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:
Aug 26, 2022
This is the second time we have had Twintech to our house. A couple of summers ago they were in for an issue with our air conditioning. This time it was our furnace having an issue. It was shutting off randomly and not coming back on. Greg came right away and took the time to investigate thoroughly and explain what was going with the furnace. Both times I have been thoroughly impressed with their speed, customer service, and quality of work. I HIGHLY recommend Twintech.
Aug 24, 2022
Extremely happy.
So we were in no rush to replace our old units and took the time to do some research and get a number of quotes.
Twintech came in at around the middle of the pack for price but what convinced us to go with them was Bob, the representative that came to our house. Bob was by far the most professional of all the reps that we met with. He took the time to explain everything, what would work best for us and why. He really did seem very knowledgeable and enthusiastic about his stuff.
As promised on the day of install the crew showed up on time and got to work with minimal impact on us
..they were professional, clean, tidy and got the system up and running ahead of schedule...they made a couple of adjustments to the system to optimize it for our house.
The crew left the house clean and tidy.
Bob the rep showed up to check in and give us a few tips ..
It's been a week since install and all is good.
Our overall experience with Twintech has been excellent from start to finish and I wouldn't hesitate to recommend them.
Thank u.
Aug 23, 2022
It was a refreshing experience interacting with the Twintech team. From Bob, the sales consultant, who articulated in layman's terms all the options available and reasons for making any selection. This was done without the prevailing pressure tactics so commonplace today.
Before proceeding Mitch, the technician, at our request conducted a service check on our 30 yr old furnace. His report was positive indicating no urgency to replace it. Again no pressure tactics.
Three days after first meeting with Bob, the installation team of Greg and
Spencer completed the installation within the planned time frame.
A very professional, courteous and transparent team which delivered on their promise. I highly recommend Twintech.
Aug 22, 2022
Initial contact with sales resulted in an immediate response, which led to a timely installation. Both sales and installers were all very professional. I have no hesitation in recommending TWINTECH.
Aug 21, 2022
I had a great experience with TwinTech. The company offered a reasonable quote, and performed a quick and clean installation. The installer Greg was experienced, professional and courteous. He explained the services he performed and gave recommendations on maintain the new furnace.
The salesman Bob was honest
and professional and educated me on how to achieve optimal performance.
All communication from them was quick and they came the following day. I was pleased with the service and would recommend them.
Aug 20, 2022
From quote, to installation, to follow up, Twintech provided excellent service. I would highly recommended their services.
Aug 19, 2022
I had a really great experience with these guys. The salesman Bob was clearly very knowledgeable about everything to do with heating and cooling a home, spent a lot of time with us going over the details of the job, never rushed us and came back after the install to make sure we were happy. The installation crew was excellent, they covered the floors all the way from outside down to the basement furnace room, kept the place clean, got the work done on time and were very friendly. Ive got 15 years in the contracting/ construction industry and these guys are one of the most professional companys Ive dealt with. Great company!
Aug 18, 2022
Had great service and clean-up was good. Was happy with my salesman. They were very friendly and helpful. I needed a new furnace as our was over 20 years old. The furnace and air-conditioner work great and they are very quiet. I am very pleased with the service and product I received.
Aug 17, 2022
Met with Dave for the sales process and he was great about explaining and going over everything to us. The install happened very quickly and the team were super professional and friendly. We are very happy with this company and their services and we definitely recommend them to others. Thankful my sister recommended them to me!
Aug 16, 2022
Reviews for Twintech were good, and they did not disappoint. After an initial visit to discuss the suitable AC unit for replacement, an installation date was available in just a couple of days, and everything was installed without a hitch. Highly recommended
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!
Heat Pumps: Heating and Cooling in One System
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - May 8, 2025
When it comes to maintaining year-round comfort in your home, few systems offer the convenience and efficiency of a heat pump. What sets heat pumps apart from traditional HVAC systems is their dual functionality—the ability to both heat and
Read MoreWhat You Need to Know Before Buying a Heat Pump
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - November 13, 2023
Buying a heat pump is a significant decision that can impact your home's comfort and energy efficiency. Here are key factors to consider before purchasing a heat pump: Climate and Region: Heat pumps are most effective in moderate
Read MoreAmana Heat Pumps for Sale in Ajax
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - August 26, 2025
Looking for a dependable, energy-efficient way to heat and cool your home year-round At Twintech Heating & Cooling, we proudly offer top-of-the-line Amana heat pumps to homeowners across the Durham Region and Toronto. With professional instal
Read MoreTwintech - The Best Amana Heat Pump Installation in Toronto
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - September 22, 2025
When it comes to heating and cooling your home, choosing the right system is only half the job. To get the most out of your investment, you need expert installation from trusted professionals. At Twintech Heating & Cooling, we’re prou
Read More