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mcquay furnace error codes

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mcquay furnace error codes
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mcquay furnace codes

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

CODE: SLOW AMBER FLASH
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

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.

CODE: 4 AMBER FLASHES
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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

CODE: STEADY ON RED
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.

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.

mcquay furnace error codes

mcquay furnace codes


See What Our Customers Are Saying:

by Jacqueline Graham on Twintech Heating and Cooling

Twintech Heating & Cooling installed my furnace in 2022 and in fall of 2023 installed my Panasonic Heat Pump. Greg and Mitch did a great job. Helped me through the rebate process. Super happy with the Heat Pump. Only used my furnace 5 times this winter. Energy bills lower, carbon emissions lower.Thank you Twintech. I recommend highly!

by Bill Grainger on Twintech Heating and Cooling

Just had a new furnace installed by Twintech. I can’t express how great these guys are at what they do. From the sales to installation they were professional all the way. Very reasonable pricing and courteous during the installation and willing to answer any questions I had. Highly recommended !!!

by Colin Vernon on Twintech Heating and Cooling

They've cleaned my furnace a couple of times and mentioned that the hot water tank standards were going to change soon so I decided to change mine out.

There were a few challenges during the process but the installers handled the problems without missing a stride! I now have really hot water again!

by Heidi B on Twintech Heating and Cooling

Highly recommend Twintech Heating company, we got honest and detailed information on what was needed to replace and install a new gas furnace. Bob and Greg made us feel comfortable withe process through their thorough explanation and knowledge of the right furnace for our needs. The professionalism and courteous friendly attitude towards the customer is what we liked the most as they treated us like family. So happy with our decision and new furnace we will be looking into get our rental water heater replaced and installed by Twintech team. We feel better having their knowledge on our side and will only trust them with any further maintenance of furnace.

by Kirushanth Rasiah on Twintech Heating and Cooling

Customer service and knowledge is priority in this industry, and Twintech has it. I've dealt with their team for maintenance and a furnace replacement. They're accommodating and make great recommendations, and came through at a great price over the big guys in the industry. They'll be my next call when I need service or maintenance.

by Leonard Glass on Twintech Heating and Cooling

I decided that the noises and age of the existing furnace which was old and not very efficient to replace it. Gave Greg a call and Grant and Greg got to work on it. Because of supply issues with the current heating type that would be an easier install Greg convinced me to change the location of the system and it would provide me better service for heat and efficiency. I had skeptical but went ahead anyway putting trust in Greg And Grant. Greg, Grant and Mitch came through and in 2 days had completely relocated my heating and A/C system. I can honestly say Greg was right my old house has been warmer and more evenly heated as it ever was. For anyone reading this rather long winded review can take my word for it, Twin Tech can take care of your needs.

by Nicole Alain on Twintech Heating and Cooling

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!!

by Cibele Ceroni on Twintech Heating and Cooling

Great Team! Furnace broke in the weekend, Bob visited same day and Greg installed new one on Monday. Team was professional, respectful and knowledgeable. Installation went very well, Greg found solutions to challenges, like hiding new conduits in the ceiling. Looks nice and new furnace is working great. Five Stars.

by Jackie Graham on Twintech Heating and Cooling

I used Twintech to install a new furnace for my home. Bob was terrific in explaining the sizing options and why the 2 stage furnace was the best option for me. Greg did a great job installing, clean and on time. Finished work looks great but the best part is how it works. The 2 stage heating is so much more comfortable. I run the fan continuously to keep the indoor air clean. Great investment! Would highly recommendTwintech!

by Anthony Silva on Twintech Heating and Cooling

I’m going to start this by saying I’m a very particular customer. My background is in mathematics and mechanical engineering so I have an eye for detail and a respect for technical knowledge.
Greg had already done an AC inspection and replaced a water heater tank and there was no question in my mind who to deal with replacing my rickety old furnace after it got pooched.
Bob dropped in ahead of time and clearly (and knowledgeably) outlined all technical, price and operational options.
Greg showed up on time, on the agreed date and did a fantastic job. (The OLD furnace was a house of horrors and was installed in a keystone cops sort of way- careless.)
The work Greg did was HIGHLY PROFESSIONAL and FAR MORE FUNCTIONAL than what I had.
I’m also a musician with many instruments so maintaining predictable humidity/temperature is extremely important to me. Greg recognized this as did Bob. You NEVER feel like you’re being brushed off.
In summary, if you’re looking for PROFESSIONAL, QUALITY results by an EXPERIENCED, THOUGHTFUL team
(that also happen to be FRIENDLY and ATTENTIVE ) then you’ve come to the right page!!

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mcquay furnace error codes

See What Our Customers Are Saying:

by Jacqueline Graham on Twintech Heating and Cooling

Twintech Heating & Cooling installed my furnace in 2022 and in fall of 2023 installed my Panasonic Heat Pump. Greg and Mitch did a great job. Helped me through the rebate process. Super happy with the Heat Pump. Only used my furnace 5 times this winter. Energy bills lower, carbon emissions lower.Thank you Twintech. I recommend highly!

by Bill Grainger on Twintech Heating and Cooling

Just had a new furnace installed by Twintech. I can’t express how great these guys are at what they do. From the sales to installation they were professional all the way. Very reasonable pricing and courteous during the installation and willing to answer any questions I had. Highly recommended !!!

by Colin Vernon on Twintech Heating and Cooling

They've cleaned my furnace a couple of times and mentioned that the hot water tank standards were going to change soon so I decided to change mine out.

There were a few challenges during the process but the installers handled the problems without missing a stride! I now have really hot water again!

by Heidi B on Twintech Heating and Cooling

Highly recommend Twintech Heating company, we got honest and detailed information on what was needed to replace and install a new gas furnace. Bob and Greg made us feel comfortable withe process through their thorough explanation and knowledge of the right furnace for our needs. The professionalism and courteous friendly attitude towards the customer is what we liked the most as they treated us like family. So happy with our decision and new furnace we will be looking into get our rental water heater replaced and installed by Twintech team. We feel better having their knowledge on our side and will only trust them with any further maintenance of furnace.

by Kirushanth Rasiah on Twintech Heating and Cooling

Customer service and knowledge is priority in this industry, and Twintech has it. I've dealt with their team for maintenance and a furnace replacement. They're accommodating and make great recommendations, and came through at a great price over the big guys in the industry. They'll be my next call when I need service or maintenance.

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