works amazing and it is amazing during the heat of the summer we have already got! Thanks for everything you did for us!
Apr 28, 2022
Would recommend this company to friends and family in a heartbeat. Very professional , on time and left no mess when the job was done.
Apr 28, 2022
Great customer service. Responsive and professional. I would highly recommend Twintech, I used them previously for repair service and a new air conditioner- very satisfied.
Apr 5, 2022
Our air conditioner failed. Made a call and within 15 min a technician was at our door.
The issue was fixed and many suggestions were provided.
Thanks to Mitch. Great service !
Apr 5, 2022
Our furnace was rattling, as soon as we put our air conditioner on this past week. We had researched looking for a company that was Registered with Better Business Bureau, and this company TwinTech, had A+ Rating. Scott, was immediately helpful via text/phone and sent his technician as soon as he was able...Mitchell/technician provided great professional service. Thank you TwinTech.
Sean and Debbie
Apr 5, 2022
I contacted various companies when looking to install a new furnace and I found Twintech to be transparent with their communication and approach. They had options to suit my various requirements and the price vs quality was very good. The after installation communication was also very good and they answered all queries I had.
Apr 5, 2022
My furnace broke down last month. The team was quick to respond, courteous, professional and mindful of COVID-19 concerns. I highly recommend them if you are considering replacing or servicing your HVAC equipment.
Apr 5, 2022
I was very happy with the installation and price. I would definitely recommend. Thank you 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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