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What Do AC Error Codes Mean?

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What Do AC Error Codes Mean?

Posted On: June 2, 2024

What Do AC Error Codes Mean?

Air conditioning (AC) units can display error codes when something goes wrong. These codes are specific to the manufacturer and model of the AC unit, but here are some general explanations for common AC error codes:


General AC Error Codes

  1. E1/E2/E3/E4: These codes often indicate issues with sensors:


    • E1: Room temperature sensor error.
    • E2: Indoor coil sensor error.
    • E3: Indoor fan speed malfunction.
    • E4: Outdoor coil sensor error.
  2. F1/F2/F3: These codes are usually related to the frequency drive or the main control board.


    • F1: Indoor unit PCB (Printed Circuit Board) error.
    • F2: Outdoor unit PCB error.
    • F3: Outdoor ambient temperature sensor error.
  3. H1/H2/H3: These codes generally indicate protection errors.


    • H1: Defrosting mode.
    • H2: Overload protection of the compressor.
    • H3: High-temperature protection of the compressor.
  4. P1/P2/P3: These codes typically relate to pressure or system malfunctions.


    • P1: High pressure protection of the system.
    • P2: Low pressure protection of the system.
    • P3: Protection against lack of refrigerant or malfunction in the refrigerant system.
  5. L1/L2/L3: These codes can be related to electrical issues.


    • L1: Phase loss or imbalance.
    • L2: Overcurrent protection.
    • L3: Voltage error or under-voltage protection.

Manufacturer-Specific Error Codes

LG

  • CH 01: Indoor unit room temperature sensor error.
  • CH 02: Indoor unit pipe temperature sensor error.
  • CH 03: Communication error between indoor and outdoor units.

Daikin

  • U0: Low refrigerant.
  • U4: Transmission error.
  • E1: Circuit board malfunction.

Mitsubishi

  • P1: Abnormal rise in pressure.
  • P8: Outdoor unit air temperature sensor error.
  • E0: Inverter/compressor malfunction.

Samsung

  • E101: Communication error.
  • E121: Indoor temperature sensor error.
  • E154: Outdoor coil sensor error.

What to Do When an Error Code Appears

  1. Consult the Manual: The best source of information is the user manual or service manual for your specific AC model.
  2. Reset the Unit: Sometimes, resetting the unit by turning it off and on again can clear the error.
  3. Check for Obvious Issues: Ensure that filters are clean, vents are not blocked, and that there is no visible damage to the unit.
  4. Call a Professional: If the error persists, it's best to contact a professional technician. They can diagnose and fix the issue safely.

Understanding these codes can help you determine whether the issue is something simple that you can fix yourself or if you need to call a professional for assistance.



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by gerard harrington from Ajax on Twintech Heating and Cooling

Greg and team were amazing! All interaction via email and text 100% professional. From consult to product recommendation their service was phenomenal!

Installed a Napoleon furnace (ecm dc drive variable 2-stage) and it was a game changer for the whole house. Blended air temperature through and through the entire house and it’s saving us money by cutting down our utility bill by ALOT!

by D &. from Whitby on Twintech Heating and Cooling

We purchased a new cooling & heating system from Twintech and the team was fantastic. From sales to installation, the team were great to work with. Friendly (our dog even enjoyed having them over), professional and accommodating. I’d recommend Twintech in a heart beat to anyone. Superb customer service.

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End to end service. From quote, overseeing installation, contacting and making arrangements for energy audit. Warranty program is comprehensive. Cleaned up mess of assistant walking through my place without proper indoor foot covering when I pointed out that I was not happy about footprints on my floors.

by Bob S in Pickering on Twintech Heating and Cooling

In April we hired Twintech Heating & Cooling to replace our 20 year old water tank & 35 year old air conditioner. We got 5 estimates for the job & decided to go with Twintech for the following reasons.

