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:
Jul 23, 2024
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!
Jul 18, 2024
Just had a new furnace installed by Twintech. I cant 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 !!!
Jul 17, 2024
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!
Jul 16, 2024
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.
Jul 15, 2024
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.
Jul 14, 2024
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.
Jul 13, 2024
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!!
Jan 4, 2023
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.
Jan 4, 2023
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!
Jan 4, 2023
Im going to start this by saying Im 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.
Im 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 youre being brushed off.
In summary, if youre looking for PROFESSIONAL, QUALITY results by an EXPERIENCED, THOUGHTFUL team
(that also happen to be FRIENDLY and ATTENTIVE ) then youve come to the right page!!
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!
How a Heat Pump Functions as Both a Heating and Cooling System
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - November 7, 2025
A heat pump is one of the most versatile and energy-efficient home comfort systems available today. Instead of relying on separate heating and cooling equipment, a heat pump delivers year-round comfort in a single, smart package. Many homeowner
Read MoreCommon Ways Your AC Might Break Down
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - May 18, 2024
Air conditioning systems are essential for maintaining comfort in hot weather, but they can encounter various issues that lead to breakdowns. Understanding the common causes of AC failures can help you take preventive measures and ensure timely repai
Read MoreKeeping Warm This Fall: Things to Remember
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - October 5, 2016
We can feel it in the air – the cold season is fast approaching. Keeping a home warm is not as easy as 1,2,3 especially if the home is older and doesn’t really have very good insulation. Here are some tips on how you can save money while you are
Read MoreInternal Furnace Issues
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - October 9, 2024
When addressing internal furnace issues, it's important to recognize common problems and their potential causes. Here’s a breakdown of some key internal furnace issues and how they can be resolved: 1. Clogged or Dirty Filters Cause
Read More