Durham Region Air Conditioning Repair, Service and Installation
The codes are flashed by a series of short and long flashes of the status light. The short flashes indicate the first digit in the status code, followed by long flashes indicating the second digit of the error code.
CODE: On solid, no flash.
RESULT: None.
FIX: Normal operation.
RESULT: None.
FIX: Normal operation.
CODE: Rapid continuous flashing.
RESULT: Standard Thermostat Control 288ANA/180ANA only.
FIX: Unit being controlled by standard thermostat inputs instead of Evolution Control. Only high stage operation is aveliable. This operating mode should be used in emergency situations only.
RESULT: Standard Thermostat Control 288ANA/180ANA only.
FIX: Unit being controlled by standard thermostat inputs instead of Evolution Control. Only high stage operation is aveliable. This operating mode should be used in emergency situations only.
CODE: 1 pause.
RESULT: None.
FIX: Normal operation.
RESULT: None.
FIX: Normal operation.
CODE: 2 pause.
RESULT: None.
FIX: Normal operation.
RESULT: None.
FIX: Normal operation.
CODE: 16.
RESULT: System Communications Failure.
FIX: Communication with User Interface lost. Check wiring to UI, indoor and outdoor units.
RESULT: System Communications Failure.
FIX: Communication with User Interface lost. Check wiring to UI, indoor and outdoor units.
CODE: 25.
RESULT: Invalid Model Plug.
FIX: Control does not detect a model plug or detects an invalid model plug. Unit will not operate without correct model plug.
RESULT: Invalid Model Plug.
FIX: Control does not detect a model plug or detects an invalid model plug. Unit will not operate without correct model plug.
CODE: 31.
RESULT: High Pressure Switch Open.
FIX: High - pressure switch trip. Check refrigerant charge, outdoor fan operating and coils for airflow restrictions.
RESULT: High Pressure Switch Open.
FIX: High - pressure switch trip. Check refrigerant charge, outdoor fan operating and coils for airflow restrictions.
CODE: 32.
RESULT: Low Pressure Switch Open.
FIX: Low - pressure switch trip. Check refrigerant charge and indoor air flow.
RESULT: Low Pressure Switch Open.
FIX: Low - pressure switch trip. Check refrigerant charge and indoor air flow.
CODE: 45.
RESULT: Control Fault.
FIX: Outdoor unit control board has failed. Control board needs to be replaced.
RESULT: Control Fault.
FIX: Outdoor unit control board has failed. Control board needs to be replaced.
CODE: 46.
RESULT: Brown Out (230v).
FIX: Line voltage < 187v for at least 4 seconds.
RESULT: Brown Out (230v).
FIX: Line voltage < 187v for at least 4 seconds.
CODE: 47.
RESULT: No 230v at Unit Measured at L1 and L2 on circuit board.
FIX: There is no 230v at the contactor when indoor unit is powered and cooling/heating demand exists.
RESULT: No 230v at Unit Measured at L1 and L2 on circuit board.
FIX: There is no 230v at the contactor when indoor unit is powered and cooling/heating demand exists.
CODE: 53.
RESULT: Outdoor Air Temp Sensor Fault.
FIX: Outdoor air sensor not reading or out of range.
RESULT: Outdoor Air Temp Sensor Fault.
FIX: Outdoor air sensor not reading or out of range.
CODE: 55.
RESULT: Outdoor Coil Sensor Fault.
FIX: Coil sensor not reading or out of range. Ohm out sensor and check wiring.
RESULT: Outdoor Coil Sensor Fault.
FIX: Coil sensor not reading or out of range. Ohm out sensor and check wiring.
CODE: 56.
RESULT: Thermistors out of range.
FIX: Improper relationship between coil sensor and outdoor air sensor. Ohm out sensor and check wiring.
RESULT: Thermistors out of range.
FIX: Improper relationship between coil sensor and outdoor air sensor. Ohm out sensor and check wiring.
CODE: 71.
RESULT: Low Stage Thermal Cut out.
FIX: Compressor operation detected then disappears while low stage demand exists. Possible causes are internal compressor overload trip or start relay and capacitor held in circuit too long.
RESULT: Low Stage Thermal Cut out.
FIX: Compressor operation detected then disappears while low stage demand exists. Possible causes are internal compressor overload trip or start relay and capacitor held in circuit too long.
CODE: 72.
RESULT: High Stage Thermal Cut out.
FIX: Compressor operation detected then disappears while low stage demand exists. Possible causes are internal compressor overload trip or start relay and capacitor held in circuit too long.
RESULT: High Stage Thermal Cut out.
FIX: Compressor operation detected then disappears while low stage demand exists. Possible causes are internal compressor overload trip or start relay and capacitor held in circuit too long.
CODE: 73.
RESULT: Contactor Shorted.
FIX: Compressor voltage sensed when no demand for compressor operation exists. Contactor may be stuck closed or there is a wiring error.
RESULT: Contactor Shorted.
FIX: Compressor voltage sensed when no demand for compressor operation exists. Contactor may be stuck closed or there is a wiring error.
CODE: 74.
RESULT: No 230v at Compressor.
FIX: Compressor voltage not sensed when compressor should be starting. Contactor may be stuck open or there is a wiring error.
RESULT: No 230v at Compressor.
FIX: Compressor voltage not sensed when compressor should be starting. Contactor may be stuck open or there is a wiring error.
CODE: 75.
RESULT: Low Stage Did Not Start.
FIX: Specified start voltage at VR terminal was not achieved in low stage. Start relay was de-energized after 1 second.
RESULT: Low Stage Did Not Start.
FIX: Specified start voltage at VR terminal was not achieved in low stage. Start relay was de-energized after 1 second.
CODE: 76.
RESULT: Low Stage Did Not Start 3 times.
FIX: For 3 consecutive low stage starts, the specified start voltage at VR terminal was not achieved and start relay was de-energized. Low stage locked out for 30 minutes.
RESULT: Low Stage Did Not Start 3 times.
FIX: For 3 consecutive low stage starts, the specified start voltage at VR terminal was not achieved and start relay was de-energized. Low stage locked out for 30 minutes.
CODE: 77.
RESULT: High Stage Did Not Start.
FIX: Specified start voltage at VS terminal was not achieved in high stage. Start relay was de-energized after 1 second.
RESULT: High Stage Did Not Start.
FIX: Specified start voltage at VS terminal was not achieved in high stage. Start relay was de-energized after 1 second.
CODE: 78.
RESULT: High Stage Did Not Start 3 times.
FIX: For 3 consecutive high stage starts, the specified start voltage at VS terminal was not achieved and start relay was de-energized. High stage locked out for 30 minutes.
RESULT: High Stage Did Not Start 3 times.
FIX: For 3 consecutive high stage starts, the specified start voltage at VS terminal was not achieved and start relay was de-energized. High stage locked out for 30 minutes.
CODE: 81.
RESULT: Low Stage Thermal Lockout.
FIX: Thermal cutout occurs in three consecutive low/high stage cycles. Low stage locked out 4 hours or until 24v power recycled.
RESULT: Low Stage Thermal Lockout.
FIX: Thermal cutout occurs in three consecutive low/high stage cycles. Low stage locked out 4 hours or until 24v power recycled.
CODE: 82.
RESULT: High Stage Thermal Lockout.
FIX: Thermal Lockout occurs in three consecutive high/low stage cycles. High stage locked out for 4 hours or until 24V power recycled.
RESULT: High Stage Thermal Lockout.
FIX: Thermal Lockout occurs in three consecutive high/low stage cycles. High stage locked out for 4 hours or until 24V power recycled.
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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