- The Sales Manager, Dave, was very personable & knowledgeable as all of our questions were answered. (We had a list of questions we asked each of the contractors when we got the estimates)
- We got 5 estimates for the job. All contractors verbally told us they had the required qualifications but Dave was the only one to physically show us their license & insurance documentation.
- Twintech carried the Napoleon air conditioner & we wanted to support Canadian industry as it is assembled in Barrie On.

Safety is important at Twintech as demonstrated when we discussed with Dave, the need to change our install date because of freezing rain. Access was required by navigating a set of outside steps & Dave identified that safety took precedence.
On the installation date, Greg, Peter & Grant showed up on time & methodically accomplished the removal & installation of both units. The guys did a great job cleaning up as well.

When the job was completed we mentioned to Greg that we were pleased with the work they had done & were going to have them come out & do our furnace inspection in Sept. Greg said we can save our money as he had inspected the heat exchanger on the furnace while doing the job & there was no need to have another inspection in Sept. We were very impressed with Greg’s initiative. This is top shelf service. Thank you Greg.

As the weather was too cool to complete a functional test of the air conditioner on the installation date, Dave made a follow-up call to us to see how things were going & Greg also came out to check the operation. No problems.

We are very happy we hired professionals like Dave, Greg, Grant & Peter & have no hesitation in recommending Twintech Heating & Cooling. They will now be our "go to" guys.

by ted diplock in Toronto on Twintech Heating and Cooling

These guys are the best. From start to finish they exceeded my expectations and delivered a great product. They accommodated the nuances of my 100 year old home which was really appreciated. The install was easy to schedule and done fantastically. I’m so excited to have an efficiently heated and cooled home.

by Private User from Kitchener on Twintech Heating and Cooling

Twintech were fast and efficient contractors. It only took 48 hours between an initial home visit and complete installation. The workmen were polite and hardworking. The site was left clean with the old furnace etc. removed. They helped arrange an environmental assessment in order that I could receive the maximum rebate. They even called me within a week to determine if I was satisfied with their work and to reassure me that I could call them anytime I experienced heating difficulties or had any questions. I recommend Twintech for your heating problems.

by dlcarroll in Vaughan on Twintech Heating and Cooling

Courteous and professional service from initial consultation through to the installation. We highly recommend Twintech for outstanding service in the industry. Competitive pricing, professional and accurate advice, attention to detail, respect for their client's home and cleaning up at the completion of installation.

by TraceyG from Toronto on Twintech Heating and Cooling

Last night was the coldest day of the year so far and I woke up to my house being 54 degrees... I called Twintech at 2:45am and Greg was on site by 3:30am. The furnace required a part and he returned to his shop and came back to my home around 4:15am, furnace up and running by 4:30am. THANK YOU TWINTECH! Your service is second to none.

by Cristelle from Ajax on Twintech Heating and Cooling

After much research & getting 4 quotes, we hired Twintech team for our new furnace installation, prices were fair, they carried great product brands & more importantly installation was expertly done by one of the owners (Greg & his assistant Peter) which gave me an added piece of mind. Dave was very organized & answered all my questions in great detail, especially re: the Enbridge & Govt. rebate program.

by David from Pickering on Twintech Heating and Cooling

My old air conditioner was 20 years old and developed a Freon leak and it was more cost effective to replace rather than repair. There are a large number of heating and air conditioning companies available in my area so I contacted several for quotes. Twintech heating and cooling responded quickly to the inquiry I left on their website and their sales person Dave came by the following day. He was knowledgeable about the field and was able to show copies of the various refrigeration and gas fitting licenses along with workmens compensation, TSSA and other certifications. He also suggested a particular manufacturer and model of AC unit appropriate to my house and gave me a quote. Since the price was reasonable, service had been good and the reviews on the internet were also good, I decided to purchase an AC unit from them. Installation was quickly scheduled. They showed up on time, did a good job installing the new unit including some sheet metal work to get the new heat exchanger to fit in the furnace duct, and cleaned up afterward. In addition, they noticed that my existing AC was installed too close to the furnace exhaust (based on building code) and were able to mount the new AC the appropriate distance from the exhaust. Overall, they did an excellent job and were a pleasure to work with.

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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.

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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!

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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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