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Most Common AC Error Codes

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Most Common AC Error Codes

Posted On: July 4, 2024

Most Common AC Error Codes

Air conditioners (AC) come with built-in error codes that help diagnose issues. Here's a list of some of the most common AC error codes and their meanings:


General AC Error Codes

  1. E1: Indoor unit temperature sensor error
  2. E2: Indoor unit coil temperature sensor error
  3. E3: Outdoor unit temperature sensor error
  4. E4: Outdoor unit coil temperature sensor error
  5. E5: Communication error between indoor and outdoor units
  6. E6: Compressor temperature sensor error
  7. E7: Outdoor fan motor error
  8. E8: Indoor fan motor error
  9. E9: Water-level alarm (for units with dehumidifiers)
  10. F0: Overload protection of compressor

Troubleshooting Tips

  • Check the Manual: Always refer to the user manual for specific error codes related to your AC model.
  • Reset the Unit: Sometimes a simple reset can clear minor glitches. Turn off the unit, wait for a few minutes, and turn it back on.
  • Inspect Filters and Vents: Clogged filters and obstructed vents can cause various errors.
  • Ensure Proper Power Supply: Verify that the AC unit is receiving the correct voltage and power.
  • Call a Professional: For complex issues, it’s best to consult a certified technician.

Understanding these error codes can help you quickly diagnose and, in some cases, resolve issues with your AC unit.



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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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See What Our Customers Are Saying:

by Aaron on Twintech Heating and Cooling

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.

by Linda on Twintech Heating and Cooling

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!

by Robert Rogers on Twintech Heating and Cooling

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.

by Robert Mizuno on Twintech Heating and Cooling

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!

by Ruth on Twintech Heating and Cooling

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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