Durham Region Air Conditioning Repair, Service and Installation
McQuay was established in 1933. She specialized in the supply and service of air conditioning, ventilation and heating equipment, as well as in the production of heating equipment - heat exchangers and radiators.
McQuay Furnace error codes are seen in three colors, red, green, and amber/yellow. Each color will also flash a specific number of times to signify a specific error. Breaking down each color, and number of flashes, will help you solve the problem you are having with your York Furnace.
CODE: SLOW GREEN FLASH
RESULT: Normal operation
RESULT: Normal operation
CODE: SLOW AMBER FLASH
RESULT: Normal operation with call for heat
RESULT: Normal operation with call for heat
CODE: RAPID RED FLASH
RESULT: Twinning error, incorrect 24V phasing.
FIX: Check twinning wiring. Flame sense current is below 1.5 microamps
RESULT: Twinning error, incorrect 24V phasing.
FIX: Check twinning wiring. Flame sense current is below 1.5 microamps
CODE: RAPID AMBER FLASH
RESULT: Check and clean flame sensor. Check for proper gas flow. Verify that current is greater than 1.5 microamps at flame current test pad.
RESULT: Check and clean flame sensor. Check for proper gas flow. Verify that current is greater than 1.5 microamps at flame current test pad.
CODE: 4 AMBER FLASHES
RESULT: The control is receiving a "Y" signal from the thermostat without a "G" signal, indicating improper thermostat wiring.
RESULT: The control is receiving a "Y" signal from the thermostat without a "G" signal, indicating improper thermostat wiring.
CODE: 1 RED FLASH
RESULT: This indicates that flame was sensed when there was not a call for heat.
FIX: The control will turn on both the inducer motor and supply air blower. A gas valve that leaks or is slow closing would typically cause this fault.
RESULT: This indicates that flame was sensed when there was not a call for heat.
FIX: The control will turn on both the inducer motor and supply air blower. A gas valve that leaks or is slow closing would typically cause this fault.
CODE: 2 RED FLASHES
RESULT: This indicates that the normally open pressure switch contacts are stuck in the closed position.
FIX: The control confirms these contacts are open at the beginning of each heat cycle. This would indicate a faulty pressure switch or miswiring. This indicates the normally open pressure switch contact did not close after the inducer was energized.
RESULT: This indicates that the normally open pressure switch contacts are stuck in the closed position.
FIX: The control confirms these contacts are open at the beginning of each heat cycle. This would indicate a faulty pressure switch or miswiring. This indicates the normally open pressure switch contact did not close after the inducer was energized.
CODE: 3 RED FLASHES
RESULT: This could be caused by a number of problems: faulty inducer, blocked vent pipe broken pressure switch hose or faulty pressure switch.
RESULT: This could be caused by a number of problems: faulty inducer, blocked vent pipe broken pressure switch hose or faulty pressure switch.
CODE: 4 RED FLASHES
RESULT: This indicates that the main limit switch has opened its normally closed contacts.
FIX: The control will operate the supply air blower and inducer. This condition may be caused by: dirty filter, improperly sized duct system, incorrect blower speed setting, incorrect firing rate or faulty blower motor. Also, this fault code could be caused by a blown fuse located on the control board.
RESULT: This indicates that the main limit switch has opened its normally closed contacts.
FIX: The control will operate the supply air blower and inducer. This condition may be caused by: dirty filter, improperly sized duct system, incorrect blower speed setting, incorrect firing rate or faulty blower motor. Also, this fault code could be caused by a blown fuse located on the control board.
CODE: 5 RED FLASHES
RESULT: This fault is indicated if the normally closed contacts in the rollout switch opens.
FIX: The rollout control is manually reset. If it has opened, check for proper combustion air, proper inducer operation, and primary heat exchanger failure or burner problem. Be sure to reset the switch and cycle power (24 VAC) to the control after correcting the failure condition. Also, this fault code could be caused by a blown fuse located on the control board.
RESULT: This fault is indicated if the normally closed contacts in the rollout switch opens.
FIX: The rollout control is manually reset. If it has opened, check for proper combustion air, proper inducer operation, and primary heat exchanger failure or burner problem. Be sure to reset the switch and cycle power (24 VAC) to the control after correcting the failure condition. Also, this fault code could be caused by a blown fuse located on the control board.
CODE: 6 RED FLASHES
RESULT: This indicates that after the unit was operating, the pressure switch opened 4 times during the call for heat.
FIX: If the main blower is in a "Delay on" mode, it will complete it, and any subsequent delay off period. The furnace will lock out for one hour and then restart.
RESULT: This indicates that after the unit was operating, the pressure switch opened 4 times during the call for heat.
FIX: If the main blower is in a "Delay on" mode, it will complete it, and any subsequent delay off period. The furnace will lock out for one hour and then restart.
CODE: 7 RED FLASHES
RESULT: This fault code indicates that the flame could not be established. This no-light condition occurred 3 times (2 retries) during the call for heat before locking out.
FIX: Low gas pressure, faulty gas valve, dirty or faulty flame sensor, faulty hot surface ignitor or burner problem may cause this. The furnace will lock out for one hour and then restart.
RESULT: This fault code indicates that the flame could not be established. This no-light condition occurred 3 times (2 retries) during the call for heat before locking out.
FIX: Low gas pressure, faulty gas valve, dirty or faulty flame sensor, faulty hot surface ignitor or burner problem may cause this. The furnace will lock out for one hour and then restart.
CODE: 8 RED FLASHES
RESULT: This fault is indicated if the flame is lost 5 times (4 recycles) during the heating cycle.
FIX: This could be caused by low gas pressure, dirty or faulty flame sensor or faulty gas valve. The furnace will lock out for one hour and then restart.
RESULT: This fault is indicated if the flame is lost 5 times (4 recycles) during the heating cycle.
FIX: This could be caused by low gas pressure, dirty or faulty flame sensor or faulty gas valve. The furnace will lock out for one hour and then restart.
CODE: 9 RED FLASHES
RESULT: Indicates reversed line voltage polarity or grounding problem.
FIX: Both heating and cooling operations will be affected. check polarity at furnace and branch. Check furnace grounding. Check that flame probe is not shorted to chassis.
RESULT: Indicates reversed line voltage polarity or grounding problem.
FIX: Both heating and cooling operations will be affected. check polarity at furnace and branch. Check furnace grounding. Check that flame probe is not shorted to chassis.
CODE: 10 RED FLASHES
RESULT: Flame sensed with no call for heat.
FIX: Check gas valve and gas valve wiring This indicates that a primary or auxiliary limit switch has opened its normally-closed contacts and has remained open for more than five minutes.
RESULT: Flame sensed with no call for heat.
FIX: Check gas valve and gas valve wiring This indicates that a primary or auxiliary limit switch has opened its normally-closed contacts and has remained open for more than five minutes.
CODE: 11 RED FLASHES
RESULT: This condition is usually caused by a failed blower motor or blower wheel.
FIX: Cycle power (24 VAC) to the control to reset the hard lockout condition after correcting the failure condition.
RESULT: This condition is usually caused by a failed blower motor or blower wheel.
FIX: Cycle power (24 VAC) to the control to reset the hard lockout condition after correcting the failure condition.
CODE: 12 RED FLASHES
RESULT: This code indicates an open igniter circuit.
FIX: This could be a disconnected or loose wire or a cracked or broken igniter.
RESULT: This code indicates an open igniter circuit.
FIX: This could be a disconnected or loose wire or a cracked or broken igniter.
CODE: STEADY ON RED
RESULT: Control failure.
FIX: Replace control board.
RESULT: Control failure.
FIX: Replace control board.
CODE: 60-MINUTE AUTOMATIC RESET FROM LOCKOUT
RESULT: This control includes a "watchdog" type circuit that will reset from a lockout condition after 60 minutes. Operational faults 6, 7, 8 will be reset. This provides protection to an unoccupied structure if a temporary condition exists causing a furnace malfunction. An example would be a low incoming gas supply pressure preventing unit operation When the gas pressure is restored, at some point the "watchdog" would restart the unit and provide heat for the house.
RESULT: This control includes a "watchdog" type circuit that will reset from a lockout condition after 60 minutes. Operational faults 6, 7, 8 will be reset. This provides protection to an unoccupied structure if a temporary condition exists causing a furnace malfunction. An example would be a low incoming gas supply pressure preventing unit operation When the gas pressure is restored, at some point the "watchdog" would restart the unit and provide heat for the house.
CODE: IGNITION CONTROL FLAME SENSE LEVELS
RESULT: Normal flame sense current is approximately 3.7 microamps DC Low flame signal warning starts at 1.5 microamps. Low flame signal control lockout point is 0.1 microamps DC.
RESULT: Normal flame sense current is approximately 3.7 microamps DC Low flame signal warning starts at 1.5 microamps. Low flame signal control lockout point is 0.1 microamps DC.
See What Our Customers Are Saying:
Apr 28, 2022
We wanted to get our AC replaced as it was 22-years old and added to this our furnace was costing more and more to repair. So, we decided to get both the furnace and AC replaced.
After going through a few quotes and product reviews we decided to go with Twintech. The three-men crew arrived early in the morning, wasted no time and got to work right away. By 2:00 pm, they were all done. Ive found their work to be top notch and they were completely professional. I had all my questions answered to my satisfaction both during the progress of their work and at end.
I have pleasure in recommending Twintech to anyone who is looking to get their furnace or Ac replaced
Nathan S.
Apr 28, 2022
Our air conditioner died On a Saturday and within hours Dave came out to take a look and discuss replacement/repair options.
The new air conditioner was installed on the Wednesday. The new unit was installed quickly. The installers were friendly and cleaned up afterwards.
We noticed a slight leak around the furnace that night and they came out the next day and fixed the issue. It has been working great and is quieter than our previous unit.
Very satisfied and would highly recommend TwinTech.
Apr 28, 2022
I contacted TwinTech to replace my 20-year old A/C. Dave, their service rep, promptly replied and was at my home within 2 hours. He was friendly and knowledgeable and didn't try to upgrade or oversell their A/C units but suggested the best fit for my small 1000 feet bungalow. Although this was during a heatwave and very busy, they were able to fit me in 2 days later. The TwinTech crew installed a 1.5 ton Ducane A/C unit that is now running smoothly while maintaining a constant cooling temperature. The crew were very courteous, professional and efficient and I will definitely recommend TwinTech to family and friends. I much appreciated your great service.
Nancy M., Oshawa
Apr 28, 2022
We had a great experience. The guys who installed our a/c did a nice job. Cleaned up.
Apr 28, 2022
excellent crew, fast and efficient! Would call them again when I need a new furnace.
Apr 28, 2022
Professional, courteous and efficient, dont need to say more than that! Use them you will not regret it.
Apr 28, 2022
TwinTech was a pleasure to deal with from the estimate through installation. We replaced a 28 year old a/c unit with one recommended by TwinTech's sales representative Dave who took the time to go over the product with us and answer any questions. The warranty is for 10 years parts and labour and they will complete the registration for you. Installation was by Greg (owner) and Mitch and Spencer who were quick and efficient and left everything clean and tidy.
Apr 28, 2022
Very professional, from the sales consultation and inspection to the final installation. Met every expectations we had for the job. A local business with great client support. We highly recommend. Twintech is a blue chip! Thanks!
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 !
See What Our Customers Are Saying:
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.
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